A 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.
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.
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!