A thoughtwise approach to CT iterative reconstruction

This very wise phi­los­o­phy for imple­ment­ing iter­a­tive dose reduc­tion in any CT pro­gram was well pre­sented at the recent MDCT meet­ing of the ISCT in San Fran­cisco in June. A key com­po­nent is to have reg­u­lar and mea­sur­able ways for radi­ol­o­gists to reg­u­larly grade or score image qual­ity as dose is ramped down slowly with increas­ing amounts of iter­a­tive recon­struc­tion. With Model Based Iter­a­tive Recon­struc­tion (MBIR), it may be pos­si­ble to drop dose up to 60% com­pared to oth­er­wise low dose adap­tive sta­tis­ti­cal iter­a­tive recon­struc­tion meth­ods (ASIR) – but not in one jump. It takes time to get accus­tomed to the slightly dif­fer­ent look of images with iter­a­tive reconstruction.

At least a month’s worth of expe­ri­ence should accrue before pass­ing judg­ment on image qual­ity. It is also impor­tant to guard against anec­do­tal cases used to ren­der judg­ments, so expe­ri­ence over time is impor­tant. But with a method­i­cal approach, a lot of progress can be achieved in over­all dose reduction.

Low-dose CT technique in diagnosing Crohn’s disease

Patients with Crohn’s dis­ease often are young and often have their dis­ease activ­ity assessed repeat­edly with CT – though MR is used more fre­quently now as well.

So – they are good can­di­dates for reduc­ing radi­a­tion dose by means of iter­a­tive reconstruction.

This paper demon­strates that con­sid­er­able reduc­tion of dose can be achieved with­out dam­ag­ing image quality.

CT radiation dose reduction by iterative reconstruction in lymphoma staging

There are some who say that iter­a­tive recon­struc­tion should be reserved only for younger patients and not used on older can­cer patients who already have seri­ous disease.

But many patients with malig­nan­cies are younger or are being treated for cure.

This arti­cle sug­gests that an iter­a­tive recon­struc­tion tech­nique (such as model-based iter­a­tive recon­struc­tion, MBIR) which can reduce patient radi­a­tion dose by 50% may have salu­bri­ous util­ity in patients with lym­phomas – who often are younger, who get mul­ti­ple CT scans, and who are being treated for cure.  

This may apply to other malig­nan­cies as well.

Educating patients about radiation dose

The ulti­mate goal is to have a fully informed and well edu­cated patient – this will result in best per­son­al­ized health­care and outcomes.

So as far as radi­a­tion dose from indi­vid­ual CT exams is con­cerned, it is good for patients to know what they received – but it is not enough. Patients also need to be edu­cated about the mean­ing and risk of their radi­a­tion dose.

Edu­cat­ing patients about extremely low risk is dif­fi­cult – as would be true about any very low risk. But, it should be cou­pled with edu­cat­ing patients about the poten­tial health and health­care ben­e­fits from their CT exam.

This is because what they really need to know is their risk/benefit ratio – from each CT exam. An edu­cated patient who under­stands their risk/benefit ratio from CT will be a truly informed health­care consumer.

Who should edu­cate patients about risk and ben­e­fit? All of us – all providers. The pri­mary care physi­cian, the sub­spe­cial­ist, the radi­ol­o­gist, the CT tech­nol­o­gist, the radi­ol­ogy nurse, PA’s and LPN’s – every­one who con­tacts the patient can help advance this edu­ca­tion and this understanding.

MDCT 2014 speak­ers weighed in on this sub­ject at the ISCT Sym­po­sium in early June.

Applying Appropriate Use Criteria to Medical Imaging Decisions

It is still true that the best way to max­i­mize value and impact on dis­ease while min­i­miz­ing cost and radi­a­tion dose is to do only appro­pri­ate exams and not do inap­pro­pri­ate exams. But how to decide what is appro­pri­ate? Many of the stan­dard cri­te­ria – such as those pub­lished by the ACR – are as evi­dence based as the cur­rent peer-reviewed lit­er­a­ture evi­dence will sup­port. But some­times there may not be sci­en­tific evi­dence avail­able for a hard clin­i­cal ques­tion – par­tic­u­larly if a ran­dom­ized trial might be very expen­sive and take a long time. Under those cir­cum­stances, expert opin­ion is often a pretty good alternative.

Expert opin­ion can be incor­po­rated into com­put­er­ized deci­sion sup­port pro­grams but also into daily prac­tice. Indeed, every radi­ol­o­gist is on their own an expert in imag­ing and its appro­pri­ate use – which is valu­able if they use this local exper­tise to guide choice of exams through being a consultant.

Your prac­tice should make radi­ol­o­gist con­sul­ta­tion easy to access … and widely known as a valu­able service.

See this arti­cle.

Significant radiation dose reduction without sacrificing image quality

At the 2014 ISCT-sponsored MDCT meet­ing in San Fran­cisco – dose reduc­tion was a key theme dur­ing all four days.

Iter­a­tive recon­struc­tion was a com­mon theme of an over­all dose reduc­tion pro­gram. While adap­tive sta­tis­ti­cal iter­a­tive recon­struc­tion (ASIR) now has been well-shown to reduce aver­age doses by up to 40% with­out impact on image qual­ity, the hot topic was model-based iter­a­tive recon­struc­tion (MBIR) in its var­i­ous forms.

Con­sen­sus is now devel­op­ing around MBIR being capa­ble of 50–70% dose reduc­tions incre­men­tal to adap­tive sta­tis­ti­cal iter­a­tions. While image appear­ance may be some­what dif­fer­ent from that of fil­tered back pro­jec­tion, it is now pretty clear that such dif­fer­ent appear­ance does not com­pro­mise diag­nos­tic power. Indeed, with expe­ri­ence, some radi­ol­o­gists have devel­oped a pref­er­ence for the image appear­ance of MBIR.

Lowering medical radiation dose with CT and other modalities in cancer patients

It is often said that radi­a­tion from diag­nos­tic imag­ing is not an impor­tant issue in can­cer patients.

But this report sug­gests oth­er­wise – as expressed by oncologists.

Many patients with can­cer are young and/or are being treated for cure. Many have long life expectan­cies despite hav­ing cancer.

And the basic prin­ci­pal of “Do no harm” plus that of ALARA still apply – as much to can­cer patients as to any other patient with a seri­ous disease.

So we should be striv­ing for max­i­mal diag­nos­tic infor­ma­tion from min­i­mal radi­a­tion dose with CT and other modal­i­ties in can­cer patients, too.

Maintaining image quality with reduced dose in coronary CT angiography

As explained in this study, here’s another trick for reduc­ing both the patient radi­a­tion dose and the patient iodine dose in car­diac CTA: lower the kVp to 100 or 80 or even lower.

Of course, you can accom­plish this same out­come by using dual energy CT and view­ing the ves­sels with lower keV or kVp while view­ing every­thing else at higher energies.

The Challenge of Tailoring Care to Individual Patients

This arti­cle goes straight to the heart of the chal­lenge of tai­lor­ing care to each indi­vid­ual patient. Such a tai­lor­ing chal­lenge bumps up against algo­rith­mic appro­pri­ate­ness analy­ses, par­tic­u­larly those which are com­put­er­ized for deci­sion sup­port. Gen­er­al­ized appro­pri­ate­ness may not ide­ally apply to indi­vid­ual patients and their unique situations.

How we bal­ance these chal­lenges is to be worked out — to fail at this chal­lenge would be to com­pro­mise care, both over­all and indi­vid­u­ally. The com­ing 5 years will be very inter­est­ing for this balance.

Striving towards ALARA

This direc­tion of com­bin­ing a higher noise index (NI) to get lower dose images and then cor­rect­ing for the resul­tant noise by using an increased per­cent of iter­a­tive recon­struc­tion (ASIR) is exactly the way to go when striv­ing towards “as low as rea­son­ably achiev­able” (ALARA) – in my opinion.

At UWMC, we have for a cou­ple of years now gone even fur­ther – we use NI in the 30–36 range and rou­tine 70 per­cent ASIR as a stan­dard for all our CT imag­ing except high res­o­lu­tion lung (which is NI 25 and ASIR 30%). Accord­ing to the ACR CT Dose Reg­istry, we are in the bot­tom 10% of their data base for CT dose….. but the images are very good.

Check out this arti­cle to learn more.

Using CT to Search for Urinary Tract Stones

CT to search for uri­nary tract stone is a very com­monly per­formed pro­ce­dure because both neg­a­tive and pos­i­tive results may have sig­nif­i­cant impact on sub­se­quent patient care. Often the patients are younger since stones can occur at any age.

This arti­cle presents very encour­ag­ing news about sig­nif­i­cantly low­er­ing the dose of a CT for uri­nary stones by using sta­tis­ti­cal iter­a­tive recon­struc­tion — yet with accept­able image qual­ity and no loss of diag­nos­tic power.

This report adds to a rapidly grow­ing body of data about both sta­tis­ti­cal iter­a­tive recon­struc­tion and model based iter­a­tive recon­struc­tion for var­i­ous types of CT exams.  This body of data almost uni­formly reports sub­stan­tial patient radi­a­tion dose reduc­tion in the 30% to 60% range with equal or even bet­ter image quality.

Lung Cancer Screening in High Risk Patients

For the ques­tion of whether lung can­cer screen­ing in high risk patients causes more good than harm, check out this arti­cle.

I’m pretty con­vinced the data shows that in a research study high risk pop­u­la­tion where the scans are read by highly skilled experts closely fol­low­ing the rules, lives are saved by CT screen­ing and the cost is rea­son­able for each QUALY.

Fur­ther, the inter­pre­ta­tion of these chest CT screen­ing exams is fairly straight­for­ward for expe­ri­enced and trained radi­ol­o­gists. That sug­gests that when CT screen­ing is extended beyond research to broader com­mu­nity prac­tice, results should also be good.

Analyzing the Cost-effectiveness of Low-dose CT

We already know that low-dose CT is a valu­able tool for reduc­ing mor­tal­ity rates, but now there’s evi­dence that it might reduce finan­cial costs as well. A new analy­sis of the 2010 National Lung Screen­ing Trial (NLST) shows that low-dose CT is a cost-effective diag­nos­tic tool for patients at high-risk of lung can­cer, accord­ing to AuntMinnie.com.

The Med­ical Imag­ing and Tech­nol­ogy Alliance (MITA) released a state­ment say­ing the orga­ni­za­tion wel­comes the analy­sis and “looks for­ward to ongo­ing col­lab­o­ra­tion with patient advo­cates and oth­ers in the imag­ing com­mu­nity to ensure access to this life­sav­ing technology.”

In my opin­ion, though, the key ques­tion in whether low-dose screen­ing for lung can­cer is cost effec­tive is: what is the cost of work­ing up the false pos­i­tives? That cost needs to be sub­tracted from the cost ben­e­fit of the lives saved. This new analy­sis sug­gests that low-dose screen­ing is indeed cost effec­tive. One thing no cost analy­sis con­sid­ers: the value of a neg­a­tive exam to a very wor­ried patient.

Fur­ther new twist: we now can do ultra-low-dose lung can­cer screen­ing using fully model-based iter­a­tive recon­struc­tion tech­niques. This tech­nique enables a 60 per­cent radi­a­tion dose reduc­tion (down to the sub-0.5 mSv range) below that of even recent low-dose CT – fur­ther sub­stan­tially decreas­ing any down­side from lung can­cer screen­ing in high-risk patients.

Best Way to Reduce CT Radiation Dose in Children? No Unnecessary Testing

A Uni­ver­sity of Wash­ing­ton study fea­tured in the August issue of JAMA Pedi­atrics claims that 4 mil­lion annual pedi­atric CT scans of the head, spine, abdomen and pelvis are pre­dicted to cause nearly 5,000 future can­cers, accord­ing to HealthImaging.com. How­ever, the study goes on to state that the risk can be mit­i­gated by CT dose reduc­tion and appro­pri­ate imag­ing ini­tia­tives which have the poten­tial to pre­vent more than half of the pro­jected radiation-related can­cers. Prac­tices like elim­i­nat­ing unnec­es­sary scans and tar­get­ing high-dose scans are called out in the study.

I believe that the best way to reduce radi­a­tion dose from CT in chil­dren is to not do stud­ies which are inap­pro­pri­ate or which have a very low chance of pro­duc­ing impact­ful diag­nos­tic infor­ma­tion. The next best way to reduce dose is to pay close atten­tion to all the tricks of tech­nique: accu­rate patient cen­ter­ing in the gantry, use of radi­a­tion shields, use of 80 or 100 kVp, min­i­miz­ing Z axis scan length, etc. Then newer tech­nol­ogy will greatly fur­ther reduce dose – auto­mated tube cur­rent mod­u­la­tion, iter­a­tive recon­struc­tion – espe­cially fully model-based iter­a­tive recon­struc­tion. Together these can reduce radi­a­tion dose by 70–80 per­cent. Scan­ning in kids above 6–8 mSv should be a thing of the past and sub-1.0 mSv scans should be common.

Update Needed for CCTA Training Guidelines

The fol­low­ing pas­sage, from an arti­cle on HealthImaging.com, caught my attention:

The hon­ey­moon has ended for coro­nary CT angiog­ra­phy (CCTA) and the seven-year itch has com­menced for some radi­ol­o­gists and car­di­ol­o­gists. They do not advo­cate replac­ing the tech­nique though. Rather, they are ask­ing if the require­ments in train­ing guide­lines need a makeover to reduce vari­abil­ity and bet­ter max­i­mize CCTA’s poten­tial to improve patients’ clin­i­cal care and out­comes.

This brings up a good point: the cre­den­tial­ing cri­te­ria for per­form­ing and inter­pret­ing car­diac CT are now too low. I found the learn­ing curve was long with a grad­ual slope. You need to be in a train­ing and super­vised envi­ron­ment with a fairly good case load for at least a year. It’s chal­leng­ing, but per­formed well and inter­preted with skill, it is a very valu­able test which can save the health­care sys­tem con­sid­er­able cost – espe­cially in low– to moderate-risk chest pain patients pre­sent­ing to an emer­gency room.

Studies Offer Hope for Future CT Protocol Comparisons

recent study fea­tured in the Jour­nal of Com­puter Assisted Tomog­ra­phy touches on the peren­nial issue for radi­ol­ogy researchers study­ing and eval­u­at­ing the effec­tive­ness of dif­fer­ent low-dose pro­to­cols. The topic brings the need for accu­rate CT dose report­ing to the fore­front, as researchers use dif­fer­ent tech­niques to com­pare dose lev­els with­out rely­ing on unnec­es­sary CT scans in the same patient.

At the Mayo Clinic, researchers have used iter­a­tive recon­struc­tion to acquire half-dose vir­tual colonoscopy exams to com­pare with full-dose exams. Pre­vi­ously, radi­o­log­i­cal researchers have relied on phan­tom stud­ies to approx­i­mate dose dif­fer­ences among dif­fer­ent pro­to­cols, or on patient divi­sion, in which patient groups (that are sim­i­lar but never match pre­cisely) undergo dif­fer­ent scan pro­to­cols to approx­i­mate dose differences.

The issue, how­ever, is that radi­a­tion dose and image qual­ity must be com­pared in every patient, not just groups, because dis­crep­an­cies in patient shape, car­diac out­put, lesion pathol­ogy, and other fac­tors are highly indi­vid­u­al­ized. The study con­tin­ues, “matched-cohort research stud­ies can’t eval­u­ate the impact of noise reduc­tion on reader per­for­mance for iden­ti­fy­ing find­ings, and even back-to-back full– and half-dose stud­ies can­not con­trol for the effect of phase enhance­ment on lesion conspicuity.”

Both of these points are valid. But, there is hope in the form of pos­i­tive sci­en­tific stud­ies on the way. Research from the Uni­ver­sity of Wash­ing­ton will soon be pub­lished in the Amer­i­can Jour­nal of Roentgenol­ogy involv­ing patients with cir­rho­sis and hyper­vas­cu­lar liver tumors. This research offers valu­able infor­ma­tion for the future of low-dose CT recon­structed with mul­ti­ple tech­niques from the same data set when com­par­ing lesion detection.

Addi­tion­ally, research involv­ing the chal­lenge of scan­ning the same patient twice with two dif­fer­ent dose lev­els is ongo­ing. The Insti­tu­tional Research Board has approved this study at a num­ber of insti­tu­tions, which ana­lyzes patients who are scanned with ASIR and then full-iterative tech­niques. Stay tuned for full data avail­able next year.

While these chal­lenges do indeed exist, these ongo­ing stud­ies offer hope for the effec­tive­ness of low-dose pro­to­cols and under­stand­ing which pro­to­cols work most effectively.

Despite Initial Challenges, ACR Dose Index Registry is a Success!

The Amer­i­can Col­lege of Radiology’s (ACR) CT Dose Index Reg­istry (DIR) pro­gram was intro­duced in May 2011. The DIR is a data reg­istry that allows insti­tu­tions across the United States to send their anonymized CT exam dose infor­ma­tion to the ACR to be saved in a data­base at ACR. Insti­tu­tions are then pro­vided with semi-annual feed­back reports com­par­ing their results by body part and exam type to aggre­gate results for adult and pedi­atric exams. Facil­i­ties can then com­pare their CT dose indices to regional and national values.

At UW, we enrolled in the DIR in May 2011 and since then have been send­ing encrypted DICOM struc­tured dose report files from all of our CT scan­ners to ACR. Doing so required col­lab­o­ra­tion between ACR, IT, PACS per­son­nel and the on-site physi­cist. Imple­men­ta­tion involved sev­eral chal­lenges, includ­ing soft­ware instal­la­tion and data trans­mis­sion con­sis­tency prob­lems. Since numer­ous insti­tu­tions are involved, the ACR required an exam map­ping process via the Radlex Play­book to unify the pro­to­col clas­si­fi­ca­tion. This map­ping process has been the most chal­leng­ing fac­tor in the imple­men­ta­tion process. These chal­lenges have been over­come and data is being suc­cess­fully trans­mit­ted to and ana­lyzed by the ACR.

The first report com­par­ing adult patient dose data (CTDI and DLP by med­ical exam­i­na­tion and by scan) between our site and oth­ers around the region and coun­try was made avail­able in Jan­u­ary 2012 and the sec­ond one in Sep­tem­ber 2012.  For each exam, the report includes box-plots and his­togram data for a vari­ety of stan­dard pro­to­cols.  The sec­ond report esti­mated the size spe­cific dose esti­mate from the scout for each patient exam.

The ACR CT Dose Index Reg­istry pro­gram has been very suc­cess­ful and is a use­ful tool for dose data min­ing and will even­tu­ally estab­lish national bench­marks for CT dose indices.

For more infor­ma­tion on the Reg­istry, please see this arti­cle here!

A Radiologist Replies to ‘Medical Radiation Soars, With Risks Often Overlooked’

A few weeks ago, the New York Times fea­tured an arti­cle, “Med­ical Radi­a­tion Soars, With Risks Often Over­looked.” The arti­cle brought up some valid points about radi­a­tion, but also requires read­ers to take a step back when pro­cess­ing some of the infor­ma­tion given.

Yes, as the arti­cle ascer­tains, radi­a­tion has its indis­putable med­ical advan­tages, in addi­tion to its poten­tial med­ical down­sides. The amount of med­ical imag­ing, includ­ing CT scans, has sig­nif­i­cantly increased over the last few decades, as more life-saving pro­ce­dures are dis­cov­ered and as tech­nol­ogy devel­ops. As a result, some patients are sub­jected to higher lev­els of radi­a­tion, which, accord­ing to this arti­cle, is “believed to account or 1.5 per­cent of can­cers” in the United States.

The piece goes on to say that “the cancer-causing effects of radi­a­tion are cumu­la­tive” and that doc­tors and hos­pi­tals fail to track the amount of radi­a­tion patients have already been exposed to when order­ing a new exam. While it is crit­i­cal to prac­tice “As Low As Rea­son­ably Achiev­able” (ALARA) for every pro­to­col and to closely scru­ti­nize every exam request for appro­pri­ate­ness, there is absolutely no evi­dence that risk from well spaced CT exams is cumu­la­tive. There­fore, can­cel­ing an oth­er­wise appro­pri­ate exam because of cumu­la­tive dose may not be in the patient’s best inter­ests. For all CT exams a risk/benefit eval­u­a­tion should be made by a well informed radi­ol­o­gist. For the exis­tence of mul­ti­ple prior exams alone to change the risk/ ben­e­fit ratio would be extremely rare.

Addi­tion­ally, the claim that “no one” keeps track of how much radi­a­tion patients have been exposed to is inac­cu­rate. A num­ber of insti­tu­tions, includ­ing UW, are a part of the Amer­i­can Col­lege of Radiology’s Dose Index Reg­istry, a pro­gram striv­ing to accu­rately track CT radi­a­tion dose in order to estab­lish bench­marks, mon­i­tor patient radi­a­tion dose expo­sure, and com­pare pat­terns. More recently, a pedi­atric dose reg­istry was intro­duced to per­form sim­i­lar func­tions, but for a younger demographic.

Both doc­tors and patients should be as informed as pos­si­ble when it comes to radi­a­tion. Under­stand­ing the risk/ ben­e­fit ratio is an impor­tant part of this—and no appro­pri­ate med­ical imag­ing exam should be can­celled if it will ben­e­fit the patient, espe­cially if its radi­a­tion level is ALARA.

Radiology on the Horizon: Can a Pill Prevent Cancer?

In July’s Radi­ol­ogy, a new study was fea­tured that sug­gests that a new pill can pre­vent DNA dam­age that might lead to can­cer. Researchers ana­lyzed DNA dou­ble strand breaks (a pre­cur­sor lesion to can­cer) before and after X-raying human blood that had been mixed with the pill, a com­pound of antiox­i­dants and glutathione-elevating agents.

At this point, the most com­mon way to pre­vent radi­a­tion dam­age, which can dam­age the DNA, is low­er­ing the radi­a­tion dose level and expo­sure timeshield­ing, and stay­ing away from radioac­tive sources. How­ever, fur­ther research may prove that this pill could be an addi­tional way to pre­vent radi­a­tion dam­age. Accord­ing to this study, there was a 58 per­cent reduc­tion in dou­ble strand breaks from sub­jects who ingested the com­pound one hour prior to imaging.

The idea is in its first stages so it remains exper­i­men­tal and eso­teric, but my esteemed col­league, James Brink, MD, from Yale has done an analy­sis of the research. He says:

“The study was very excit­ing from a method­olog­i­cal stand­point. I was impressed with the meth­ods by which the authors were able to assess the for­ma­tion of dou­ble strand breaks in response to low doses of ion­iz­ing radi­a­tion using the flu­o­res­cent tag­ging technique.

I’m respect­ful of the chal­lenges, but with­out a clear-cut iden­ti­fi­able clin­i­cal ben­e­fit, we only have a lab­o­ra­tory ben­e­fit. While many lab stud­ies on the bio­chem­istry of antiox­i­dants have been encour­ag­ing, some clin­i­cal stud­ies have not shown antiox­i­dants to be ben­e­fi­cial to sub­jects. That’s why we’d want to be cau­tious about jump­ing the gun.”

Though addi­tional research must be done to assess the wide­spread ben­e­fits of the use of this com­pound prior to imag­ing, its poten­tial ben­e­fits could be great for radi­a­tion dam­age reduction.

Chronic Kidney Failure: Dual-Energy CTA is Best Bet!

Don’t Skip the CTA” that’s the word going out to patients with advanced renal fail­ure based on find­ings of researchers in Bal­ti­more.  In a study pre­sented at June’s Inter­na­tional Soci­ety for Com­puted Tomog­ra­phy (ISCT), Dr. Barry Daly demon­strated how CTA using mod­er­ate doses of IV con­trast neg­a­tively affects only a small per­cent­age of patients and pro­vides valu­able infor­ma­tion that out­weighs the chance of adverse effects.

How­ever, because lower dose is bet­ter for patients, espe­cially that small por­tion at risk with nor­mal doses, Daly and his team also did a study of low-kVp, low-contrast-dose CTA in chronic renal fail­ure patients. This tech­nique is pos­si­ble due to the advances in CT tech­nol­ogy that have allowed radi­ol­o­gists the abil­ity to get more out of smaller amounts of iodine.

While the low kVp tech­niques enabled much lower doses of iod­i­nated con­trast and resulted in images that looked great, the dual-energy CT tech­nique may have accom­plished this effect even better!

With dual-energy, you get the best of both worlds. You get the ben­e­fit of lower kVp effect (kEv in GE units), plus the abil­ity to look at images which are equiv­a­lent to 100 or 120 kVp from the same CT raw data. Essen­tially, you still achieve sub­stan­tial iodine dose reduc­tion, but also get very dense HU enhance­ments in ves­sels and organs.

The bot­tom line is this: CTA isn’t some­thing that patients with advanced renal fail­ure should think about skip­ping. There is a too big a risk for going into surgery with­out one.  The key is find­ing the safest tech­nique to reduce the dosage level of iod­i­nated con­trast while get­ting the best images.  Dual-energy CT may be the best solu­tion out there.

Study Offers Promising Benefits for Iterative Reconstruction

At UW, we are out­spo­ken for our sup­port of adap­tive sta­tis­ti­cal iter­a­tive recon­struc­tion (ASIR).  As a big pro­po­nent of the method, I find this write-up from Radi­ol­ogy to be a land­mark arti­cle, and the research it high­lights, very impres­sive work.

A team of researchers recently con­firmed that iter­a­tive recon­struc­tion allows sig­nif­i­cant CT radi­a­tion dose reduc­tions for patients under­go­ing urolithi­a­sis imag­ing, with­out unin­tended decreased image qual­ity or diag­nos­tic confidence.

Urolithi­a­sis is a com­mon con­di­tion, with high like­li­hood (esti­mated at 75 per­cent) of recur­rence amongst indi­vid­u­als diag­nosed. There­fore, imag­ing scans are a reg­u­lar­ity for those patients with the dis­ease. It is impor­tant to treat these patients with the low­est radi­a­tion dose pos­si­ble, as to alle­vi­ate fear of poten­tially exces­sive radi­a­tion.

For the 25 patients involved in the study, image qual­ity was sig­nif­i­cantly boosted by adding iter­a­tive recon­struc­tion, while dose was reduced by about 85 per­cent, thanks to the ultra-low dose. While pre­vi­ous stud­ies report sub­stan­tial degra­da­tions in imag­ing qual­ity, 80 per­cent of the images acquired in this study had sub­op­ti­mal image quality.

This study is just fur­ther evi­dence of the promis­ing ben­e­fit of ASIR. I firmly believe that every imag­ing site with access to the pro­to­col should use it reg­u­larly as to lower dose by 80 per­cent in fre­quently per­formed exams.

To learn more about iter­a­tive recon­struc­tion, please click here!

Risk Model Emerges for CT Lung Cancer Screening!

A new risk model for lung can­cer was recently high­lighted in the August 21 issue of Annals of Inter­nal Med­i­cine. Accord­ing to the report, the Liv­er­pool Lung Project (LLP) risk model was devel­oped to deter­mine, based on spe­cific and sophis­ti­cated assess­ments, which indi­vid­u­als would ben­e­fit most from CT lung screen­ing.

The LLP risk model has a strong abil­ity to pre­dict lung can­cer, and, accord­ing to prin­ci­pal inves­ti­ga­tors, does so bet­ter than smok­ing dura­tion or fam­ily his­tory. In fact, this data has been con­firmed by researchers from the Uni­ver­sity of Liv­er­pool, as well as sev­eral U.K. cen­ters, the U.S. National Can­cer Insti­tute, and the Har­vard School of Pub­lic Health.

Unlike some other major dis­eases, like breast can­cer and heart dis­ease, lung can­cer, thus far, has lacked ade­quate iden­ti­fi­ca­tion tools to deter­mine which patients should be tar­geted to max­i­mize screen­ing ben­e­fits, and min­i­mize its poten­tial harms. Iden­ti­fi­ca­tion of those with the high­est risk for lung can­cer, a dis­ease which now kills upwards of 1 mil­lion annu­ally, will make the best use of the benefit-harm ratio.

Though other risk mod­els have been cre­ated, none have been able to suc­cess­fully apply to all of the world’s pop­u­la­tion. The LLP could over­come these chal­lenges, though, as it accounts for impor­tant risk fac­tors that oth­ers skip, includ­ing his­tory of pneu­mo­nia, non-lung can­cer, and asbestos expo­sure, among fam­ily his­tory and smok­ing history.

The model cer­tainly appears a good way to improve patient selec­tion. As always, the key inscreen­ing exams is to do no harm. Even for those patients deemed appro­pri­ate for screen­ing by the LLP, the best approach is with ultra-low dose CT— such as done with model based iter­a­tive recon­struc­tion.

To learn more about the LLP, please click here!

New Dose-Reduction Technique Optimizes Dose in Evolutionary Ways

At the recent Inter­na­tional Soci­ety for Com­puted Tomog­ra­phy (ISCT) annual meet­ing, held in San Fran­cisco, Dr. Eliot Siegel, from the Uni­ver­sity of Mary­land, dis­cussed an evolv­ing tech­nique for CT dose-reduction. This appli­ca­tion does not focus on sim­u­lated image noise as a mea­sure of image qual­ity, but instead, works to more accu­rately depict that noise in low-dose CT scans. In other words, this tech­nique aims to opti­mize dose based on what the radi­ol­o­gist needs to see.

Accord­ing to the pre­sen­ta­tion, the future of low– dose opti­miza­tion will rely on a com­bi­na­tion of the visual per­cep­tion sys­tem and sophis­ti­cated math­e­mat­i­cal mod­els designed to min­i­mize the dose for every imag­ing exam with­out impair­ing the qual­ity of the image to the radi­ol­o­gist. In fact, the cur­rent meth­ods for low-dose opti­miza­tion are already on the way out as aware­ness for radi­a­tion dose con­tin­ues to evolve.

Dr. Siegel’s analy­sis of noise in the new world of iter­a­tive recon­struc­tion is very sophis­ti­cated and thought­ful. Con­cepts of pink and white noise plus just-noticeable dif­fer­ences really are cut­ting edge. These ideas will clearly advance our under­stand­ing of how to get a world of fully auto­mated dose minimization.

Dr. Siegel and his team of researches, as usual, are think­ing pro­foundly and in very inno­v­a­tive ways. These con­cepts cer­tainly raise great hope for a much more sys­tem­atic future com­bined with much more sophis­ti­cated math to make patient doses even lower than we had pre­vi­ously dreamed! It will be an excit­ing next three years for dose reduc­tion tech­niques and technology!

When It Comes to Cardiac CT, Specialized Credentialing is Essential

The topic of car­diac CT cre­den­tial­ing came up at the recent Inter­na­tional Soci­ety for Com­puted Tomog­ra­phy meet­ing and raises inter­est­ing points on the spe­cial­ized train­ing. Some won­der with the com­pre­hen­sive res­i­dency and fel­low­ship train­ing that’s required to earn the title of “radi­ol­o­gist”, just how nec­es­sary this spe­cial cre­den­tial­ing for car­diac CT is. Dr. U. Joseph Schoepf of the Med­ical Uni­ver­sity of South Car­olina points out that it is essen­tial and ideal for car­diac imaging.

Schoepf notes, “The truth is that car­diac CT is the new kid on the block for many prac­ti­tion­ers who fin­ished their train­ing more than a decade ago.” He went on to say that any­one who wants to read car­diac CT needs spe­cial train­ing, but “there aren’t enough insti­tu­tions out there that have enough vol­ume in car­diac CT to really appro­pri­ately train res­i­dents and fellows.”

Dr. Schoepf is 100 per­cent cor­rect. Car­diac CT requires rel­a­tively exten­sive sub­spe­cialty train­ing plus a fair amount of expe­ri­ence for pro­fi­ciency. Even a Board Cer­ti­fied Radi­ol­o­gist can’t pick it up overnight or at a week­end course.

Sub­spe­cialty cer­ti­fi­ca­tion and re-certification after an appro­pri­ate time are very good ini­tia­tives. A Cer­ti­fi­ca­tion of Added Qual­i­fi­ca­tion (CAQ) in car­diac CT is just as mean­ing­ful as one in Pedi­atric Radi­ol­ogy or Inter­ven­tional Radi­ol­ogy. It pro­vides some assur­ance about a radiologist’s level of knowl­edge and prac­tice excellence.

To read more about the impor­tance of expe­ri­ence when it comes to CT, please click here.

Get Started! Steps for Implementing Dose Reduction Programs.

At a recent Soci­ety for Pedi­atric Radi­ol­ogy (SPR) meet­ing in San Fran­cisco, one pre­sen­ta­tion addressed low-dose CT’s “bright future, but trou­bled present.” Texas Children’s Hospital’s Dr. R. Paul Guiller­man touched on the many uncer­tain­ties and chal­lenges involved in low-dose radi­a­tion opti­miza­tion, cit­ing that these goals are so com­plex that they may nearly be impossible.

But, let’s take another look at this. Yes—dose reduc­tion is com­plex and full of poten­tial traps lead­ing to poor tech­nique or image qual­ity. How­ever, that is not a rea­son to avoid imple­ment­ing a dose reduc­tion (tech­nique opti­miza­tion) pro­gram at your institution!

So, how do you lead your insti­tu­tion down a road towards dose reduc­tion? First, start with Google. Read what you can find on the topic. Then, go to meet­ings, talks, and pre­sen­ta­tions given by experts with con­sid­er­able expe­ri­ence in the endeavor. Finally, start at your own institution.

I would sug­gest try­ing one vari­able at a time. Imple­ment a weight based (or cross-sectional area based) kVp selec­tion pro­gram. Then, embark on under­stand­ing how to use weight (or BMI) based selec­tion of Noise Index for auto­mated tube cur­rent mod­u­la­tion. Don’t for­get to check out the easy stuff — like patient cen­ter­ing, use of bis­muth shields, and lim­it­ing Z axis. Real­ize that even your con­trast injec­tion pro­to­cols — vol­ume, rate, blend­ing — might ben­e­fit from a weight based approach. Decide how to imple­ment iter­a­tive recon­struc­tion, var­ied by body region.

With these steps you are set to embark on a con­tin­ual jour­ney. Get started… today!

First Look: Pediatric Dose Registry

Pedi­atric radi­a­tion dosage con­tin­ues to be a hot topic in the news. Just recently, a new team of researchers stepped out with a goal of reduc­ing over­all radi­a­tion expo­sure level for pedi­atric patients. The team, called the Qual­ity Improve­ment Reg­istry in CT Scans in Chil­dren (QuIRCC), is made up of researchers from six children’s hos­pi­tals and is cur­rently in the process of research­ing and devel­op­ing the first pedi­atric CT dose index registry.

The QuIRCC comes after a May 9 man­date from the U.S .Food and Drug Admin­is­tra­tion (FDA) requir­ing man­u­fac­tur­ers to design scan­ners with young patients in mind, intended to reduce over­all radi­a­tion expo­sure lev­els in pedi­atric patients.  How­ever, the QuIRCC project is about more than just man­u­fac­tur­ing. In fact, the project is designed to help “child-size” scan­ning pro­to­cols by offer­ing accu­rate met­rics to mea­sure radi­a­tion expo­sure in children.

The devel­op­ment of such a reg­istry for chil­dren, alone, is espe­cially impor­tant. But the other impor­tant fea­ture here in this project is estab­lish­ing the tar­get ranges of dose per exam type that are con­sid­ered accept­able. This should lower or damp down the large range of vari­ance in dose for sim­i­lar exam types between nearby med­ical centers.

Here at UW we know the impor­tance of dose reg­istry pro­grams, as we got involved in the Amer­i­can Col­lege of Radi­ol­ogy Dose Index Reg­istry pilot project right away.  This new dose index reg­istry will make great strides for ensur­ing safe radi­a­tion prac­tices for patients of all ages.

CT Scans and Children–Consider the Risk/ Benefit Ratio

A new pedi­atric imag­ing study has been mak­ing head­lines, but it’s impor­tant for patients to keep in mind both the risks and ben­e­fits of CT scans when eval­u­at­ing the research. The study, pub­lished this week in Lancet, a British med­ical jour­nal, claims that CT scans expose chil­dren to can­cer caus­ing radi­a­tion.

Accord­ing to the researchers, for every 10,000 CT scans per­formed on chil­dren under the age of 10, one addi­tional child will get a brain tumor and another child will get leukemia within 10 years of the ini­tial scan. The research claims that these can­cers would not have oth­er­wise been expected regard­less of med­ical imag­ing exams.

How­ever, this arti­cle doc­u­ments an extremely small risk. In fact, this fig­ure is less than what we have been assum­ing his­tor­i­cally prior to any evi­dence. But, the arti­cle also cau­tions that any deci­sion on whether or not to scan should involve a risk/ ben­e­fit ratio con­sid­er­a­tion. The study does not change our assess­ment of risk in that ratio. Thus, the poten­tial ben­e­fit from CT remains the crit­i­cal deter­mi­nant on whether to per­form a scan.

As always, the ACR appro­pri­ate­ness guide­lines help with that assess­ment. That also is the role of trained Board Cer­ti­fied radi­ol­o­gists—to know and advise about when CT scan­ning cre­ates a risk/ ben­e­fit ratio strongly in a patient’s favor.

Remem­ber par­ents, dis­cussing the risks of CT with your health care provider should cer­tainly be done, but be sure to get the full set of facts before refus­ing care that may save and extend a child’s life.

Monitoring Cumulative Dose from Multiple CT Scans

new study pre­sented at the Amer­i­can Roent­gen Ray Soci­ety (AARS) meet­ing brought atten­tion to another key point in radi­a­tion dose reduc­tion. Cur­rently, a major­ity of the focus on cut­ting CT scan radi­a­tion is cen­tered on dosage lev­els, but it is also impor­tant to mon­i­tor cumu­la­tive dosage in patients receiv­ing mul­ti­ple scans. While gov­ern­ment and indus­try are increas­ingly focused on sin­gle CT scan dosage reduc­tion (which is great news!), there is a lesser con­cern for decreas­ing the over­all num­ber of CT scans for patients.

The research tracked the amount of repeated CT exams per­formed on patients in order to cal­cu­late cumu­la­tive radi­a­tion dosage. Some of the results are shock­ing. The study iden­ti­fied a group of patients from the test pop­u­la­tion under­go­ing more than 20 med­ical imag­ing exams in one year, and as a result, being exposed to high cumu­la­tive dosage—more than 300 mSv per annum!  In fact, one patient received 70 dif­fer­ent scans in one year!

This is, of course, some­thing we are work­ing to mit­i­gate con­tin­u­ously. Europe (EEU) has been track­ing the cumu­la­tive dose of its cit­i­zens for about 10 years—by law! This is cer­tainly a good thing for patients and in the U.S, we are begin­ning efforts towards this direc­tion. Sev­eral prod­ucts are now avail­able that serve as a repos­i­tory for dose from devises and par­tic­u­lar pro­to­cols, to keep track for indi­vid­ual patients (includ­ing cumulative).

We recently pur­chased such a prod­uct (Dose­WatchGE Health­care) which will be inte­grated with our RIS and con­nected to every radi­a­tion emit­ting device in our med­ical cen­ter. This prod­uct will pick up cases of unusu­ally high cumu­la­tive dose in patients, but also iden­tify pro­to­cols which have high dose or devices which are emit­ting high dose. We are look­ing for­ward to imple­ment­ing Dose­Watch a few months from now.

Be sure to check back reg­u­larly as we doc­u­ment our expe­ri­ence with the product.

Emphysema Found on CT Scans Points to Increased Lung Cancer Risk

That there are strong asso­ci­a­tions between smok­ing and emphy­sema and smok­ing and lung can­cer is well estab­lished. There­fore, it’s of lit­tle sur­prise that a report from Lung Can­cer finds emphy­sema that is vis­i­ble to radi­ol­o­gists from CT scans is cor­re­lated with an increased risk of lung cancer.

How­ever, these results were only dis­cov­ered when the emphy­sema was read by radi­ol­o­gists— and not by com­puter inter­pre­ta­tion. Researchers point out that radi­ol­o­gists and auto­mated com­puter soft­ware likely detect dif­fer­ent types of emphy­sema– with only doc­tors appear­ing to detect the type of emphy­sema asso­ci­ated with lung can­cer. This clearly high­lights the “intu­ition” fac­tor in scan inter­pre­ta­tion by expe­ri­enced radiologists—a fac­tor not yet evi­dent in intel­li­gent computers!

Patients that are found to have emphy­sema detected by CT scans are already at an increased risk of devel­op­ing lung can­cer and should quit smok­ing as soon as pos­si­ble. It is inter­est­ing to remem­ber that before cig­a­rette smok­ing became wide­spread, both lung can­cer and emphy­sema were exceed­ingly rare dis­eases. Those high risk patients should explore the ben­e­fits of lung can­cer screen­ing and lung can­cer screen­ing programs.

For more infor­ma­tion on the ben­e­fits of lung can­cer screen­ing, please see here.

Further Validation: American Lung Association Supports CT Screening!

Another major orga­ni­za­tion has joined the U.S. National Can­cer Insti­tute to sup­port CT lung can­cer screen­ing as a life sav­ing pro­ce­dure! Recently, the Amer­i­can Lung Asso­ci­a­tion updated its rec­om­men­da­tions to sup­port low-dose CT lung screen­ing for smok­ers and for­mer smokers.

Lung can­cer con­tin­ues to be the lead­ing cause of death in the U.S., with more than 150,000 deaths annu­ally and a five year sur­vival rate as low as 15 per­cent. How­ever, research from the US National Can­cer Institute’s Lung Can­cer Screen­ing Trial gives promis­ing hope. The study found that low-dose CT can reduce mor­tal­ity rates by at least 20 per­cent among smok­ers and for­mer smok­ers. Other pub­lished reports have esti­mated even higher rates of mor­tal­ity gains! Accord­ing to the LCST, indi­vid­u­als between the ages of 55 and 74 years who are cur­rent or for­mer smok­ers of at least 30 pack-years and have no his­tory of lung can­cer are ideal can­di­dates for lung can­cer screen­ing with CT.

Cur­rently, besides never smok­ing, low-dose CT screen­ing is the only viable option for sig­nif­i­cantly reduc­ing the risk of lung can­cer. The ALA’s rec­om­men­da­tion of this med­ical imag­ing exam is an impor­tant step toward the devel­op­ment of wide­spread population-based CT screen­ing pro­gram through the U.S.

The ALA joins the National Com­pre­hen­sive Can­cer Net­work, the first major pro­fes­sional orga­ni­za­tion to rec­om­mend low-dose lung can­cer screen­ing last fall.

For more infor­ma­tion on fac­tors that may effect the wide­spread imple­men­ta­tion of lung can­cer screen­ing, see this post on low-cost screening.

Is Low-cost a Benefit for Lung Cancer Screening?

Is low-cost an added ben­e­fit to wide­spread lung can­cer screen­ing? Accord­ing to this arti­cle, from April’s Health Affairs—yes!  The study on this much debated about topic asserts that rou­tine CT lung can­cer screen­ing of high-risk indi­vid­u­als would save thou­sands of lives annu­ally for less than one dol­lar a month per patient, if imple­mented through­out the US. Accord­ing to these fig­ures, the cost of low-dose lung can­cer screen­ing could be less than that for both breast can­cer screen­ing and col­orec­tal can­cer screening.

As we’ve pointed out, lung can­cer screen­ing is effec­tive and life sav­ing.  For high– risk patients, those who are mul­ti­ple pack year smok­ers for 25 years or more, screen­ing pro­vides sig­nif­i­cant ben­e­fits. For these indi­vid­u­als, low-dose CT screen­ing reduces the num­ber of lung can­cer deaths by 20 percent!

Despite this, wide­spread lung can­cer screen­ing has yet to be imple­mented nation­wide, largely due to cost. This study reports inter­est­ing and encour­ag­ing data about wide­spread imple­men­ta­tion of the pro­ce­dure, though. How­ever, we must remem­ber that there are also rep­utable arti­cles which report much higher cost num­bers when adjusted for quality-life-years saved. It is nec­es­sary to take these stud­ies into account, too.

Looks like the jury may still be out on this one!

Choosing Wisely Campaign: ACR’s Recommendations Accurate!

The Choos­ing Wisely Cam­paign is a recent ini­tia­tive of the ABIM Foun­da­tion to encour­age physi­cians and patients to take a sec­ond look at tests and pro­ce­dures that may be unnec­es­sary… and poten­tially, harm­ful. The Amer­i­can Col­lege of Radi­ol­ogy was one of nine US spe­cialty soci­eties that devel­oped lists of the Five Things Physi­cians and Patients Should Question.

See the ACR’s out­lined rec­om­men­da­tions of the pro­ce­dures that should be uti­lized less in radi­ol­ogy practices:

• Imag­ing for uncom­pli­cated headache, absent spe­cific risk fac­tors for struc­tural dis­ease or injury.
• Imag­ing for sus­pected pul­monary embolism (PE) with­out mod­er­ate or high pretest prob­a­bil­ity of PE.
• Pre­op­er­a­tive chest x-rays with­out spe­cific rea­sons due to patient his­tory or phys­i­cal exam.
• CT to eval­u­ate sus­pected appen­dici­tis in chil­dren until ultra­sound is con­sid­ered an option.
• Follow-up imag­ing for adnexal (repro­duc­tive tract) cysts 5 cm or less in diam­e­ter in reproductive-age women.

All five of these rec­om­men­da­tions are ones that I would cer­tainly agree with. In fact, I wouldstrongly empha­size that CT for pos­si­ble pul­monary embolism in young women be avoided unless there are clin­i­cal cri­te­ria which raise sus­pi­cion to at least mod­er­ate level. Addi­tion­ally, ultra­sound is a great modal­ity to check for appen­dici­tis in chil­dren, espe­cially those that are young and/ or thin.

For the full rec­om­men­da­tions by the ACR, please see here. Remem­ber, informed patients are an inte­gral part of the Choos­ing Wisely campaign.

New Reconstruction Algorithm Could be Answer to High Radiation Dosage and IBF Correlation

recent study on the high accu­mu­la­tion of radi­a­tion dosages in young patients with inflam­ma­tory bowel dis­ease brings light to a topic of con­cern for any CT prac­ti­tioner. This research, pub­lished in Clin­i­cal Gas­troen­terol­ogy and Hepa­tol­ogy, con­cludes that patients with diges­tive dis­or­ders may be exposed to sig­nif­i­cant radi­a­tion doses from abdom­i­nal CT over time.

It attests that the radi­a­tion lev­els among patients with gas­troin­testi­nal dis­or­ders have risen over the last few years. And, mostly due to repeat scan­ning, over 50 per­cent of the patients with cumu­la­tive expo­sure exceed­ing the 90th per­centile, par­tic­u­larly those with IBD, were younger than 35 years old.

Here at UW, we recently acquired a new CT imag­ing recon­struc­tion algo­rithm– VEO or model based iter­a­tive recon­struc­tion.  This low­ers radi­a­tion dose 60 to 80 per­cent below that of ASIR recon­struc­tion and 90 per­cent below that of FBP. The only dis­ad­van­tage of VEO? It takes about 30 to 40 min­utes per case to recon­struct because it is com­pu­ta­tion­ally much more intensive.

In plan­ning how to begin using VEO, one of the first patient groups we’ve focused on is young patients with IBD. The use of this tech­nol­ogy will help lower the accu­mu­la­tive radi­a­tion dose lev­els among those patients who require reg­u­lar abdom­i­nal screening.

Obesity and CT Scan Radiation—Technology Helps to Cut Exposure

Most med­ical equip­ment is not designed for obese patient opti­miza­tion, includ­ing diag­nos­tic imag­ing modal­i­ties. Due to this, over­weight and obese indi­vid­u­als are sub­ject to higher lev­els of radi­a­tion dur­ing rou­tine CT scans and X-rays.

A recent study, pub­lished in the Jour­nal of Physics in Med­i­cine and Biol­ogy, cal­cu­lated exactly how much addi­tional radi­a­tion over­weight patients are exposed to from CT scans. Accord­ing to the research, obese men and women receive 62 per­cent and 59 per­cent more radi­a­tion dur­ing CT scans than nor­mal weight indi­vid­u­als. How­ever, new tech­nol­ogy can help con­trol that percentage.

Phan­toms, real­is­tic 3-D com­puter mod­els of over­weight and obese men and women, can now be used to deter­mine the risk of radi­a­tion scans on dif­fer­ent body types.  The use of var­i­ous sized phan­toms to study CT dose dis­tri­b­u­tion within the human body is a very sci­en­tific approach when con­sid­er­ing the effects of CT. This tech­nol­ogy will be able to accu­rately tell radi­ol­o­gists how much radi­a­tion patients receive from dif­fer­ent devices so that they can make the safest and opti­mal choice for the patient.

Notice, this arti­cle high­lights the sig­nif­i­cant increase in radi­a­tion dose—espe­cially in obese patients—from increas­ing kVp to 140. At UW, our tech­nol­o­gists use 140 kVP for CT only after hav­ing a con­ver­sa­tion with a radi­ol­o­gist about each spe­cific case.

Learn more about the use of phan­toms for obese patients here.

New Research Further Dispels Fear of Over Diagnosis in CT Screening

Accord­ing to a new study based on the Inter­na­tional Early Lung Can­cer Action Pro­gram (I-ELCAP), lung can­cers iden­ti­fied in low-dose CT screen­ing pro­grams are sim­i­lar to those iden­ti­fied by non– screen­ing means. The research results, which were released on March 27 in Radi­ol­ogy, fur­ther alle­vi­ate con­cerns that can­cers detected through low– dose CT screen­ing are less aggres­sive than those found through other means, and there­fore demand less atten­tion and resources.  In fact, the fre­quency of small-cell car­ci­noma and ade­no­car­ci­noma were sim­i­lar for can­cers detected through screen­ing pro­grams and out­side the screen­ing set­ting.

This study is another brick in the wall of evi­dence build­ing for the value of low radi­a­tion dose CT lung can­cer screen­ing in high risk asymp­to­matic smok­ers. Regard­less of whether nod­ules are solid or “ground glass” (non-solid), growth occurs that is sim­i­lar in the screened pop­u­la­tions and in those detected of hav­ing lung can­cer due to symptoms.

While it is true we do not yet have a data-based analy­sis of costs ver­sus qual­ity life years saved, the evi­dence that screen­ing is worth­while con­tin­ues to become stronger. “The CT scan­ners we have now are really phe­nom­e­nal,” with res­o­lu­tion that con­tin­ues to improve as the radi­a­tion dose falls, “so that the amount of infor­ma­tion you can get out of them for emphy­sema, for coro­nary artery risks, and so on, con­tin­ues to increase,” says Dr. Clau­dia Hen­schke, lead author of this study.

She goes on to point out that can­cers detected via low dose CT screen­ing “are real can­cers that would kill you if they weren’t dis­cov­ered early, so it kind of under­scores again the data that we had shown in ELCAP and that NLST (National Lung Screen­ing Trial) has shown — that screen­ing for lung can­cer saves lives.” And that is the key takeaway.

Low-dose Lung Cancer Screening Too Costly? No…

I recently came across a study that ques­tioned the cost– effec­tive­ness of low-dose CT scans for lung can­cer screen­ing. As I’ve dis­cussed before, there is suf­fi­cient and sound research val­i­dat­ing that among high– risk indi­vid­u­als, low-dose lung can­cer screen­ing is a life sav­ing process. How­ever, this arti­cle claims that the med­ical imag­ing pro­ce­dures may be too costly for the United States, “a nation strug­gling to con­trol grow­ing health care costs, even though some lives would be saved.”

This arti­cle clearly shows how charges relate to the exe­cu­tion of health­care. At stan­dard charges, screen­ing CT of patient’s at high risk for lung can­cer may not be cost effec­tive. But, if these are regarded as add-on incre­men­tal cases and are priced at mar­ginal cost (approx­i­mately $200), the screen­ing equa­tion may change and become finan­cially viable from society’s prospective.

As with any screen­ing pro­gram, the first caveat is to “do no harm” — hence an ultra-low dose CT tech­nique would be advan­ta­geous. Sim­i­larly, fig­ur­ing out how to keep the cost way down will be crit­i­cal. I think we can.…

The Truth about CT Exposure: 1980 to 2012

recent arti­cle pub­lished in CA: A Can­cer Jour­nal for Clin­i­cians states that edu­ca­tion of refer­ring physi­cians, more assertive radi­ol­o­gists, and an increased use of health­care IT are the keys to reduc­ing patient expo­sure to radiation.

While these asser­tions may be true, the arti­cle also touched on ris­ing radi­a­tion expo­sure due, pri­mar­ily, to CT scans. Since the early 1980s, the esti­mated per capita dose from med­ical radi­a­tion in the US has increased sig­nif­i­cantly. But this isn’t the whole story…

While it is true that med­ical radi­a­tion from CT has increased markedly since 1980, so has the ben­e­fit to health from CT. We no longer do “exploratory surgery” for exam­ple, in order to sort out com­plex diag­nos­tic imag­ing chal­lenges. The false neg­a­tive rate from Appen­dix surgery has plum­meted. And can­cer diag­no­sis rates over­all are declin­ing while can­cer cure rates have gone up sub­stan­tially, par­tic­u­larly in the last 5 years.

Mean­while, the radi­a­tion dose per CT scan has gone down dra­mat­i­cally as the prin­ci­ples of low-dose CT con­tinue to be bet­ter under­stood and imple­mented. Scans that used to require 25 mSv of radi­a­tion are now being done for 20% of that amount. While neg­a­tive effects from low dose radi­a­tion have never bee proven (below 50 mSv), we still strive to keep our doses as low as possible.

So the issue is not radi­a­tion cost, but cost/benefit ratio. Dri­ving a car is dan­ger­ous too, but we accept the cost/benefit ration. For CT that ratio is much better!

The Image Wisely Campaign: Take the Pledge Today!

If you work in radi­ol­ogy, chances are that you are aware of the Image Wisely cam­paign. Cre­ated by the Joint Task Force on Adult Radi­a­tion Pro­tec­tion (made up of mem­bers of the Amer­i­can Col­lege of Radi­ol­ogy and the Radi­o­log­i­cal Soci­ety of North Amer­ica), the Amer­i­can Asso­ci­a­tion of Physi­cists in Med­i­cine (AAPM), and the Amer­i­can Soci­ety of Radi­o­logic Tech­nol­o­gists (ASRT), the cam­paign strives to lower the amount of radi­a­tion used in med­ically nec­es­sary imag­ing stud­ies and to elim­i­nate unnec­es­sary procedures.

I am proud to say that I have taken the pledge, with over 12,000 other health care pro­fes­sion­als, to image wisely by opti­miz­ing the use of radi­a­tion when imag­ing patients.

The Image Wisely cam­paign is a very impact­ful under­tak­ing which deserves the atten­tion and par­tic­i­pa­tion from all of us in Radi­ol­ogy. The pledge raises aware­ness and com­mit­ment to max­i­miz­ing the ratio between infor­ma­tion obtained for min­i­mal dose uti­liza­tion. In addi­tion, the pledge assists with low dose pro­to­cols and good prac­tices, plus equip­ment oper­a­tion is included.

I urge all to read the web­site closely and under­stand the goals of the cam­paign. Then take the pledge today!

More Infor­ma­tion on the Image Wisely Campaign.

CT Lung Screening and Follow-up Protocol

Research pub­lished in this month’s Amer­i­can Jour­nal of Roentgenol­ogy reported excel­lent results on a pro­to­col for work­ing up patients with nod­ules found in CT lung screen­ing. Ever since the National Lung Screen­ing Trial showed a 20% mor­tal­ity reduc­tion among high-risk patients screened for the dis­ease, crit­i­cism has been vocal­ized due to the poten­tially large num­ber of false-positive results fol­low­ing diag­nos­tic imag­ing inves­ti­ga­tions. Though the pos­si­bil­ity of find­ing can­cer out­weighs the risk of false pos­i­tives, the researchers argued that false-positive results could poten­tially increase the risks and costs of screen­ing, dimin­ish­ing the ben­e­fit of early can­cer detection.

This study, which required par­tic­i­pants with­out a his­tory of can­cer to have smoked a min­i­mum of 10 pack-years, con­cluded with pos­i­tive results. Accord­ing to the research, the algo­rithm pro­duced low false-positive rates, and could make the estab­lish­ment of large-scale CT screen­ing pro­grams more feasible.

Follow-up CT pro­to­cols in lung can­cer screen­ing - once a find­ing is dis­cov­ered and needs to be eval­u­ated over time or even just rou­tinely on a sched­ule — is one area ripe for ultra low-dose CT tech­nique. With this tech­nique, we really can see doses reduced by 40 — 80% among these appli­ca­tions! Accept­ing higher noise in images, very low-dose kVp (in the 80–100 range), and aggres­sive appli­ca­tion of iter­a­tive recon­struc­tion tech­niques can pro­duce diag­nos­tic CT results at breath­tak­ingly low doses.

Lung CT Screening a Top Cancer Advancement of 2011!

As the war on can­cer con­tin­ues, a group of U.S. oncol­o­gists picked its “Top Five” most essen­tial advances in can­cer care, as reported by Health­Day news. I’m pleased to announce that CT-based lung can­cer screen­ing is listed as one of the major advances for 2011.

The report, pub­lished in the Jour­nal of Clin­i­cal Oncol­ogy, placed only tar­geted drug ther­apy above CT-based lung can­cer screen­ing. Both advance­ments will be major game chang­ers for can­cer care. The report con­firms that the U.S. National Can­cer Insti­tute found that screen­ing smok­ers and for­mer smok­ers with a CT chest scan was “dra­mat­i­cally bet­ter than the chest X-ray.”

There now is no ques­tion about this! In high risk heavy smoker pop­u­la­tions, low dose CT– lung can­cer screen­ing saves lives… and quite a few. The chal­lenge now is get­ting our health­care deliv­ery sys­tems to incor­po­rate this approach into rou­tine pre­ven­ta­tive med­ical practices.…but only for high risk indi­vid­u­als. We need to make these scans easy to obtain, fast to per­form, very low in radi­a­tion, cov­ered in health plans, and inexpensive.

The good news is that all of these things are pos­si­ble. Turn­ing CT-lung can­cer screen­ing into a reg­u­lar prac­tice for in-need indi­vid­u­als is very do-able!

AAPM Position Statement on Radiation Risks!

state­ment was recently released by the Amer­i­can Asso­ci­at­ing of Physi­cists in Med­i­cine regard­ing how extremely low the risk of harm from radi­a­tion in diag­nos­tic imag­ing stud­ies is. Indeed, they state, it may be non-existent. I am absolutely delighted to finally see a state­ment like this in print, espe­cially com­ing from the AAPM, a rep­utable and dig­ni­fied organization.

In fact, this kind of state­ment has been needed for some time:

“Dis­cus­sion of risks related to radi­a­tion dose from med­ical imag­ing pro­ce­dures should be accom­pa­nied by acknowl­edge­ment of the ben­e­fits of the procedures.”

This sen­tence urges all providers, and even inves­tiga­tive news reporters, to do the respon­si­ble thing — dis­cuss risks and ben­e­fits at the same time, in a bal­anced way, using lan­guage and con­cepts that patients can under­stand and grasp. Under­stand­ing extremely small risks (so small as to be poten­tially nonex­is­tent) is very chal­leng­ing for most of us — so it requires extra time and effort.

“Risks of med­ical imag­ing at patient doses below 50 mSv for sin­gle pro­ce­dures or 100 mSv for mul­ti­ple pro­ce­dures over short time peri­ods are too low to be detectable and may be nonex­is­tent.“

Some­one finally stood up and said it! The non-detectability of extremely low risk has stood the test of time. The non-existent risk pos­si­bil­ity may be true and should be included in any discussion.

“Pre­dic­tions of hypo­thet­i­cal can­cer inci­dence and deaths in patient pop­u­la­tions exposed to such low doses are highly spec­u­la­tive and should be dis­cour­aged. These pre­dic­tions are harm­ful because they lead to sen­sa­tion­al­is­tic arti­cles.“

It is def­i­nitely pos­si­ble that sen­sa­tion­al­ism may have resulted in patient harm — by inap­pro­pri­ately scar­ing some patients away from imag­ing. These med­ical imag­ing treat­ments might have helped them, whereas not get­ting the imag­ing might have harmed them by deny­ing access to the diag­noses lead­ing to cor­rect and swift treatment.

In black and white: pre­dicted can­cer risk from these low doses is hypo­thet­i­cal and resul­tant deaths are only speculation.

UW and the ACR Dose Registry

The Amer­i­can Col­lege of Radiology’s (ACR) Dose Index Reg­istry pilot project has already amassed a num­ber of stud­ies, accord­ing to a pre­sen­ta­tion given at RSNA 2011. The pro­gram strives to accu­rately track CT radi­a­tion dose in order to estab­lish national bench­marks, allow­ing prac­tices to mon­i­tor radi­a­tion dose expo­sure and com­pare pat­terns. Although only launched in June 2011, the Dose Index Reg­istry is already up and run­ning and any med­ical imag­ing facil­ity can now reg­is­ter for the program.

The Uni­ver­sity of Wash­ing­ton was the sec­ond insti­tu­tion to sign up for the ACR Dose Index Reg­istry. Using a Dose­Watch prod­uct, we will get real time infor­ma­tion on every CT scan and every patient scanned, includ­ing the dose each machine puts out in gen­eral, and dosage each patient is exposed to per scan and over time. This infor­ma­tion then gets for­warded to the cen­tral reg­istry main­tained by the ACR for mon­i­tor­ing and for com­par­i­son purposes.

This should be a very pow­er­ful mon­i­tor­ing pro­gram and a big boost to safety. We are glad to take part in the pro­gram and look for­ward to the insights that being part of the Dose Index Reg­istry can provide!

NCCN Confirms Importance of Lung Cancer Screening

Recently, the National Com­pre­hen­sive Can­cer Net­work has come for­ward in favor of lung can­cer screen­ing with low-dose CT. The NCCN is the first pro­fes­sional orga­ni­za­tion to per­form the com­pre­hen­sive review and update their rec­om­men­da­tions to pro­mote lung can­cer screening.

This update fur­ther val­i­dates the key con­cept that high risk patients ben­e­fit from screen­ing. High risk patients for lung can­cer diag­noses are those who are mul­ti­ple pack year smok­ers for 25 of more years. For these indi­vid­u­als, low– dose CT screen­ing reduces the num­ber of lung can­cer deaths by 20 percent.

While we don’t really know the full cost of a screen­ing pro­gram — such as the costs of work­ing up false pos­i­tive CT find­ings,  the ben­e­fit in lives saved seems to jus­tify con­sid­er­ing screen­ing now.

For­tu­nately, the CT tech­nique for screen­ing is low dose and involves low radi­a­tion dosage.

RSNA 2011 Relections

RSNA (Radi­o­log­i­cal Soci­ety of North Amer­ica) is the largest annual trade show in the world, with about 55,000 peo­ple in atten­dance for the 6 day event in Chicago, Illi­nois. The expo includes a large num­ber of pre­sen­ta­tions and courses on sci­ence and mod­ern radi­ol­ogy.

RSNA 2011’s two main themes were lower radi­a­tion dose in diag­nos­tic radi­ol­ogy imag­ing (espe­cially CT) and new tech­nol­ogy. For lower dose, there was much mate­r­ial on tai­lor­ing a CT scan exactly to an indi­vid­ual patient — based on their body size, their car­diac out­put, their dis­ease process, or the type of diag­nos­tic chal­lenge. Addi­tion­ally, a lot about new iter­a­tive recon­struc­tions in CT — both sta­tis­ti­cal and model based, was pre­sented. Either method low­ers dose a lot, but model based results in low­ered radi­a­tion expo­sure by up to 80%.

New tech­nol­ogy pre­sen­ta­tions and courses cov­ered a range of top­ics includ­ing dual energy CT for bet­ter tis­sue char­ac­ter­i­za­tion, and the com­bi­na­tion of imag­ing modal­i­ties in one plat­form — like SPECT/CT, or PET/MR. These com­bined modal­i­ties may pro­vide a bet­ter com­bi­na­tion of dis­ease iden­ti­fi­ca­tion plus pre­cise localization.

In all, RSNA 2011 offered great insights and inter­est­ing pre­sen­ta­tions. Did you attend? Share your thoughts below!

Dual– Energy CT: Less Radiation, Higher Image Quality

recent pre­sen­ta­tion at the 2011 Inter­na­tional Soci­ety for Com­puter Topog­ra­phy (ISCT) meet­ing in San Fran­cisco high­lighted the effec­tive­ness of using dual– energy CT for abdom­i­nal imag­ing. This CT– tech­nique has become more promis­ing for uncov­er­ing cer­tain pathol­ogy that has oth­er­wise been hid­den by tra­di­tional diag­nos­tic imag­ing procedures.

Dual– energy CT– by what­ever tech­nol­ogy — can be con­fig­ured to employ less radi­a­tion than sin­gle energy CT. But for some spe­cific appli­ca­tions, it pro­duces more diag­nos­tic and spe­cific infor­ma­tion. Dual– energy CT cur­rently may be the best radi­ol­ogy tech­nique for char­ac­ter­iz­ing uri­nary tract stones to their chem­i­cal com­po­si­tion (which deter­mines whether med­ical, shock­wave, or laser ther­apy will be required), char­ac­ter­iz­ing small renal masses, and char­ac­ter­iz­ing liver masses into cyst ver­sus tumor.

Addi­tion­ally, dual– energy CT may apply to bet­ter detect­ing min­i­mal liver tumors, low­er­ing the amount of iodine needed for CT angiograms, and cre­at­ing vir­tual non– con­trast scans. The lat­ter may reduce the over­all CT radi­a­tion dose of a multi– phase study by 20 to 50 percent!

While dual– energy is still rel­a­tively new to the field, it is clear that it is a promis­ing tech­nique for CT dose reduc­tion, while main­tain­ing imag­ing qual­ity. Fur­ther research and test­ing will be con­clu­sive of the absolute ben­e­fits of dual– energy CT.

RSNA 2011: Don’t Miss Out!

The RSNA 2011 con­fer­ence marks the 97th Sci­en­tific Assem­bly and Annual Meet­ing. This event, the world’s pre­mier med­ical meet­ing for radi­o­logic pro­fes­sion­als, is being held on Novem­ber 27 through Decem­ber 2 at the McCormick Place in Chicago. The annual con­fer­ence includes unpar­al­leled edu­ca­tion and pro­fes­sional devel­op­ment, net­work­ing oppor­tu­ni­ties, and a cut­ting– edge tech­ni­cal exhibition.

I will be involved in a num­ber of events, both as a pre­sen­ter and an author. The pre­sen­ta­tions that I will be involved in include:

• Pre­sen­ter– Hot Top­ics: Dual– Energy CT on Tues­day, Novem­ber 29 from 7:15 am to 8:15 am.

• Pre­sen­ter– Refresher: Mind Your Own Busi­ness! Required Busi­ness Skills for Your First Job on Thurs­day, Decem­ber 1 from 4:30 pm– 6:00 pm.

• Author/ Par­tic­i­pant– Gas­troin­testi­nal Series: Sci­en­tific For­mal Pre­sen­ta­tion (Dual-Energy CT of Hyper­vas­cu­lar Liver Lesions: Eval­u­a­tion of Lesion Contrast-to-Noise with Dif­fer­ent Mono­chro­matic keV Recon­structed Images) on Mon­day, Novem­ber 28 from 9:50 am to 10:00 am.

• Author/ Par­tic­i­pant– ISP– Health Ser­vices, Pol­icy, and Research– Sci­en­tific For­mal Pre­sen­ta­tion (Patient Knowl­edge and Per­cep­tions about Radi­a­tion from Diag­nos­tic Imag­ing) on Mon­day, Novem­ber 28 from 3:30 pm to 3:40 pm.

• Author/ Par­tic­i­pant– Neu­ro­ra­di­ol­ogy Series: Stroke Imag­ing– Sci­en­tific For­mal Pre­sen­ta­tion (Changes in the Mea­sured Size of Ath­er­o­scle­rotic Plaque Cal­ci­fi­ca­tions in Dual-Energy CT of ex Vivo Carotid Endarterec­tomy Spec­i­mens: The Affect of Dif­fer­ent Mono­chro­matic keV Image Recon­struc­tions) on Wednes­day, Novem­ber 30 from 11:00 am to 11:10 am.

For more infor­ma­tion about RSNA 2011 and the pre­sen­ta­tions that I’ll be involved in, please see the meet­ing pro­gram.

UW’s Team Approach to Radiation Dosage Reduction

A recent arti­cle pub­lished in the Amer­i­can Jour­nal of Roentgenol­ogy touched on the impor­tance of tak­ing a team wide approach to CT radi­a­tion dose reduc­tion. While CT only account for about 15 per­cent of diag­nos­tic imag­ing exams, it is respon­si­ble for con­tribut­ing up to 70 per­cent of radi­a­tion dosage to the pop­u­la­tion, accord­ing to this study. Hence, the rea­son why it’s imper­a­tive to have the whole team on board when it comes to reduc­ing CT scan radi­a­tion expo­sure in patients.

Ensur­ing that CT exams are appro­pri­ate is a crit­i­cal com­po­nent of over­all dose reduc­tion. At UW, we use a com­put­er­ized Deci­sion Sup­port pro­gram, which acts at the point of Com­put­er­ized Physi­cian Order Entry (CPOE) to check appro­pri­ate­ness. Radi­ol­o­gists also double-check at the time of elec­tronic protocoling.

At the time of the scan, the use of exter­nal body shields — includ­ing breast shield­ing — is impor­tant. Addi­tion­ally, patient cen­ter­ing in the gantry is crit­i­cal and can lower dose by as much as 40% com­pared to off-center exams. The rou­tine use of iter­a­tive recon­struc­tion tech­nique — com­pared to the older FBP — can fur­ther sub­stan­tially lower dose.

By hav­ing low– dose pro­to­cols and pro­ce­dures set in place, we can be sure that we are pro­vid­ing our patients with the safest, most effec­tive imag­ing procedures!

Abdominal CT Scans: How Low a Dose is Low Enough?

I was recently asked the ques­tion: “How low is low enough for CT?” With the risks of CT scans, the answer is: as low as you can go with­out sig­nif­i­cantly com­pro­mis­ing diag­nos­tic power.

Some­times we do very noisy CT exams at extremely low doses, know­ing that we may miss a 1 mm ureteral stone. How­ever, we accept that pos­si­bil­ity since such a small stone may not be clin­i­cally relevant.

Our rou­tine abdominal/ pelvic exam is nois­ier than most of the CT exams we see referred in — but we delib­er­ately chose to become accus­tomed to the higher noise lev­els (even when using  iter­a­tive recon­struc­tion) in order to min­i­mize CT radi­a­tion dose. Thus, our doses are 40 per­cent lower than those on some of the CT scans we see being admin­is­tered at many other places. There is no evi­dence we have com­pro­mised diag­nos­tic power with our reduced dosage CT scans.

In today’s world, the 1–3 mSv car­diac CT is com­mon­place. In the near future, a CT of the abdomen and pelvis (40 cm of Z axis) using 0.6 mSv will soon be com­mon­place with the arrival of model based iter­a­tive recon­struc­tion. With MBIR recently becom­ing avail­able in the United States we will soon see dose reduc­tions of up to 80 percent!

Professional Recommendations for Low Dose Optimization

I came across an arti­cle from the Jour­nal of the Amer­i­can Col­lege of Radi­ol­ogy on a num­ber of rec­om­men­da­tions for opti­miz­ing patient dose level in chest CT scans, the third most com­monly per­formed CT exam in the country.

As the arti­cle points out, the lungs are an ideal organ for low dose radi­a­tion CT scans. Some of the rec­om­men­da­tions offered include:

  • Doc­tors should ensure that patients under­stand all instruc­tions fully, includ­ing when to hold their breath and how much move­ment is permitted.
  • Auto­mated expo­sure con­trol (AEC) tech­niques should be used as often as pos­si­ble to assist with breath­ing in chil­dren and adults.
  • Iter­a­tive recon­struc­tion tech­niques reduce radi­a­tion dose expo­sure sub­stan­tially and should be per­formed as often as possible.
  • Cen­ter­ing patients in the gantry isocen­ter avoids exces­sive scan length dose. Addi­tion­ally, CT scans should only be per­formed on the area of indication.
  • Read­ing thicker sec­tions ensures CT scan radi­a­tion risk reduc­tion, while allow­ing fine details to be exam­ined in nosier, thicker sec­tions. This pro­ce­dure should be uti­lized by imag­ing professionals.
  • All CT scans should be done for a clin­i­cal and jus­ti­fi­able reason.

The tips and point­ers in this arti­cle are all good tools for low­er­ing patient radi­a­tion dose in chest CT. We have found that the use of iter­a­tive recon­struc­tion is a big help — low­er­ing dose by as much as 40%. Now that model based iter­a­tive recon­struc­tion has recently become avail­able in the USA (GE’s ver­sion is called VEO), we can look for dose reduc­tions of more like 80%!

CT Scans in the ER: Generally a Safe Practice

A recent study pub­lished in the Annals of Emer­gency Med­i­cine on the rapid increase in CT scans being per­formed in Emer­gency Rooms (ER) paired with the decline in hos­pi­tal admis­sion rates between 1996 and 2007, got me think­ing.  Dur­ing this time, the num­ber of CT scans being per­formed increased by 330 per­cent, while the rate of those admit­ted fol­low­ing a CT scan decreased from 26 per­cent in 1996 to 12.1 per­cent in 2007. Does this mean that more patients are receiv­ing unnec­es­sary radi­a­tion expo­sure? Well… not necessarily.

The arti­cle points out a con­flict about the use of CT in ER patients. Remem­ber that prac­tic­ing med­i­cine in an ER is very dif­fer­ent from a physician’s office. Patients are more acutely ill and ER con­ges­tion can be marked. Plus, time spent in the ER is very expen­sive.
In our study of patients pre­sented to an ER with low to mod­er­ate risk chest pain, we found that a neg­a­tive triple rule out CT resulted in short­en­ing the stay by over 20 hours and cut­ting the cost of the ER encounter by 50%. Fur­ther, dis­charg­ing a patient to home if their CT was neg­a­tive was a safe practice.

There­fore, under the right cir­cum­stances, the use of CT in ER patients can be very effec­tive. Our chal­lenge is — through out­comes research — find­ing those right circumstances.

For more infor­ma­tion on emer­gency med­i­cine at UW, please see here.

Frequent CT Scanning Not Linked to Cancer Diagnosis

study pub­lished in a recent issue of the Jour­nal of Amer­i­can Col­lege of Radi­ol­ogy asserts that CT –induced can­cers are more likely to occur amongst rarely scanned young adults, as opposed to fre­quently scanned patients–the group that many assumed was at the high­est risk for radi­a­tion induced can­cer diag­noses.

It is still true that a def­i­nite rela­tion­ship between can­cer induc­tion and less than 100 mSv of radi­a­tion has never been proven. This is assumed, for safety’s sake — based on proven rela­tion­ships with much higher doses of radi­a­tion. Remem­ber, a typ­i­cal CT of the abdomen and pelvis in the mod­ern world is about 6–10 mSv.

The other vari­able that has never been proven is the assump­tion that the risk from mul­ti­ple scans which are widely spaced in time is addi­tive. In fact, we know that the body has tremen­dous capac­ity to heal and repair any kind of dam­age — so any dam­age from a sin­gle event of low dose radi­a­tion may be fully repaired before a sec­ond event occurs. Hence the effect may not be at all additive.

So… results like those found in this arti­cle are not surprising.

Noth­ing, how­ever, should lessen our vig­i­lance about striv­ing for as low a radi­a­tion dose as pos­si­ble for all med­ical diag­nos­tic imag­ing appli­ca­tions. In a world of unknowns (and pos­si­bly unknowable’s), that’s just com­mon sense.

Radical Breakthrough in the Drive toward Lower Dose

GE recently announced the intro­duc­tion of a break­through low– dose imag­ing recon­struc­tion tech­nol­ogy in Canada. This CT image recon­struc­tion tech­nol­ogy, called Veo, is the first Model– based Iter­a­tive Recon­struc­tion (MBIR) tech­nique.  The tech­nol­ogy is a response to radi­ol­o­gists’ demand for a tech­nique that max­i­mizes CT image clar­ity and qual­ity while opti­miz­ing the dosage level for patients’ safety.

MBIR is indeed a rad­i­cal break­through in the drive toward lower dose CTs. While very com­pu­ta­tion­ally inten­sive, this tech­nique allows marked reduc­tion in patient dose from CT (by up to 80% or greater), yet also pro­vides some improve­ment in spa­tial res­o­lu­tion with­out com­pro­mis­ing con­trast res­o­lu­tion. How could all that be pos­si­ble — seem­ingly defy­ing the laws of physics? The answer is in the much faster com­pu­ta­tional speeds of the mod­ern com­puter chip.

The Uni­ver­sity of Wash­ing­ton will be part of the group assess­ing the degree to which MBIR, com­mer­cially known as Veo, out­per­forms more tra­di­tional CT recon­struc­tion techniques.

Time Saved Does Not Justify Inaccuracy

A recent arti­cle on Time.com dis­cusses sit­u­a­tions where physi­cians may “bend the truth” in order to arrive at quicker results – in this case, the deci­sion to per­form an appendectomy.

CT scan­ning with­out oral con­trast for pos­si­ble appen­dici­tis gives up sev­eral per­cent­age points in accu­racy. A radi­ol­o­gist may mis­take a non-contrasted ter­mi­nal ileum for an inflamed appen­dix. And the ear­li­est sign of appen­dici­tis is called the arrow­head sign, which is con­trast in an ede­ma­tous appen­diceal ori­fice – can­not be detected with­out the con­trast. Many sur­geons take com­fort from the pres­ence of con­trast in the appen­dix as evi­dence that por­tion of the appen­dix is not obstructed and inflamed.

Sure you can cut cor­ners and save time. The ulti­mate time-saving cor­ner to cut is to not do a CT and just decide based on phys­i­cal exam plus lab results. The accu­racy of CT with­out con­trast is sim­i­lar to that approach. But if we do CT in order to get more accu­rate diag­no­sis, we need to have the CT do its best job in terms of accu­racy… which requires oral contrast.

In my opin­ion, the time saved by doing CT with­out oral con­trast def­i­nitely does not jus­tify the loss in accu­racy. Pres­sure to prac­tice this way comes from well inten­tioned folks who do not have to inter­pret CT exams them­selves, and stand by the results.

New Data on Lung Cancer Screening Shows Low Dose CT Saves Lives

Ear­lier this year, I wrote a blog entry about the news sur­round­ing an impor­tant study involv­ing CT and lung can­cer screen­ing. Now, the same study is mak­ing big head­lines again as stronger (final) find­ings have been released. Accord­ing to CNN, the study found that “low-dose CT screen­ing reduces the num­ber of lung can­cer deaths in high risk smok­ers by 20 percent.”

Here’s another inter­est­ing fact com­ing out of the lat­est data: In high-risk pop­u­la­tions, lung can­cer CT screen­ing can save a life for every 300 peo­ple screened. That’s more poten­tial lives saved than mam­mog­ra­phy, colonog­ra­phy and prostate can­cer screen­ing COMBINED!

The only hitch: lung can­cer CT screen­ing is not cov­ered by most insur­ance. How­ever, many hos­pi­tals and imag­ing cen­ters are offer­ing this ser­vice at attrac­tive rates for those who are will­ing to pay themselves.

An Interview with Dr. Mitsumori on Weight-based Selection of CT Parameters

The fol­low­ing is an inter­view I con­ducted with Dr. Lee Mit­sumori, Assis­tant Pro­fes­sor of Radi­ol­ogy at the Uni­ver­sity of Washington.

Dr. Shu­man: Please give us a brief overview of your work involv­ing weight-based selec­tion of CT parameters.

Dr. Mit­sumori: We have been inves­ti­gat­ing the use of body-size-dependent CT scan para­me­ters to opti­mize the radi­a­tion dose of each scan. Sev­eral imag­ing para­me­ters can be mod­i­fied at the time of the CT that can alter the amount of radi­a­tion of the scan (tube cur­rent, tube poten­tial, scan range, scan phases, image recon­struc­tion tech­niques). The chal­lenge is to adjust each so that the final set of patient images are of diag­nos­tic image qual­ity and were obtained with the low­est pos­si­ble radi­a­tion dose. The risk is that incor­rect set­tings or too aggres­sive dose reduc­tion can cre­ate a scan that is of poor image qual­ity that does not allow a cor­rect inter­pre­ta­tion. Cur­rent work at Uni­ver­sity of Wash­ing­ton Med­ical Cen­ter involves stud­ies com­par­ing dif­fer­ent CT image recon­struc­tion tech­niques (adap­tive iter­a­tive recon­struc­tion, model based iter­a­tive recon­struc­tion) that can sig­nif­i­cantly reduce CT image noise and how these can be best imple­mented in patient CT exams.

Dr. Shu­man: Why is weight an impor­tant con­cern regard­ing CT? How does weight affect CT?

Dr. Mit­sumori: A patient’s body size, as reflected by weight, affects two impor­tant fea­ture of a CT scan. The first is the amount of pho­tons needed to gen­er­ate an inter­pretable CT image. A CT is a pro­jec­tion tech­nique, where an x-ray source emits pho­tons that then pass through the sub­ject before being recorded by a detec­tor on the other side of the patient. Larger patients need more pho­tons with higher energy than smaller patients to cre­ate images that can be cor­rectly inter­preted. If the CT para­me­ters are not cor­rectly set and only a small num­ber of pho­tons are recorded by the detec­tor, the images cre­ated are noisy. If an image is too noisy, the inter­pret­ing physi­cian may not be able to see if a prob­lem or dis­ease process is present. Unfor­tu­nately, the more pho­tons used the higher the radi­a­tion expo­sure of the CT exam. While large patients are at risk for hav­ing noisy images, small patients can have scans done with para­me­ters selected for an aver­age sized patient, in which case too many pho­tons are used than what would be needed to cre­ate diag­nos­tic images. Thus, the impor­tance of match­ing the radi­a­tion dose (num­ber and energy of pho­tons emit­ted) with the patient’s body size to pre­vent non-interpretable stud­ies in larger patients, and avoid exces­sive radi­a­tion dose in the smaller patient.

The sec­ond fea­ture of a CT scan where patient size is impor­tant is in the amount of iod­i­nated con­trast needed for the scan. Iod­i­nated CT con­trast is injected intra­venously dur­ing the scan and improves the depic­tion of the dif­fer­ent organs and vas­cu­lar struc­tures in the body. With CT imag­ing, the use of con­trast greatly improves the radiologist’s abil­ity to dif­fer­en­ti­ate dis­eased (tumors, infec­tion, inflam­ma­tion) from nor­mal tis­sues. Sim­i­lar to radi­a­tion dose, the amount of con­trast needed to enhance the organs is depen­dent upon patient body size. Small patients will have smaller organs, less blood vol­ume, and be shorter than larger patients. Thus the amount of CT con­trast needed may not be the same for every patient.

Dr. Shu­man: What are the risks involved when a hos­pi­tal or imag­ing cen­ter does NOT take a patient’s weight into account?

Dr. Mit­sumori: The risks for scan­ning with fixed CT para­me­ters are that when com­pared to an aver­age sized patient, the large patient may have scans with noisy CT images that could lead to inter­pre­ta­tion errors, or a non-diagnostic scan in which the scan may need to be repeated or an alter­na­tive imag­ing test per­formed. For the smaller patient, the risk would be that more radi­a­tion is used than what is needed to gen­er­ate ade­quate, diag­nos­tic images.

Sim­i­lar risks occur with CT con­trast admin­is­tra­tion. If a fixed amount of con­trast is used for every scan that is based on an “aver­age” patient size, then large patients may not receive enough con­trast to ade­quately enhance the inter­nal organs ren­der­ing the scan poten­tially non-diagnostic, and the small patients are given more than the amount of con­trast needed to obtain an ade­quate scan.

Dr. Shu­man: When dis­cussing CT exams with their doc­tors, are there ques­tions a patient should ask regard­ing their weight? In other words, what would make an “informed patient” as it relates to weight and CT?

Dr. Mit­sumori: An informed patient would want to ask if their CT scans will be per­formed with “patient tai­lored” or “patient spe­cific” pro­to­cols that use the amount of radi­a­tion and iod­i­nated con­trast that best match the patient’s body size.

Iterative Reconstruction at UW: an Overview

I am often asked what, exactly, iter­a­tive recon­struc­tion is – and why it is so impor­tant. I thought it would be a good idea to dis­cuss what I do and what my work means for the Uni­ver­sity of Wash­ing­ton Med­ical Cen­ter and our patients.

A brief overview of iter­a­tive reconstruction

Iter­a­tive recon­struc­tion to us means poten­tially sig­nif­i­cant radi­a­tion dose reduc­tion to our patients, but the look of the CT image itself needs some get­ting used to. When we first got the option on our scan­ners, we wanted to make sure that our radi­ol­o­gists would be com­fort­able with the images produced.

So, based on our pro­to­cols at the time, we recon­structed them with vary­ing per­cent­ages of iter­a­tive recon­struc­tion and noise indexes, and had our radi­ol­o­gists eval­u­ate the images and decide what they found to be the most sim­i­lar in noise and image qual­ity to our stan­dard at the time.

They used a double-blind method to eval­u­ate the images, and based on what they decided, for noise index and iter­a­tive recon­struc­tion per­cent­age we were able to reduce radi­a­tion dose to our patients by 40–60 percent.

The evo­lu­tion of iter­a­tive recon­struc­tion at UW

We are con­stantly striv­ing for improve­ment in image qual­ity and dose reduc­tion – both of which lead to bet­ter patient care. So we look again at our exist­ing pro­to­cols and eval­u­ate how we can com­bine cer­tain series or opt for higher noise indexes in order to reduce dose. We also intro­duce dif­fer­ent per­cent­ages of the iter­a­tive recon­struc­tion and dis­play these for our radi­ol­o­gists to fur­ther evaluate.

What UW is doing that oth­ers aren’t

Our radi­ol­o­gists are always will­ing to go out of their com­fort zone in order to reduce dose. I say this again because of their will­ing­ness to take the time to look at images that tra­di­tion­ally would not be pleas­ing to their eyes, but may be more than ade­quate for answer­ing the ques­tions that the order­ing physi­cians need.

And, again, a prime exam­ple of that is the dif­fer­ent per­cent­ages of iter­a­tive recon­struc­tions that they’ve seen and con­tinue to look at, in order to prop­erly eval­u­ate the bal­ance of dose vs. image qual­ity – and always striv­ing to improve both.

Why this work is impor­tant for patients

We always put patients first. To do this, we need to make sure that we give the right amount of radi­a­tion dose. With the mod­ern machines we have, it is far too easy to give too much dose to pro­duce the pret­ti­est of images, but easy is not safe. To use these mod­ern machines prop­erly and respon­si­bly takes a lot of extra work to accu­rately and safely fine tune each pro­to­col for each patient’s needs. Our patients deserve all of that extra effort and more.

Adaptive Iterative Reconstruction Article Featured on Image Wisely

What does adap­tive iter­a­tive recon­struc­tion do? How is it used?

These are ques­tions addressed in an arti­cle of mine fea­tured on the Image Wisely web­site. As men­tioned before on this blog, Image Wisely is an excel­lent and very use­ful resource – for both health care providers and patients – that pro­vides infor­ma­tion on low dose pro­to­cols, radi­a­tion risk, and safety in med­ical imaging.

To read the full arti­cle, click here.

ACR Releases Radiation Safety and Medical Imaging PSAs

The Amer­i­can Col­lege of Radi­ol­ogy, in an effort to address ques­tions and con­cerns about radi­a­tion risk, has cre­ated sev­eral pub­lic ser­vice announce­ments that inform view­ers where they can obtain more infor­ma­tion regard­ing radi­a­tion in med­ical imag­ing. These PSAs have been released for nation­wide broadcast.

The adult-focused ver­sion of the announce­ment directs view­ers to the Image Wisely site, while the pedi­atric ver­sion directs view­ers to the Image Gen­tly site. Each site indi­vid­u­ally serves as the pri­mary resource for addi­tional infor­ma­tion on imag­ing and radi­a­tion safety.

The PSAs can be found here.

Thoughts on Radiation Exposure, Risk

A New York Times op-ed about nuclear radi­a­tion expo­sure, called “Unsafe at Any Dose,” got me think­ing about CT scan radi­a­tion expo­sure – and the ongo­ing debate regard­ing CT scan risks.

Many activ­i­ties and endeav­ors in human life have asso­ci­ated risk. Dri­ving a car is risky; peo­ple die. And the more miles you drive, the greater the risk. But that does not mean we don’t use cars. Rather, we min­i­mize risk by dri­ving care­fully, using seat­belts, etc. And we go ahead and drive in order to cap­ture the benefits.

So it is with med­ical radi­a­tion… and nuclear energy. But an impor­tant note: even with Dr. Caldicott’s pes­simistic pre­dic­tions and num­bers, if you look at human deaths asso­ci­ated with kilo­watt hours of elec­tri­cal gen­er­a­tion, coal pow­ered elec­tric­ity is the worst. Oil is next, and nuclear is at the vary bot­tom of the list (i.e., it has his­tor­i­cally caused the fewest deaths).

Makes one stop and think, doesn’t it?

Patient Resource: Radiation Risk Calculator

Here on this blog I often talk about the impor­tance of patient edu­ca­tion and aware­ness, as it relates to CT scans, radi­a­tion dose and can­cer risks. Informed patients are smart patients! To that end, I wanted to share with you an inter­est­ing resource I recently came across: a “radi­a­tion risk cal­cu­la­tor” spon­sored by the Amer­i­can Soci­ety of Radi­o­logic Technologists.

Accord­ing to the site, the pur­pose of this (free) tool is to “cal­cu­late your dose and esti­mate can­cer risk from stud­ies includ­ing CT scans, x-rays, nuclear scans and inter­ven­tional pro­ce­dures.” I think this is good for patients, if com­bined with coun­sel­ing about the mean­ing of the numbers.

I always say: the more info, the bet­ter – as long as it is under­stood appro­pri­ately. Remem­ber too, that a 1 in 2000 risk of caus­ing can­cer means a 1999 in 2000 risk of not caus­ing cancer…

The Thyroid Shield Controversy: Cancer Fears Overblown

Recently, an episode of Dr. Oz that linked the increase in thy­roid can­cer to imag­ing and biopsy pro­ce­dures prompted an increase in requests for thy­roid shields from women under­go­ing mam­mo­grams. The can­cer risk scare appears to be caused by a chain e-mail that was cre­ated by a viewer after the episode aired. The pub­lic out­cry has reached the point that the Amer­i­can Col­lege of Radi­ol­ogy and the Soci­ety of Breast Imag­ing have issued a joint state­ment to try to over­come fears of high radi­a­tion risk from mammography.

Here in our own offices, we have women show­ing up for mam­mo­grams bring­ing their own thy­roid shields. This is silly – the amount of scat­ter radi­a­tion is so small as to be hardly mea­sur­able with very sen­si­tive instruments.

If you take a thy­roid shield to a mam­mo­gram, to be log­i­cally con­sis­tent, you should be wear­ing it all the time – on any air­plane flight, when sun­bathing… the list goes on!

Study by Dr. Kanal, UW Researchers Featured in JACR

Recent find­ings from blog con­trib­u­tor Dr. Kalpana Kanal and her team of Uni­ver­sity of Wash­ing­ton researchers have been pub­lished in the April issue of the Jour­nal of the Amer­i­can Col­lege of Radi­ol­ogy!

The pur­pose of the study was to exam­ine the vari­a­tion in pedi­atric trauma head CT imag­ing pro­to­cols in Wash­ing­ton State – includ­ing the use (or not) of low radi­a­tion dose CT. Based on their find­ings, the team is now work­ing on a cam­paign to adopt CT dose reduc­tion pro­to­cols through­out the state. For more infor­ma­tion on the study, click here.

Great work by Kalpana and her team!

CT Radiation Overexposure Still a Problem, Regulation Issues are Complex

Unfor­tu­nately, ct scan radi­a­tion over­ex­po­sure con­tin­ues to be a prob­lem in hos­pi­tals and imag­ing facil­i­ties across the coun­try. How­ever, the ques­tion of reg­u­la­tion of dose from ct scan­ners is a com­plex issue. Many say that the best path­way to reg­u­la­tion is through the exist­ing Amer­i­can Col­lege of Radi­ol­ogy mech­a­nisms – such as cer­ti­fi­ca­tion of CT sites and sub­spe­cialty cer­ti­fi­ca­tion of both radi­ol­o­gists and CT tech­nol­o­gists. This may expand to include require­ments for reg­u­lar mon­i­tor­ing of dose from typ­i­cal exams and report­ing the results of such mon­i­tor­ing to a cen­tral ACR registry.

Oth­ers advo­cate a role for the FDA, though that gov­ern­ment agency may turn to a group of experts, such as the ACR or the Soci­ety of Com­puted Body Tomog­ra­phy. A national reg­istry of indi­vid­ual patients which records dose from each CT exam for each patient, and cumu­la­tive dose for each patient, would also be a best prac­tice – Europe does this now in the EU.

Finally, we need many and repeated courses, texts, elec­tronic edu­ca­tional media, and mono­graphs focused on the topic of how to con­sis­tently achieve CT scans at much lower dose than a few years ago. This edu­ca­tion should be widely avail­able and ongoing.

Our recent UW Sym­po­sium on Low Dose CT was a repeat from six months ago, and was equally well attended.

Interview: Recent Discovery of Radiation in Milk Not Cause for Concern

Check out this KING 5 news story where I dis­cuss the recent dis­cov­ery of trace radi­a­tion in milk being sold in Wash­ing­ton, due to the Japan­ese nuclear power plant leaks. As I men­tion in the inter­view, there’s no cause for con­cern, given the amount of radi­a­tion being detected. It’s a tiny frac­tion of the dose you’d be exposed to dur­ing a CT scan, for example.

Watch (and read) the inter­view here.

Virtual Colonoscopy on the Rise

A new study pub­lished in the March issue of the Jour­nal of the Amer­i­can Col­lege of Radi­ol­ogy shows that the use of vir­tual colono­scopies at U.S. hos­pi­tals is increas­ing – even though the pro­ce­dure is not cov­ered by Medicare.

A neat feat of vir­tual colonoscopy is how the radi­a­tion dose asso­ci­ated with the exam has dropped con­sid­er­ably since it was intro­duced. Newer recon­struc­tion tech­niques on newer CT scan­ners have made this possible.

While it is still true that Medicare will not pay for any type of screen­ing (except mam­mog­ra­phy), some com­mer­cial insur­ance com­pa­nies have real­ized the value of screen­ing for colon can­cer, par­tic­u­larly in high-risk patients. Screen CT colonog­ra­phy does well when com­pared to other tests for detect­ing colon tumors and polyps. And patient accep­tance is higher because it is quick and less uncomfortable.

Second Low Dose CT Symposium Was a Great Success!

I am extremely pleased to report that our sec­ond, back-by-popular demand Low Dose CT Sym­po­sium went very well! It was attended by 140 health­care providers, which was an impres­sive turnout. Talks were excel­lent and very engross­ing. There was a great dis­cus­sion panel for the final half-hour (it actu­ally went on for another half-hour after the meet­ing since there was so much dis­cus­sion com­ing out of the ques­tions!). An audi­ence sur­vey score was 5.4 out of a pos­si­ble 6 for qual­ity and impact on practice.

Were you there? What did you think?

High Dose CT Preferred Method…

…for dead people.

Check out this inter­est­ing story, “Radi­ol­ogy Helps Unwrap Mummy Mys­tery,” about a radi­ol­ogy lab help­ing out a uni­ver­sity museum with some mummy research. They were hop­ing that, through the use of CT scans, they’d learn some valu­able infor­ma­tion about the mummy and the per­son he once was.

What caught my eye was this quote: “Radi­a­tion pro­tec­tion is very impor­tant in liv­ing humans…but this con­cern was com­pletely inap­plic­a­ble to this sit­u­a­tion. So we were able to do two things: we were able to use a much higher radi­a­tion dose and also use much thin­ner slices than we would typ­i­cally use on liv­ing patients to exam­ine them.”

Amus­ing, isn’t it? Dead peo­ple are will­ing to pay the price for images that look too good: high radiation.

Ordering CT scans in the ER: Three Questions

One of the most com­mon com­plaints of patients in the ER is abdom­i­nal pain, and as a recent arti­cle at TIME.com details, diag­no­sis is rarely straight­for­ward. It is impor­tant to under­stand that the ER is dif­fer­ent from other places where health­care is pro­vided. ER physi­cians see a broad spec­trum of dis­ease – from the insignif­i­cant to the life-threatening. There are great time con­straints in the ER, as well, and follow-up care is hard to arrange (and may be unre­li­able) so there is pres­sure for a defin­i­tive diag­no­sis in a sin­gle encounter.

Physi­cians con­sid­er­ing the CT scan to assist with diag­no­sis for abdom­i­nal pain or other ill­ness and injuries should con­sider three questions:

1.  Is CT the right test to do for this patient?

Many ER physi­cians are good at a answer­ing this ques­tion, but it is also help­ful to remem­ber that the best expert on appro­pri­ate use is one phone call away: the radi­ol­o­gist. Hav­ing the patient’s EMR handy is impor­tant, too, in report­ing how many CT scans this patient may have had his­tor­i­cally, since this is a data-point in choos­ing whether or not to do CT. A national reg­istry of indi­vid­ual patient cumu­la­tive radi­a­tion dose is com­ing to the U.S., sim­i­lar to the one that now exists in the EEU, but it is not here yet.

2.  If CT is the right test, what kind of CT?

With con­trast or with­out? Oral con­trast or not? Pos­i­tive oral con­trast or neg­a­tive? One pass or three? Arte­r­ial or por­tal venous phase? Abdomen only or abdomen plus pelvis? Again, the radi­ol­o­gist is a valu­able con­sul­tant for get­ting the most infor­ma­tion about the patient’s con­di­tion at the least radi­a­tion cost.

3.  How can the CT scan be done with the low­est pos­si­ble radi­a­tion dose?

Finally, once the kind of CT exam is decided, how can it be done with the low­est pos­si­ble radi­a­tion dose with­out com­pro­mis­ing the diag­nos­tic value of the scan. A well-informed radi­ol­o­gist can reduce the radi­a­tion dose per scan by up to 60 per­cent. For exam­ple, CT of the uri­nary tract with con­trast now can be achieved in a sin­gle pass. Care­ful atten­tion to CT imag­ing para­me­ters can rad­i­cally lower dose (low kVp, mod­u­lated mA, etc.). Lim­it­ing the length of the scan on the patient and care­ful cen­ter­ing of the patient by the tech can greatly reduce dose. In addi­tion, newer scan­ners com­bine bet­ter detec­tors with more com­plex recon­struc­tion algo­rithms to sub­stan­tially lower dose and CT scan radi­a­tion risks.

Upcoming Speaking Engagements

Just wanted to let you know about a cou­ple of upcom­ing events…

First, I’ll be speak­ing at Over­lake Hos­pi­tal in Belle­vue, WA, at the quar­terly Meet­ing of the Asso­ci­a­tion of Hos­pi­tal Radi­ol­ogy Admin­is­tra­tors on Low Dose CT. This is tak­ing place on Feb­ru­ary 23, 2011, at 5:30 p.m.

Com­ing up in early March, I will be Vis­it­ing Pro­fes­sor at the Uni­ver­sity of Cal­i­for­nia, San Diego. On Tues­day, March 1st, I’ll be attend­ing Grand Rounds at 7:30 a.m., and speak­ing at the San Diego Radi­ol­ogy Soci­ety at 7:00 p.m.

Back By Popular Demand: Low Dose CT Symposium Set for March 12, 2011

The Low Dose CT Sym­po­sium is a repeat ses­sion of the Octo­ber 10, 2010 sym­po­sium which drew close to 150 peo­ple and was greatly received! It will be an excel­lent oppor­tu­nity to gain under­stand­ing of the cur­rent think­ing about how to lower dose in CT scan­ning with­out com­pro­mis­ing the diag­nos­tic power of CT. Radi­ol­o­gists, physi­cists, and senior tech­nol­o­gists are com­bin­ing their knowl­edge and expe­ri­ence in mul­ti­ple 20-minute talks about Low Dose CT tech­nique, cov­er­ing all aspects of pro­to­cols, tech­nique, and order­ing appro­pri­ate­ness for use of CT.

The half-day sym­po­sium is tak­ing place March 12, 2011, in Seat­tle at the Uni­ver­sity of Wash­ing­ton Health Sci­ences’ Turner Audi­to­rium, D-209.  The sym­po­sium is avail­able for a max­i­mum of 3.5 AMA PRA Cat­e­gory 1 Cred­its™. Reg­is­tra­tion is required to attend.

For more infor­ma­tion on the event — and to reg­is­ter — please visit www.lowdosecteducation.com.

Here’s a guick look at the agenda:

8:00–8:30am Refresh­ments
8:30am Wel­come William Shu­man, MDFACR
8:40am Why the Unex­am­ined CT Can Be Very High Dose Kalpana Kanal, PhD
9:00am Low Dose CT Technique William Shu­man, MDFACR
9:20am Low Dose CT in the Abdomen: Prac­ti­cal Applications Car­los Cuevas, MD
9:40am Low Dose Tech­niques for Vas­cu­lar CT Lee Mitus­mori, MD
10:00am-10:20am Break
10:20am Low Dose CT: The Technologist’s Perspective Mario Ramos RT,CT
10:40am Low Dose Car­diac CT — Coro­nary Arter­ies, Whole Chest, and Beyond William Shu­man, MDFACR
11:00am Edu­cat­ing Patients about Radiation Janet Busey, MS
11:20am Low Dose CT in the Acute Care Set­ting Mar­tin Gunn, MD
11:40am The Future of Low Dose CT Paul Kina­han, MD
12:00–12:30pm Ques­tions and Panel Discussion

Hope to see you there!

Face Time with Patients Helps Increase Low Dose Understanding

A recent arti­cle in Health Imag­ing dis­cusses a study that caught my eye. Accord­ing to the study, the arti­cle noted, 80 to 90 per­cent of radi­ol­o­gists remain “invis­i­ble to their patients and approx­i­mately half of the pub­lic is unaware of whether radi­ol­o­gists are physi­cians or tech­ni­cians.” In effect, the “com­modi­ti­za­tion of radi­ol­ogy is becom­ing a press­ing con­cern to many practitioners.”

The authors of this study pro­vide a good solu­tion: “By offer­ing an even higher level of per­son­al­ized ser­vice through direct com­mu­ni­ca­tion, radi­ol­o­gists can dis­pel this view­point by show­ing patients that they cus­tomize imag­ing exam­i­na­tions to fit each patient’s indi­vid­ual health­care needs.”

I find this relates to my own expe­ri­ences as a radi­ol­o­gist and, in a way, to the low dose move­ment. One way to lower the dose of CT is to not do inap­pro­pri­ate CT scans. How do you decide what is inappropriate?

This is where the radi­ol­o­gist (a physi­cian) as a knowl­edge­able advi­sor (who con­sults with other physi­cians about imag­ing) comes in.

Face time with patients can help them under­stand this role. It can also help them under­stand that lower dose in their appro­pri­ate CT exams is pos­si­ble with­out com­pro­mis­ing the diag­nos­tic power of the exam – again, achieved through a knowl­edge­able radi­ol­o­gist design­ing the CT exam and mon­i­tor­ing the con­duct of exe­cut­ing the exam.

Important Studies on CT Scans and Lung Cancer Make Headlines, Generate Debate

In the last few months I’ve read sev­eral sto­ries con­cern­ing research about CT screen­ings for lung can­cer.

In mid-November, there was a story mak­ing the rounds among the major news out­lets about a study that found that CT lung scans can reduce the risk of lung can­cer death among for­mer and cur­rent heavy smok­ers. Dur­ing the excite­ment of this study, a New York Times piece was pub­lished that expressed con­cern that the study’s find­ings could eas­ily be taken out of con­text – and per­haps incite unnec­es­sary fear, as well as drive demand for unnec­es­sary scans.

I’d like to point out the impor­tance of this study: it showed a 20 per­cent reduc­tion in mor­tal­ity in patients at very high-risk who were screened with low dose CT com­pared to patients who were not. Sev­eral things to keep in mind about this study – first, it was a study of patients with 30 or more pack-years of smok­ing his­tory. Sec­ond, the tech­nique was a quick and a low dose CT. And third, the costs of false pos­i­tive find­ings and their workup have not yet been analyzed.

Now, another study is gain­ing trac­tion that pro­vides even more sup­port for the find­ings of the Novem­ber study. While this data sug­gests that screen­ing can lower lung can­cer mor­tal­ity sub­stan­tially in high-risk indi­vid­u­als, what we don’t yet know is the cost of a QUALY – a qual­ity adjusted life-year. Cal­cu­lat­ing that cost involves know­ing how much soci­ety had to expend pay­ing for CT exams and the costs of false-positive results in order to cap­ture a saved life-year in an at-risk per­son. Gen­er­ally, if you can save a QUALY for $50,000 or less, it’s worth doing. If more, it’s a debate.

Just some things I’ve been think­ing about as more and more news agen­cies report on these find­ings. I’m inter­ested in learn­ing what you think – what’s your opin­ion on these stud­ies? Was the New York Times piece cor­rect in its cau­tion­ary tone? Or could these find­ings, in fact, be as rev­o­lu­tion­ary as some reporters (and researchers) want us to believe?

CT Appropriateness Key to Usage, Understanding Risk

A recent study I came across found that patients in emer­gency depart­ments have very high con­fi­dence in CT scans and tech­nol­ogy. Fur­ther­more, it seems as if patients get increas­ingly more con­fi­dent that they’ll get a proper diag­no­sis the more test­ing they have done. But com­pound­ing this is another find­ing of the study: most patients’ under­stand­ing of radi­a­tion expo­sure is poor.

The key to this dis­cus­sion is the con­cept of appro­pri­ate­ness. What that means is the bal­ance between cost, risk, and the chance that a test may pro­vide valu­able infor­ma­tion, which impacts on ther­apy, out­come of the dis­ease process, or peace of mind (which has value, too).

As this study points out, patients have con­fi­dence in CT, but that con­fi­dence does not trans­late directly to appro­pri­ate­ness. Risk of CT radi­a­tion is hotly debated, but that too does not equate with appro­pri­ate­ness by itself. And cost effec­tive­ness is just one com­po­nent of the stew that is appropriateness.

So, given all those lim­i­ta­tions, how do we get there? Answer: use the radi­ol­o­gist – equipped with pow­er­ful sup­port tools – as a con­sul­tant to find the bal­ance that opti­mizes appro­pri­ate­ness. The radi­ol­o­gist is an epi­cen­ter of knowl­edge about radi­a­tion risk, cost effec­tive­ness, and the poten­tial pos­i­tive impact of a CT. Add to that sup­port from a deci­sion sup­port pro­gram – which is a com­pi­la­tion of all knowl­edge in these areas – and you have the best path to appro­pri­ate­ness in this com­plex world of high-tech imaging.

Do Patients Understand CT Scan Risks?

An arti­cle that was pub­lished after RSNA talks about a study that found that CT scan radi­a­tion risk in patients may be overblown. How­ever, at the close of the arti­cle, it says that longer-term, more in-depth study is needed. Until then, physi­cians and patients still need to weigh the risks and ben­e­fits of CT.

For patients to both be informed and to under­stand (com­pre­hend) risk related to radi­a­tion is very chal­leng­ing. This is because there are few com­pa­ra­bles in nor­mal daily life which can clearly quan­tify extremely small risks. The one I like the most is: 10 mSv give you a risk of dying from an induced can­cer of about 1 in 4000. Dri­ving a car in the USA for 80,000 miles over 3 years also gives you a risk of about 1 in 4000 of dying in a car accident.

Now, both a CT scan with 10 mSv and 80,000 miles of use of a car bring cer­tain ben­e­fits. But they carry a risk of dying of 1 in 4000. What do you think of that risk/benefit ratio? Would that ratio make you stop dri­ving a car?

Year’s Biggest Advancement in CT Technology?

I recently came across this video from RSNA. About halfway in, they ask the ques­tion, “What is the biggest advance­ment in CT tech­nol­ogy this year?”

I would agree with Dr. Siegel that iter­a­tive recon­struc­tion has stim­u­lated think­ing and con­ver­sa­tion among radi­ol­o­gists about how to sub­stan­tially lower CT dose with­out com­pro­mis­ing the ben­e­fits of CT. Based on our 18 months of expe­ri­ence, we know the reduc­tion is at least 40 per­cent with the cur­rent ver­sion of iter­a­tive recon­struc­tion. And we sus­pect much greater reduc­tions are com­ing. Some of the issues cen­ters around radi­ol­o­gists’ “pref­er­ences” for how a CT images looks. But pref­er­ences can change, even dra­mat­i­cally, when dri­ven by the hope of much lower patient dose.

What do you think – what do you view as the biggest advance­ment in CT?

Obligation to Patients: Minimize Risk and Maximize Benefit

One of the most excit­ing – and talked about – ses­sions at RSNA was called “Radi­a­tion Dose: Can It Be Too Low?” The expert panel had a healthy debate on radi­a­tion dose and risk, and finally reached an agree­ment that CT scans should be lim­ited to “jus­ti­fied and opti­mized stud­ies.” (HealthImaging.com has a good recap of the panel’s discussion.)

The debate about risk can go on, but when prac­tic­ing med­i­cine (radi­ol­ogy) with real patients, the oblig­a­tion is to both min­i­mize risk AND max­i­mize benefit.

So the chal­lenge for radi­ol­o­gists is to lower dose as much as pos­si­ble with­out com­pro­mis­ing the amaz­ing diag­nos­tic power of CT. How to accom­plish this is both sci­ence and art. But we have dis­cov­ered at UW that with a com­bi­na­tion of low dose tech­nique and low dose CT tech­nol­ogy, you can take out up to 40 per­cent of the radi­a­tion dose to the patient (com­pared to 3 years ago) with­out hav­ing any neg­a­tive impact on diag­no­sis. So that num­ber cer­tainly is achiev­able at most sites.

Could we go even fur­ther in dose reduction?

Stay tuned…

CT Exams in Medical Records Becoming Realistic Goal

A new method of extract­ing and archiv­ing patient CT dose infor­ma­tion has been devel­oped, accord­ing to a recent arti­cle in Sci­ence Daily. Called RADIANCE, this new sys­tem should help with com­pli­ance with the Amer­i­can Col­lege of Radiology’s report­ing guide­lines and build greater aware­ness of radi­a­tion dose to patients.

Tessa S. Cook, M.D., lead author of the study that lead to RADIANCE, says that extracted radi­a­tion dose infor­ma­tion “can be used to per­form a vari­ety of analy­ses aimed at qual­ity assur­ance and patient safety. The auto­mated extrac­tion ‘pipeline’ for radi­a­tion dose infor­ma­tion allows us to be more cog­nizant of radi­a­tion dose to our patients, thus result­ing in improved patient care and management.”

It is clear that we are headed toward the record­ing of radi­a­tion dose from each CT scan in the patient’s med­ical record. Ini­tially, this will be in the PACS archive, then in the radi­ol­ogy infor­ma­tion sys­tem (RIS) on the way to being in each radi­ol­ogy CT report. Even­tu­ally, the dose will reside in each patient’s elec­tronic med­ical record (EMR) and a cumu­la­tive record as well – just as they do in Europe today in the EEU.

RADIANCE is a big step in that direction.

Team Effort Needed in Push for Low Radiation Dose CT

In the days that fol­lowed last month’s Low Dose CT Sym­po­sium, I had time to reflect on how won­der­ful it was that the event drew an unprece­dented num­ber of atten­dees. The inter­est in the sym­po­sium was evi­dent by how far some atten­dees trav­eled to get there. I was also struck by the seg­ments of the indus­try that were rep­re­sented in the audi­ence: tech­nol­o­gists, radi­ol­o­gists, tech­ni­cians and admin­is­tra­tors were all there. It made me think about each segment’s rela­tion­ship to one another, and their abil­ity to impact change in the industry.

When dri­ving toward much lower radi­a­tion dose in CT, it’s good to remem­ber that a team effort is needed. Tech­nol­o­gists must be edu­cated on all the tricks and skills needed and must fully under­stand why dose reduc­tion is impor­tant. They can help radi­ol­o­gists be more con­scious of dose exactly when radi­ol­o­gists are urg­ing tech­nol­o­gists to pay close atten­tion. Both techs and radi­ol­o­gists can use their knowl­edge to help edu­cate admin­is­tra­tors about the impor­tance of invest­ing in low dose CT. Every­one can help edu­cate refer­ring clin­i­cians about think­ing of dose when they order, both for an indi­vid­ual study and cumu­la­tive dose (over time) in indi­vid­ual patients. And it is the whole chain of providers who mon­i­tor appro­pri­ate­ness of stud­ies at each and every level.

Educating Patients About Radiation Risk Not Always Easy

Lots of arti­cles are pub­lished on a reg­u­lar basis that talk about pub­lic aware­ness (or lack thereof) of CT scan risks and ben­e­fits. This one’s a recent exam­ple. But here’s the thing, which I’ve dis­cov­ered through per­sonal expe­ri­ence: edu­cat­ing patients about radi­a­tion risk is very chal­leng­ing. This is because extremely low rates of risk are hard to com­pre­hend. It can be talked about in terms of back­ground nat­ural radi­a­tion, or risk of dri­ving a car, for exam­ple. While it is impor­tant that patients be informed, it is also impor­tant that they not be scared away from a test that stands a good chance of help­ing them – a lot. This is a fine balance.

Prac­tic­ing med­i­cine in an emer­gency room envi­ron­ment is dif­fer­ent from in a clinic or a hos­pi­tal. The dis­eases are dif­fer­ent as is the acu­ity. What may not be appro­pri­ate in a fam­ily med­i­cine clinic pop­u­la­tion may be appro­pri­ate in an acutely ill ER patient.

This is why spe­cial­ists in radi­ol­ogy and emer­gency med­i­cine are con­tin­u­ally review­ing appro­pri­ate­ness cri­te­ria, like those pub­lished by the Amer­i­can Col­lege of Radi­ol­ogy.

Patients Want To Know About Radiation Risks

A new study pub­lished in the Novem­ber issue of the Amer­i­can Jour­nal of Roentgenol­ogy con­cluded that patients from the emer­gency depart­ment are more con­cerned about hav­ing their con­di­tion diag­nosed with CT than about the risk of future can­cer from radi­a­tion expo­sure.

Although the patients in this study did not esti­mate the risk of devel­op­ment of can­cer as high, the major­ity of patients wanted some­one to dis­cuss the risk and ben­e­fits of test­ing them. This is not as sim­ple as it sounds. How do we best edu­cate patients about radi­a­tion? Who is respon­si­ble for edu­cat­ing patients about risks and ben­e­fits of radi­a­tion expo­sure from CT – the order­ing provider, the radi­ol­o­gist, or the CT technologist?

Right now it seems that nobody is doing such edu­ca­tion likely due to time con­straints and the fact that it is a dif­fi­cult topic to dis­cuss.  There is no stan­dard­ized way to dis­cuss radi­a­tion with patients and research shows that many physi­cians don’t fully under­stand radi­a­tion, radi­a­tion doses from com­mon tests or pos­si­ble risks from expo­sure to radi­a­tion from med­ical imag­ing. This is a topic that is not going away. We know what our patients want and need, it’s up to us as their health­care providers to deliver.

Communication Networks Help Avoid Repeat CT Scans

Aunt Min­nie recently reported on a study that found that when emer­gency room per­son­nel are knowl­edge­able about pro­to­cols for trans­fer­ring and accept­ing DICOM CDs – which con­tain images of emer­gency CT scans of injured chil­dren – there is a decrease in the num­ber of repeat (unnec­es­sary) exams performed.

How­ever, the authors of the study said that prob­lems arise when CDs aren’t trans­ferred to the appro­pri­ate per­son­nel, lead­ing to unnec­es­sary exams (and unnec­es­sary radi­a­tion expo­sure) even when a CD exists, accord­ing to the article.

Another approach – one which we fol­low – is to set up pre-existing VPN com­mu­ni­ca­tion net­works so stud­ies can be directly down­loaded (quickly), with­out the need for CDs. These often arrive before the trans­fer of the patient. They are set up with the sites that refer more than 5 patients per year. Here we have about 200 such con­nec­tions to other health­care facil­i­ties, which is great for all med­ical records as well as the images from radiology.

It’s National Radiologic Technology Week!

To rec­og­nize National Radi­o­logic Tech­nol­ogy Week, I asked respected CT tech­nol­o­gist (and our CT super­vi­sor) Mario Ramos to share his per­spec­tive on the ben­e­fits of low radi­a­tion dose CT. – Dr. Shuman

Proper dose reduc­tion is not just about hav­ing the right equip­ment. It is essen­tial that every­one is involved, and that they all work as a cohe­sive team in the name of patient safety.

Man­age­ment sup­ports us by mak­ing sure that the right machines, main­te­nance con­tracts and peo­ple are in place. Our radi­ol­o­gists ulti­mately deter­mine the level of noise we allow in images, and that dic­tates the steps we take to reduce dose. As tech­nol­o­gists, we have to have the right work­flow in place to make sure that all those steps for dose reduc­tion are done, such as adjust­ing kV, ma, noise index, and proper shield­ing. Our sup­port staff assists with the busy work that can take away from the focus on the scan at hand, and the physics teams keep our QA/QC pro­to­cols in check. We are very for­tu­nate here at the Uni­ver­sity of Wash­ing­ton to have all these things in place and know that as equip­ment and scan­ning tech­niques con­tinue to evolve, we are able to ensure the high­est level of image qual­ity while main­tain­ing proper dose reduc­tion practices.

Upcoming CT Speaking Engagements

I’ve got two events com­ing up I’d like to share…

The first, on Novem­ber 4, is the Grand Rounds con­fer­ence at Over­lake Hos­pi­tal. The con­fer­ence will focus on radi­a­tion expo­sure and its poten­tial risks with regard to patients receiv­ing mul­ti­ple imag­ing studies/multiple radi­a­tion doses. Should be interesting!

The sec­ond, on Novem­ber 6, is the Wash­ing­ton State Radi­o­log­i­cal Soci­ety (WSRS) annual meet­ing. It’s at the World Trade Cen­ter in Seat­tle, and it’s sched­uled for 4:00 p.m. Click here for more infor­ma­tion about this meet­ing. If you’d like to attend, you can find the reg­is­tra­tion form avail­able for down­load here.

November’s off to a busy start!

CT Scans CAN Be Cost Effective (and Save Lives) in Emergency Situations

A recent study found that the use of CT scan­ners and other advanced imag­ing machines in U.S. hos­pi­tal emer­gency depart­ments “tripled between 1998 and 2007, result­ing in higher costs and longer emer­gency room stays,” accord­ing to an arti­cle by blog­ger Julie Steenhuysen.

Lead researcher Dr. Fred­er­ick Kor­ley of Johns Hop­kins Med­i­cine in Bal­ti­more said his team noticed “a really sig­nif­i­cant increase [in usage] with­out a cor­re­spond­ing increase in the diag­no­sis of life-threatening ill­ness.” He said this sug­gest that there is a “poten­tial amount of overuse or use that is not directly yield­ing any mean­ing­ful clin­i­cal results.”

Actu­ally, the use of all CT and MR from any source more than dou­bled dur­ing that time period.

Emer­gency rooms are under great pres­sure to diag­nose or rule out seri­ous con­di­tions quickly, since every ER in the coun­try is swamped with patients – many of whom can­not get to other forms of care. What is inap­pro­pri­ate in some set­tings may be appro­pri­ate in the ER setting.

In our study of patients with low-risk chest pain who had a car­diac CT early in their ER visit, patients were dis­charged 20 hours faster and with a 40 per­cent cost reduc­tion com­pared to sim­i­lar patients who had a workup with­out car­diac CT.

So it really depends on the indi­ca­tion.

Radiation Bill Signed Into Law

A new piece of leg­is­la­tion was announced recently that radi­ol­o­gists all over the coun­try are talk­ing about: Cal­i­for­nia Gov­er­nor Arnold Schwarzeneg­ger has signed a med­ical radi­a­tion bill into law. It’s the first state law in the United States aimed at “pro­tect­ing patients from exces­sive radi­a­tion expo­sure received dur­ing CT scans and radi­a­tion ther­apy pro­ce­dures,” as reported by Aunt Min­nie.

Accord­ing to the same arti­cle, the bill “requires that radi­a­tion dose be recorded on the scanned image and in a patient’s health records, and that radi­a­tion over­doses be reported to patients, treat­ing physi­cians, and the state Depart­ment of Pub­lic Health (DPH).”

Both the goals of this law are very com­mend­able and worth­while. Putting the dose of each exam into the med­ical record is done in Europe now and should begin in the U.S. This will require some com­mit­ment from radi­a­tion device man­u­fac­tur­ers and from the DICOM stan­dard, but is quite doable.

And dis­clos­ing errors, of any type in any part of health­care, is just part of good practice.

Study Published in American Journal of Roentgenology

The Octo­ber issue of the Amer­i­can Jour­nal of Roentgenol­ogy has just been released, and it fea­tures a recent study I con­ducted with blog con­trib­u­tor Janet Busey and col­leagues Kel­ley Branch, Lee Mit­sumori, Jared Strote, Dou­glas Green and James Caldwell.

The study, “Neg­a­tive ECG-Gated Car­diac CT in Patients with Low-to-Moderate Risk Chest Pain in the Emer­gency Depart­ment: 1-Year Follow-Up,” shows that for patients with low-to-moderate risk chest pain eval­u­ated in the emer­gency depart­ment, adverse car­diac events may be rare dur­ing the year after a neg­a­tive car­diac CTA scan.

To read the study, click here (a sub­scrip­tion is needed to read the full arti­cle, though you can view the abstract for free).

ACR Guidelines Still Best Resource for Determining Appropriateness of CT Imaging

William R. Hendee, Med­ical Col­lege of Wis­con­sin, makes some very valid points in a recent arti­cle about overuse of CT scans and the harm­ful effects unnec­es­sary exams have on both patients and the health­care indus­try. Specif­i­cally, he says that radi­ol­o­gists can “play a big role in edu­cat­ing order­ing physi­cians about what scans are appro­pri­ate and when.”

A big part of the train­ing and experience-based learn­ing of radi­ol­o­gists is what imag­ing tests are appro­pri­ate for spe­cific health­care prob­lems and what imag­ing tests are inap­pro­pri­ate. Inap­pro­pri­ate means the imag­ing test has lit­tle chance of adding sig­nif­i­cant value to the diag­no­sis and ther­apy of the patient, espe­cially rel­a­tive to its cost.

The Amer­i­can Col­lege of Radi­ol­ogy (ACR) has spent more than a decade devel­op­ing imag­ing appro­pri­ate­ness guide­lines for hun­dreds of clin­i­cal prob­lems and indi­ca­tions. These ACR appro­pri­ate­ness guide­lines are based on the best avail­able sci­en­tific evi­dence and were writ­ten by pan­els of best sub-specialized experts. The guide­lines each get revised every three to five years as new evi­dence becomes avail­able. There is no bet­ter source avail­able for appro­pri­ate­ness of diag­nos­tic imaging.

The deci­sion sup­port com­puter pro­grams men­tioned in the arti­cle start with the ACR appro­pri­ate­ness guide­lines and cre­ate a quick way for refer­ring physi­cians to know if any imag­ing test they order is appro­pri­ate. At the point of com­put­er­ized imag­ing exam order entry into an elec­tronic sys­tem, the deci­sion sup­port exam­ines the entered indi­ca­tions for an imag­ing exam and then either agrees with doing the exam, or cau­tions that the exam may be only mar­gin­ally indi­cated – or states that by gen­er­ally accepted cri­te­ria the requested exam is unindi­cated. There is edu­ca­tion involved, as the evidence-based rea­sons an exam is unindi­cated are pro­vided to the order­ing physi­cian, along with sug­ges­tions for a bet­ter approach to the patient’s prob­lem (often involv­ing some other type of imag­ing). These deci­sion sup­port pro­grams are now run­ning in sev­eral health­care enter­prises, and they hold good hope for decreas­ing inap­pro­pri­ate com­plex imag­ing exam uti­liza­tion with­out block­ing access to appro­pri­ate tests.

Low Dose CT Symposium Set for October 2

The Low Dose CT Sym­po­sium will be an excel­lent oppor­tu­nity to gain under­stand­ing of the cur­rent think­ing about how to lower dose in CT scan­ning with­out com­pro­mis­ing the diag­nos­tic power of CT. Radi­ol­o­gists, physi­cists, and senior tech­nol­o­gists are com­bin­ing their knowl­edge and expe­ri­ence in mul­ti­ple 20-minute talks about Low Dose CT tech­nique, cov­er­ing all aspects of pro­to­cols, tech­nique, and order­ing appro­pri­ate­ness for use of CT.

The half-day sym­po­sium is tak­ing place Octo­ber 2, 2010, in Seat­tle at the Uni­ver­sity of Wash­ing­ton Health Sci­ences’ Turner Audi­to­rium, D-209. Reg­is­tra­tion is required to attend. Atten­dance is free, but a $25/50 charge applies to those atten­dees request­ing CME credit.

For more infor­ma­tion on the event, please visit www.lowdosecteducation.com. Or to go directly to the reg­is­tra­tion page, please click here.

Note for atten­dees: We’ve already been approved for 3.5 AMA CME Cat­e­gory 1 cred­its for the activ­ity; ASRT cred­its pending.

Here’s a guick look at the agenda:

8:00–8:30am Refresh­ments
8:30am Wel­come William Shu­man, MDFACR
8:40am Why the Unex­am­ined CT Can Be Very High Dose Kalpana Kanal, PhD
9:00am Low Dose CT Technique William Shu­man, MDFACR
9:20am Low Dose CT in the Abdomen: Prac­ti­cal Applications Car­los Cuevas, MD
9:40am Low Dose Tech­niques for Vas­cu­lar CT Lee Mitus­mori, MD
10:00am-10:20am Break
10:20am Low Dose CT: The Technologist’s Perspective Mario Ramos RT,CT
10:40am Low Dose Car­diac CT — Coro­nary Arter­ies, Whole Chest, and Beyond Kel­ley Branch, MD
11:00am Edu­cat­ing Patients about Radiation Janet Busey, MS
11:20am Low Dose CT in the Acute Care Set­ting Mar­tin Gunn, MD
11:40am The Future of Low Dose CT Paul Kina­han, MD
12:00–12:30pm Ques­tions and Panel Discussion

Hope to see you there!

CT Perfusion Dose – What is all the Hue and Cry About?

Last year a New York Times inves­ti­ga­tion uncov­ered more than 200 radi­a­tion over­dose cases at Cedars-Sinai Med­ical Cen­ter. Accord­ing to a New York Times follow-up pub­lished on July 31 this year, 200 addi­tional cases were revealed at other hos­pi­tals lead­ing to more than 400 cases nation­wide. The radi­a­tion over­dose deliv­ered to patients in these over­dose cases was between 4 to 13 times higher than a typ­i­cal dose for the per­formed scans. These over­doses led patients to expe­ri­ence hair loss, headaches, con­fu­sion, and may increase their long-term risk of can­cer and pos­si­ble eye and brain dam­age. The patients had received CT brain per­fu­sion exams, which help to iden­tify strokes through a num­ber of blood flow images.

Why did these over­doses hap­pen?  This could be due to equip­ment mal­func­tion, the need for “pret­tier” clin­i­cal images (requir­ing high radi­a­tion dose), or a seri­ous lack of oper­a­tor knowl­edge in set­ting up the CT imag­ing pro­to­cols for this type of exam. CT brain per­fu­sion is a high-dose exam but can be per­formed safely if the tech­nol­o­gists, physi­cists and radi­ol­o­gists work dili­gently together to ensure that the CT imag­ing pro­to­cols are set up opti­mally to fol­low the As Low As Rea­son­ably Achiev­able (ALARA) prin­ci­ple. The dose deliv­ered by this exam should also be mon­i­tored on a reg­u­lar basis to ensure it remains at min­i­mal lev­els and no equip­ment mal­func­tion or dose creep has occurred.  Physi­cians should also be aware of the poten­tial side effects, as dis­cussed above, which can be trig­gered by such high-dose exams.

Fol­low­ing 2009’s over­dose dis­cov­er­ies, the FDA launched a col­lab­o­ra­tive Ini­tia­tive to Reduce Unnec­es­sary Radi­a­tion Expo­sure from Med­ical Imag­ing, to pro­mote the safe use of med­ical imag­ing devices, sup­port informed clin­i­cal deci­sion mak­ing, increase patient aware­ness, and opti­mize patient expo­sure to radiation.

At the recent Amer­i­can Asso­ci­a­tion of Physi­cists in Med­i­cine (AAPM) annual meet­ing, the patient safety sym­po­sium focused on these over­dose cases and the AAPM CT dose summit’s recent efforts to ensure CT scan para­me­ter opti­miza­tion and patient safety.  The AAPM also pro­duces reports on qual­ity and safety in med­ical imag­ing and radio­ther­apy, along with letter-writing and pol­icy cam­paigns tar­geted at the gov­ern­ment and public.

Researchers at Mayo Clinic are also inves­ti­gat­ing the use of new image-processing algo­rithms to reduce the dose for CT per­fu­sion exams up to 95 per­cent and main­tain the same image qual­ity as a high-dose per­fu­sion exam.

If appro­pri­ate steps are taken to ensure patient safety and dose opti­miza­tion, the ben­e­fits from a CT brain per­fu­sion scan far out­weigh the risks asso­ci­ated with it.

Is Government Regulation Necessary for CT?

A recent edi­to­r­ial in the Jour­nal of the Amer­i­can Med­ical Asso­ci­a­tion took the posi­tion that the best course of action to address the issues of CT overuti­liza­tion, qual­ity con­trol and train­ing would be gov­ern­ment reg­u­la­tion, accord­ing to an arti­cle on Health­Imag­ing.

In the orig­i­nal edi­to­r­ial, authors David J. Bren­ner, PhD and Hed­vig Hri­cak, MD reported that “the radi­a­tion dose in Amer­ica has dou­bled over the past 30 years, and med­ical imag­ing con­tributes half of the dose to the U.S. pop­u­la­tion,” as stated in Health­Imag­ing. They argue that only through national leg­is­la­tion will we be able to ensure lower CT radi­a­tion dose and an improve­ment in over­all safety to patients under­go­ing CT exams.

Actu­ally, there are very good resources avail­able now for decid­ing appro­pri­ate­ness and sup­port­ing refer­ring physi­cians, such as the Amer­i­can Col­lege of Radiology’s (ACR) appro­pri­ate­ness cri­te­ria or com­mer­cially avail­able, evidenced-based deci­sion sup­port pro­grams which are built into elec­tronic order entry systems.

Rather than have the FDA develop a new agency, per­haps wider and bet­ter appli­ca­tion of these exist­ing resources and reg­u­la­tion through soci­eties of experts (like the ACR and the Radi­o­log­i­cal Soci­ety of North Amer­ica) might be impactful.

Debating the Cumulative Radiation Dose Theory

Despite the atten­tion being given to the cumu­la­tive CT scan radi­a­tion effect and the buzz sur­round­ing risks of repeat CT scans, one lead­ing expert is dis­put­ing the theory.

As reported in Diag­nos­tic Imag­ing, Richard Morin, Ph.D, chair of the Amer­i­can Col­lege of Radiology’s safety com­mit­tee says, “There is no radi­a­tion biol­ogy to demon­strate CTs are addi­tive in any way.”

Morin uses a dri­ving anal­ogy that relates prob­a­bil­ity of an acci­dent to the num­ber of miles logged by a dri­ver, but notes that there is not a cer­tain mile thresh­old, like 200 miles, that would trig­ger an accident.

I like the dri­ving anal­ogy and used it in my recent post Mea­sur­ing Risk: Dri­ving vs. CT. Dri­ving is some­thing that most of us can relate to, and there­fore the num­bers are more mean­ing­ful, so I’ve tried to quan­tify it even further.

Here’s how I like to look at the risk: The risk of dying from a can­cer induced from a CT of the abdomen and pelvis in a mid­dle aged male is sim­i­lar to the risk of dying in a car acci­dent if you drive 36,000 miles — both are about one in 2000.

The debates over cumu­la­tive dose the­ory will con­tinue, and so I feel it’s impor­tant to explain the risks in ways peo­ple can under­stand – so that they don’t turn down any life-saving exams out of fear or misunderstandings.

While Dr. Morin explains that there is no way to fig­ure out whether a per­son devel­oped can­cer due to radi­a­tion, a car­cino­gen or chance, he does say “it’s impor­tant that the right test is ordered at the right time.”  I’ll add that it’s always a good idea to look at low­er­ing the CT dose, too.

And while the effect of cumu­la­tive dose from mul­ti­ple exams is unproven, we really must take the most con­ser­v­a­tive posi­tion when it comes to pub­lic health and assume the effect is cumulative.

Low Dose CT for Cardiac Imaging

Find­ings of a recent population-based study fea­tured in the Jour­nal of Amer­i­can Col­lege of Car­di­ol­ogy (JAAC) sug­gest car­diac imag­ing may be putting younger adults at risk due to radi­a­tion exposure.

The study demon­strated that there are siz­able rates of radi­a­tion expo­sure for patients 35–54 years, many of whom will likely live long enough for such long-term com­pli­ca­tions (as malig­nancy) to poten­tially develop,” wrote Jer­sey Chen, MD.

While the results may make car­di­ol­o­gists give fur­ther thought to the tests they rec­om­mend and alter­na­tives they can use, oth­ers point out that the ben­e­fits of the test must be weighed against the risks of radi­a­tion exposure.

It is very unusual for a patient in this age range to get a car­diac CT scan. But if they do need one, we can now scan them using less than 2 mSv of radi­a­tion (com­pared to 10–25 mSv in 2005).

That means the risk of dying from a can­cer induced by the CT scan (1 in 4,000) is about the same as the risk of dying in a car acci­dent if they were to drive 70,000 miles (about 5 years of dri­ving for the aver­age Amer­i­can) which is also about 1 in 4,000.

Keeping Patients Up To Date

Part of doing research at an aca­d­e­mic insti­tu­tion requires con­sent­ing patients to par­tic­i­pate in research stud­ies involv­ing radi­a­tion expo­sure. I’m always amazed at the num­ber of patients that have no idea that their clin­i­cally ordered pro­ce­dure involves radi­a­tion, because nobody took the time to explain this. Patients read the papers, they watch the news and they are fully aware of the ongo­ing media frenzy sur­round­ing radi­a­tion in med­i­cine. Patients often ask me, “Is it safe?” While the risk/benefit debate about ion­iz­ing radi­a­tion expo­sure con­tin­ues to be a hot topic in the med­ical com­mu­nity, we must not for­get to keep our patients in the loop.

Edu­cat­ing patients that radi­a­tion often is nec­es­sary in med­i­cine can be extremely chal­leng­ing – but it is more crit­i­cal now than it has ever been. Talk­ing to a patient about radi­a­tion expo­sure is much dif­fer­ent than talk­ing to your radi­ol­ogy col­league, espe­cially when the true incre­men­tal risk to patients from med­ical radi­a­tion is still under much debate. There needs to be a coor­di­nated effort at each insti­tu­tion to make sure that patients are receiv­ing cor­rect and accu­rate infor­ma­tion about radi­a­tion. The imag­ing com­mu­nity needs to work together to devise web­sites and read­ing mate­ri­als that edu­cate the pub­lic about radi­a­tion expo­sure and risks ver­sus ben­e­fits of imag­ing with radi­a­tion.  Every­one involved in patient care must under­stand radi­a­tion, radi­a­tion risks, alter­na­tives to scan­ning and what tech­niques are used to keep dose as low as possible.

Resources on explain­ing radi­a­tion to patients:

1. RadiologyInfo.org

2. “How to Explain Radi­a­tion Risk” from the Wash­ing­ton State Depart­ment of Health

3. Wanzhen Zeng’s “Com­mu­ni­cat­ing Radi­a­tion Expo­sure: A Sim­ple Approach

Does Variability in CT Dose from Multi-Detector CT Scanners Matter?

CT radi­a­tion dose has recently been in the lime­light, not only in the news media but also for patients under­go­ing CT exams. Esti­mat­ing CT dose is com­plex and fur­ther chal­lenged by the dif­fer­ent types of CT scan­ners avail­able in the mar­ket today. In a recent study, inves­ti­ga­tors col­lected CT radi­a­tion dose mea­sure­ment data from all the multi-detector CT (MDCT) scan­ners used in the National Lung Screen­ing Trial. Radi­a­tion dose in CT is defined as CT Dose Index (CTDI). CTDI rep­re­sents the aver­age absorbed dose, along the length of the patient’s body from a series of con­tigu­ous scans. Nor­mal­ized CTDI can be used to deter­mine the effi­ciency of the CT scan­ner, and finally the dose imparted to patients. Nor­mal­ized CTDI rep­re­sents the dose per mAs (tube cur­rent x rota­tion time) where the mAs deter­mines the num­ber of x-ray pho­tons uti­lized per rota­tion of the CT scanner.

The results of this study imply that one needs to be aware of the dif­fer­ences in nor­mal­ized CTDI – not only between man­u­fac­tur­ers, but also between mod­els of CT scan­ners from the same man­u­fac­turer (Table 4 of this study).

This study showed that the aver­age nor­mal­ized CTDI var­ied greatly (by a fac­tor of 2) across all scan­ners from dif­fer­ent man­u­fac­tur­ers. The dose effi­ciency of the CT scan­ners improves as the scan­ners get more com­plex, with the num­ber of detec­tors along the length of the patient increas­ing from four or eight to six­teen and beyond (e.g.: 4– 8– or 16– slice CT scan­ner). This has an impact on image qual­ity and patient dose because the more effi­cient the CT scan­ner, the less the dose to the patient to acquire the desired image quality.

The dose data in this study was col­lected for 96 MDCT scan­ners across 33 par­tic­i­pat­ing insti­tu­tions. While the study did not focus on image qual­ity and patient dose, it did exam­ine scanner-specific radi­a­tion dose data across all institutions.

CT Scans and Patient Safety: The Debate for Solutions Rages On

A recent arti­cle address­ing the ongo­ing debate over the safe use of med­ical imag­ing fea­tures the opin­ions of two indus­try experts on how we should be work­ing to lower radi­a­tion doses from CT scans and other imag­ing exams.

On one side of the debate is Dr. Rebecca Smith-Bindman, who believes that it should be the job of the U.S. Food and Drug Admin­is­tra­tion to pro­tect patients by reg­u­lat­ing radi­a­tion from CT scan­ners. “Radi­a­tion doses are higher than they should be and they vary dra­mat­i­cally within and between facil­i­ties and that is not accept­able,” she said in the article.

Dr. Bruce Hill­man, on the other hand, believes that the prob­lem lies with doc­tors who order too many scans (which can lead to find­ing con­di­tions that might have been bet­ter left untreated). And, accord­ing to the arti­cle, he thinks that “heap­ing more reg­u­la­tion on an indus­try that has already been squeezed by Medicare cuts may squelch the kind of inno­va­tion that pro­duced CT scan­ners in the first place.”

In my opin­ion, there are three answers to this storm:

1.  We need to make greater efforts to strive for appro­pri­ate use of CT. For that we can turn to the best author­ity avail­able: the Amer­i­can Col­lege of Radi­ol­ogy Appro­pri­ate­ness Guide­lines. Com­put­er­ized deci­sion sup­port pro­grams in elec­tronic med­ical records can help, too.

2.  We need to strive for much lower radi­a­tion dose per scan. We know that the dose per scan fre­quently can be reduced by up to 60 per­cent by the use of bet­ter CT tech­niques (selec­tion of imag­ing para­me­ters, shield­ing) and by mod­ern CT tech­nol­ogy. Here guide­lines from orga­ni­za­tions like the Soci­ety for Com­puted Body Tomog­ra­phy (SCBT/MR), an arm of the ACR, can be help­ful and can drive edu­ca­tion for all lev­els of health­care providers.

3.  We need to ensure that finan­cial incen­tives lead­ing to con­flict of inter­est are min­i­mized, so that patients can be com­fort­able that any CT scans are done only for appro­pri­ate diag­nos­tic investigation.

Finally, in all the storm about cost and radi­a­tion fear, we need to remem­ber that CT is a very pow­er­ful diag­nos­tic tool that pro­vides defin­i­tive infor­ma­tion which can be used to save lives and select the best ther­apy quickly. It does far more good than harm — in every insti­tu­tion, every day.

Is Treatment Necessary? Ask a Radiologist.

In a recent New York Times arti­cle, Dr. Peter Libby, chief of car­dio­vas­cu­lar med­i­cine at the Brigham and Women’s Hos­pi­tal in Boston, dis­cusses the ben­e­fits ver­sus the risks and costs of med­ical pro­ce­dures like CT scans. In par­tic­u­lar, he addresses the issue of inci­den­talo­mas, which occur when “med­ical scans pick up inci­den­tal find­ings that may be benign, lead­ing to com­pli­ca­tions that make an oth­er­wise healthy per­son ill.”

Dr. Libby writes, “While con­tem­po­rary imag­ing modal­i­ties offer pow­er­ful and much needed tools for diag­no­sis and man­age­ment when appro­pri­ately deployed, we should bear in mind the poten­tial risks they entail if used indiscriminately.”

The prob­lems cre­ated by inci­den­talo­mas is one area where you really need an expert: your radiologist.

This is what radi­ol­o­gists do – they don’t merely detect find­ings on CT scans, but also attach sig­nif­i­cance (or insignif­i­cance) to each finding.

When all your train­ing and all your expe­ri­ence is in CT scans and their find­ings, you become pretty good at telling inci­den­talo­mas from true prob­lems which need more inves­ti­ga­tion. Not per­fect, of course, but pretty darn good.

Measuring Risk: Driving vs. CT

In the past cou­ple weeks there has been much talk about the can­cer risk from med­ical radi­a­tion. Accord­ing to a recent Reuters arti­cle, one chest CT scan deliv­ers the same radi­a­tion (and risk) as 100 chest X-rays. How­ever, these num­bers still do not com­mu­ni­cate the big­ger pic­ture: CT can­cer risk can be more clearly explained.

Since most peo­ple never get close to get­ting 100 chest X-rays, we need to find a more com­mon point of com­par­i­son. Dri­ving, how­ever, is some­thing most North Amer­i­cans do on a reg­u­lar basis, and its risks are well-publicized.

43,000 peo­ple died in 2007 from car acci­dents in the U.S. Dur­ing that same year, U.S. dri­vers drove 3 tril­lion miles, accord­ing to the U.S. Cen­sus Bureau. Based on these sta­tis­tics, the risk of dying from dri­ving 35,000 miles is about 1 in 2000 (0.05%).

An abdominal/pelvic CT scan deliv­ers about 15 mil­liSiev­erts of radi­a­tion. In our cal­cu­la­tions, using the most con­ser­v­a­tive data from the atomic bomb­ings of Hiroshima and Nagasaki and the Cher­nobyl dis­as­ter, the risk of mor­tal­ity from radiation-induced can­cer is also about 1 in 2000 (0.05%).

Pub­lished data also sup­ports this risk level: Bren­ner and Hall have esti­mated that the total life­time attrib­ut­able risk of death from can­cer after receiv­ing an abdom­i­nal CT with 240 mAs, is in the 0.06%-0.07% range (this esti­mate is for ages 15–25; CT risk drops rad­i­cally after age 25).

Thus: If the aver­age U.S. dri­ver trav­els just under 14,000 miles per year… then the risk of dying in car acci­dent (if only dri­ving for 2 years, or 35,000 miles) is about the same as the life­time risk of dying from can­cer induced by the radi­a­tion in a CT of the abdomen and pelvis.

Of course, dri­ving more care­fully and low­er­ing the CT dose per scan both are good ideas.

New Algorithm Provides Lower Radiation Dose, Better Image Quality

At the recent Inter­na­tional Soci­ety for Com­puted Tomog­ra­phy (ISCT) meet­ing in San Fran­cisco, stud­ies were pre­sented show­ing that CT scan­ning with a new algo­rithm, called model-based iter­a­tive recon­struc­tion (MBIR), could offer bet­ter image qual­ity and lower radi­a­tion dose than scan­ning with an adap­tive sta­tis­ti­cal iter­a­tive recon­struc­tion (ASIR).

Accord­ing to AuntMinnie.com, “researchers claim that MBIR out­per­forms pre­vi­ous efforts to max­i­mize the util­ity of low-dose CT exams, with researchers report­ing excel­lent image qual­ity and enhanced lesion conspicuity.”

Uni­ver­sity of Wash­ing­ton is one of the inter­na­tional sites for the multi-center trial of MBIR. My col­league, Paul Kina­han, was one of the two sci­en­tists who reported on MBIR images at the ISCT meeting.

We are very impressed with the tech­nique here – it may some­day result in a fur­ther huge dose reduc­tion for CT. At this point it is in early stages of devel­op­ment and assess­ment of its clin­i­cal impact has not yet begun. But it looks very promising!

Standardization Protocols for CT Would Help Lower Dose, Increase Patient Safety

Last month, the Amer­i­can Asso­ci­a­tion of Physi­cists in Med­i­cine (AAPM) hosted national Dose Sum­mit that focused on the need for stan­dard­iza­tion pro­to­cols for CT scan­ning, which would help to ensure patient safety and lower asso­ci­ated radi­a­tion risks dur­ing CT exams.

Accord­ing to an e! Sci­ence News arti­cle, sum­mit atten­dees included some of the world’s lead­ing experts in CT imag­ing. Orga­nizer Cyn­thia McCol­lough, Ph.D., said the sum­mit “achieved its goal of iden­ti­fy­ing sev­eral issues that need to be dealt with by the med­ical imag­ing com­mu­nity in order to address the safety con­cerns of patients at U.S. hos­pi­tals and clinics.”

This sum­mit also made progress in “devel­op­ing con­sen­sus CT pro­to­cols and mak­ing them freely avail­able via the Inter­net to hos­pi­tals and clin­ics across the United States.” CT pro­to­cols (or “imag­ing para­me­ters”) define how equip­ment is used for cer­tain procedures.

In my opin­ion, stan­dard­iza­tion of pro­to­cols is a pow­er­ful way to lower CT dose. In a recent study pub­lished in the Annals of Inter­nal Med­i­cine, adja­cent hos­pi­tals in the San Fran­cisco Bay area had a 13-fold dif­fer­ence in CT exam radi­a­tion dose for sim­i­lar stud­ies done for sim­i­lar indi­ca­tions. The dif­fer­ence was all in the tech­nique para­me­ter selection.

With stan­dard­ized pro­to­cols, groups of radi­ol­o­gists can get together to study how to do var­i­ous types of CT exams with the low­est dose but yet still pro­duc­ing good diag­nos­tic infor­ma­tion. Once they agree on CT tech­nique para­me­ter selec­tion with low dose as a goal, they can all use the same pro­to­cols and prac­tices. This can dra­mat­i­cally lower the dose to a patient pop­u­la­tion – through stan­dard­iza­tion on best prac­tices in CT.

CT Radiation Risks Outweighed When Preventing, Guiding Acute Appendicitis Surgery

One of the largest stud­ies to date has con­firmed the accu­racy of CT scans for acute appen­dici­tis in adults, which sup­ports the use of CT for diag­nos­tic and sur­gi­cal means when risk for radi­a­tion expo­sure is low, accord­ing to find­ings pub­lished in a recent AuntMinnie.com article.

Dr. Perry Pick­hardt, pro­fes­sor of Radi­ol­ogy at the Uni­ver­sity of Wis­con­sin, said that “at least three other stud­ies con­firmed that the neg­a­tive appen­dec­tomy rate dropped from more than 20 per­cent to less than 10 per­cent with the use of CT… but one thing that was lack­ing was the actual diag­nos­tic per­for­mance or accu­racy with MDCT… so we looked at what I think is the largest CT-based cohort for appendicitis.”

Dr. Pickard pre­sented this data at the Inter­na­tional Soci­ety for Com­puted Tomog­ra­phy (ISCT) meet­ing I just attended in San Francisco.

This is a very good exam­ple of how CT can accu­rately pre­vent surgery when it is not needed while also guid­ing cor­rect surgery when it will do a lot of good. In this appli­ca­tion, CT is cost-effective and does a lot of good – way out­weigh­ing any (very low) risk from the radi­a­tion. For adults it is the diag­nos­tic exam of choice in sit­u­a­tions where signs and symp­toms raise con­cern about pos­si­ble appendicitis.

Low Dose CT Can Make Scanning Safer

Patient receiving a low dose CT scan which reduces radiation risk.It’s a fact of life that all CT scans involve radi­a­tion. And cer­tain types of diag­noses and dis­eases are going to require reg­u­lar repeated CT scans — result­ing in a high cumu­la­tive CT radi­a­tion dose to the patient over time.  But as a recent news story pro­filed, there is a new tech­nique and tech­nol­ogy that can help reduce CT scan radi­a­tion expo­sure by up to 60%.

>watch the news story at King5.com

Researchers at the Uni­ver­sity of Wash­ing­ton have pushed the fron­tiers of CT tech­nique by cir­cum­vent­ing the nois­i­ness and blur­ri­ness of images scanned at very low radi­a­tion dose. These noisy images are made sharp and clear by bet­ter soft­ware recon­struc­tion tech­nol­ogy. It’s a bit like what NASA does with high alti­tude satel­lite tech­nol­ogy. This means that the same diag­nos­tic power is achiev­able with much less radi­a­tion to the patient.

This new approach works for all types of CT scans, but can be espe­cially impor­tant for  chil­dren and cer­tain areas of the body – in par­tic­u­lar, the female breast, the gonads and other tis­sues in the abdomen. These are par­tic­u­larly radi­a­tion sen­si­tive, so we want CT scans to be as low in radi­a­tion dose as pos­si­ble with­out com­pro­mis­ing the diag­nos­tic power of the CT scan. Low dose tech­nique com­bined with low dose tech­nol­ogy accom­plishes this.

New inno­va­tions are con­tin­u­ally being made in the field of med­ical imag­ing. If you need a CT scan, it’s always OK to ask your doc­tor if you can get one with a lower dose of radiation.

Discussing the Benefits of Low Dose CT Scans

Radi­a­tion is part of nature. We’re all exposed to radi­a­tion every day in very small amounts. But the amount of radi­a­tion being used for med­ical diag­no­sis has been increas­ing over the last 20 years or so – to a point where it is now rais­ing new con­cerns about CT scan risks. In fact, the use of CT has increased over the last decade to the point where we’re now doing around 60 mil­lion CT scans a year in the United States.

So what does this mean for patients?

What other options are avail­able to min­i­mize the effects of CT scans?

How can patients go about try­ing to make smart deci­sions about the risks and ben­e­fits of CT scans?

Last Octo­ber, I took part in a Webi­nar for Patient Power with med­ical physi­cist Dr. Kalpana Kanal that addresses these ques­tions and more – touch­ing on radi­a­tion dosage and risk, new tech­nolo­gies, and tech­niques for lim­it­ing exposure.

>watch the webinar

A Study in Cost Effective Care

Find­ings pre­sented by researchers at the Radi­o­log­i­cal Soci­ety of North America’s RSNA 2009 event are shin­ing new light on the impor­tance of under­stand­ing cost effec­tive­ness in CT scan use. In par­tic­u­lar, I had the oppor­tu­nity to design and per­form a study that showed how the high neg­a­tive pre­dic­tive value of ECG-gated car­diac CT in low– to moderate-risk chest painpatients may allow an ear­lier yet safe dis­charge from an emer­gency depart­ment (ED) at a con­sid­er­able cost savings.

For exam­ple, the stan­dard of care for chest pain is an ECG, a blood test and a nuclear stress test – which keep a patient in the ED an esti­mated 30 hours and can cost as much as $8,000. A gated car­diac coro­nary CT angiogram (CCTA) done instead early dur­ing the ER visit could rule out coro­nary artery steno­sis plus other causes of chest pain, result­ing in the safe dis­charge of a patient in just five hours at a cost of about $4,000.

But it’s not just about find­ing ways to lower costs. By avoid­ing the nuclear test and doing a low dose CT, patients also reduce the total radi­a­tion dose – result­ing in a safer over­all procedure.

And this is just one exam­ple of the ben­e­fits that can be found in reex­am­i­nat­ing some of the tra­di­tional approaches to diag­no­sis and med­ical imag­ing.