Though volume and dose reductions have proven effective in reducing radiation exposure, investments in implementing protocols and new technology have the greatest impact on future cancer risk, according to a study published online March 19 by the Journal of the American College of Radiology.

It has been difficult to discern all the potential factors that have contributed to the reductions in ionizing radiation exposure. Lead author Michael F. Rayo, PhD, of the Ohio State University in Columbus, and colleagues aimed to determine the impact of changes in CT procedure volumes and dose reduction interventions on possible future cancer risk for the inpatient population at an academic medical center. Patients underwent CT scans of the abdomen, head, sinus, and lumbar spine.

Once the researchers calculated annual CT volume, rate, average effective dose, radiation exposure, and estimated cancer risk for general medicine and intensive care unit patients, they discovered a 37 percent reduction in abdominal CT volume from 2008 to 2012. Importantly though, these reductions were not evident for CT exams of the head or lumbar spine.

Results also revealed a 30 to 52 percent decrease in radiation exposure from dose reduction strategies in the targeted body areas. A 63 percent reduction in estimated induced cancers was reached through the combination of volume and dose reductions.

Implemented dose reduction strategies were observed as the predominant catalyst behind the effective dose reduction from 23.2 to 8.6 mSv per patient, the dip in patients with annual effective doses less than 50 mSv that went from 10 to 0.2 percent, predicted induced cancers that decreased from 10.1 to 3.8, and the decline in predicted cancer deaths from 5.1 to 1.9.

“These findings suggest that although efforts should continue in trying to reduce inappropriate diagnostic imaging for both cost and patient safety reasons, implementing protocol and technology improvements may be more effective in reducing patients' effective radiation dose and estimated future cancer risk,” concluded Rayo and colleagues.