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Collaboration among institutions lowers total CT radiation dose

Sharing best practices on dose-optimization and providing audit feedback across different institutions meaningfully lowered or stabilized radiation doses for chest, abdominal and head CT, according to research published in JAMA Internal Medicine.

“Despite a steady increase in the use of CT in the past 2 decades, there are few concrete standards for radiation doses,” Joshua Demb, MPH, from the department of epidemiology and biostatistics at the University of California, San Francisco, and colleagues wrote. “The American College of Radiology and other organizations promote performing CT scans with radiation exposures that are as low as reasonably achievable. However, in the absence of explicit definitions of achievable standards, radiation doses from CT examinations vary widely both within and across institutions. This variability suggests opportunity for improvement.”

Demb and colleagues performed a before/after interventional study to investigate whether dose auditing and sharing best practices on CT radiation doses leads to optimization of radiation dose among five University of California medical centers. The researchers collected radiation dose metrics on all diagnostic CT examinations conducted from Oct. 1, 2013 and Dec. 31, 2014. They created audit reports describing the distribution of radiation dose metrics for chest, abdomen and head CT scans using data from January to March. These reports were shared with the medical centers in April. Radiology professionals from the centers were then invited to a 1.5-day in-person meeting to review the reports and share best practices. Changes in mean effective dose 12 weeks before and after the audits and meeting, not including the 12-week implementation period, were measured.

During the study period, 158,274 diagnostic CT scans were performed; of those, 29,594 CT scans were performed in the 3 months before and 32,839 CT scans were performed 12 to 24 weeks after the audit and meeting. Results indicated that for chest and abdomen, there were considerable reductions in mean effective dose.

There was a decline from 13.2 mSv to 10.7 mSv in mean effective dose for chest CT (18.9% reduction; 95% CI, 18-19.8). Across medical centers, this reduction in mean effective dose ranged from 3.8% to 23.5%.

For abdominal CT, there was a decline from 20 mSv to 15 mSv in mean effective dose for chest CT (25% reduction; 95% CI, 24.3-25.8). This reduction in mean effective dose ranged from 10.8% to 37.4% across medical centers.

There was a considerable reduction in the number of CT scans that had an effective dose measurement that exceeded benchmarks for chest (48%) and abdomen (54%). Although head CT doses did not vary as much after the audit and meeting, mean head CT doses and the proportion above benchmark were increased by some institutions and decreased by others, according to the researchers.

“Reducing unnecessary variation in radiation dose across hospitals and imaging facilities is a complex but important process for improving patient safety,” Demb and colleagues concluded. “This study indicated that inclusion of dose audit data can lead to lower and more consistent CT doses. Importantly, bringing health professionals together to discuss best practices after receipt of a site-specific audit report can change the approach to dose management and optimization, which could effectively lower CT doses.” – by Alaina Tedesco

Disclosure: The researchers report receiving support from the NIH National Cancer Institute, the Patient-Centered Outcomes Research Institute and the University of California Office of the President Center for Health Quality and Innovation.