What New Research Reveals About Computed Tomography and Radiation-Induced Cancer Risk

A new study estimates that computed tomography (CT) exams performed in the United States in 2023 will lead to over 100,000 future cases of radiation-induced cancer.

For the study, published today in JAMA Internal Medicine, researchers reviewed data from an estimated 93,000,000 CT exams performed in 2023 for an estimated 61,510,000 patients, including 58,940,000 adults and 2,570,000 children, as well as data from the University of California San Francisco (UCSF) International CT Dose Registry.

Based on current use and radiation dosing levels with CT exams, the study authors estimated that exposure to CT exams performed in 2023 will lead to radiation-induced cancer in 103,000 patients.

While acknowledging that the risk of radiation-induced cancers with CT scans is relatively low, lead study author Rebecca Smith-Bindman, M.D., in a recent interview, emphasized that the projection of radiation-induced cancers is a significant number when considering other risk factors for cancer.

“If we look in the context of cancer in general, if these (CT) dosing practices and utilization practices continue, CT will account for a ballpark of 5 percent of all cancers,” noted Dr. Smith-Bindman, the director of the Radiology Outcomes Research Laboratory and a professor of epidemiology and biostatistics at the UCSF School of Medicine.

“It's not 95 percent, it's not 50 percent but it's a meaningful (number), and it's a number that's comparable to other cancer risk factors that we really think about (like) alcohol consumption (and) obesity, (that) both account for five to 7 percent of cancer. So those are modifiable risk factors that we want to modify to reduce cancers. CT scanning is in that category.”

Dr. Smith-Bindman noted that abdominal and pelvic CT exams accounted for 32 percent of the total number of CT exams in 2023 and were projected to cause 37 percent of the estimated future cases of radiation-induced cancer. Extraneous use of multi-phase scans for routine abdominal CT could be a key target, according to Dr. Smith-Bindman.

“Reducing those multiple phase scans could have a huge impact on reducing the number of future cancers,” maintained Dr. Smith-Bindman.

(Editor’s note: For related content, see “Deep Learning Denoising May Facilitate Up to a 75 Percent Reduction in Radiation Dosing for Head CT,” “Can AI Facilitate Single-Phase CT Acquisition for COPD Diagnosis and Staging?” and “Emerging Strategies for Managing the Acute Shortage of Iodinated Contrast Media.”)

(Editor's note: Graphic in video courtesy of JAMA Internal Medicine.)

For more insights from Dr. Smith-Bindman, watch the video below.