Annual screening for lung cancer low-dose CT

This is a major advance as American healthcare evolves from reactive to preventive.

But a key to success in this lung cancer screening program is keeping the radiation dose of each exam as low as possible – certainly well below one mSv. Ideally, a low dose approach would involve model based or some other form of iterative reconstruction. All the other techniques to minimize dose should be employed together. Fortunately, this is an application where very low kVp will work well (70-100).

Next – and possibly even more impactful: coverage for screening CT colonography.

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.

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.

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.

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!

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!

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.