Mahadevappa Mahesh, Ph.D., chief of medical physicist and professor of radiology and medical physics, Johns Hopkins University, Baltimore, treasurer of the American Association of Physicists in Medicine (AAPM),a board member of the American College of Radiology (ACR), presented a late-breaking study on how medical imaging radiation dose has started to drop over the past decade. He is the co-chair of the National Council on Radiation Protection and Measures Report (NCRP), and presented the most recent NCRP data analysis at the 2019 Radiological Society of North America (RSNA) meeting.
The new NCRP 184 report covers the period between 2006 and 2016, the period of the most current CMS data. It shows a decrease of about 20 percent in the radiation dose the U.S. population receives from medical imaging, compared to the NCRP 160 that covered the period of up to 2006.
Key findings of the study include:
• CT dose dropped about 6 percent, despite a 20 percent increase CT scans since 2006;
• Drop of more than 50 percent for nuclear imaging scans, mainly due to fewer procedures begin performed;
• A 15-20 percent decrease across X-ray imaging modalities.
Mahesh says this shows the impact of using "as low as reasonably achievable" (ALARA) principals, new dose guidelines outlined jointly by numerous medical societies, and dose reduction initiatives like Image Wisely, Image Gently, and the American College of radiology (ACR) Dose Index Registry.
He said there was growing concern a decade ago when the last council report was published, which show a steep increase in radiation dose. This was mainly due to a rapid increase in the use of computed tomography (CT) and other types of X-ray based and nuclear radiotracer medical imaging. This prompted the ACR top create the Image Wisely program and push for the use of more thoughtful imaging doses based on patient size, using the "as low as reasonably achievable” (ALARA) principle. While CT dose was lowered, he said the biggest decline was in nuclear imaging.