The radiology world was turned on its head this week with the publication of a new paper in JAMA Internal Medicine on CT radiation risk. Researchers estimated that all the CT scans performed in the U.S. in a single year would cause more than 100k cancers over the lives of the patients who got them.
Radiation risk has always been the Achilles heel of CT, radiology’s workhorse modality for advanced imaging.
- But CT is plagued by dose variation and a lack of reporting on exactly how much dose patients are getting – especially when it exceeds guidelines.
In the new study, researchers led by radiation safety expert Rebecca Smith-Bindman, MD, of UCSF used existing estimates of low-level radiation risk to calculate how many cancers would result from the 93M CT scans performed in the U.S. in 2023, finding …
- CT radiation dose would cause 103k future cancers over the lifetimes of the patients.
- At the current rate, “CT-associated cancer” would account for 5% of all cancers – about the same number caused by alcohol.
- The study’s projection of CT-linked cancers is 3X-4X higher than previous estimates, mostly due to the growth in CT utilization.
The paper generated pushback from sources including the ACR and AAPM, who questioned whether it really reveals any new information about the risks of CT radiation.
- They reiterated the medical value of CT scans, noting that the research was based on statistical models and that there are no published studies directly linking CT scans to cancer.
Another thing the paper doesn’t touch on are the dramatic reductions in CT radiation dose that have occurred in recent years.
- CT protocol optimization and AI-based data reconstruction – as well as technologies like photon-counting CT – have enabled imaging professionals to reduce doses to levels previously thought impossible, such as under 1 mSv for a routine chest exam.
To help providers manage dose, CMS this year launched new dose reporting quality measures, CMS1074v2, designed to reward radiology practices for tracking and reporting radiation dose.
- Smith-Bindman is a co-founder of Alara Imaging, which provides software to help radiology providers comply with the new CMS measures. ACR also offers a variety of dose optimization and monitoring tools.
The Takeaway
So what to make of the new study? On the one hand, the sensational headlines it generated could scare many patients away from getting medically necessary CT scans. On the other, any attention toward radiation dose reduction and appropriate imaging is a good thing, and if it spurs new efforts toward more judicious and consistent use of CT at lower radiation levels, so much the better.
