Significant increase in use of CT, MRI and PET imaging over the last two decades

The authors also found that the increase in the utilization of CT was associated with an increase in estimated exposure to radiation, with the average per capita effective dose increasing from 1.2 mSv in 1996 to 2.3 mSv in 2010. The percent of enrollees who received high (> 20-30 mSv) or very high (> 50 mSv) radiation exposure during a given year also approximately doubled across study years. The researchers also estimated that by 2010, 2.5 percent of enrollees received a high annual dose of greater than 20 to 50 mSv, and 1.4 percent received a very high annual dose of greater than 50 mSv. By 2010, 6.8 percent of patients who underwent imaging received a high dose of more than 20 to 50 mSv and 3.9 percent of patients received a very high dose above 50 mSv during this single year.

The researchers write that the "increase in imaging use over this period was likely driven by many factors, including improvements in the technology that have led to expansion of clinical applications, patient- and physician-generated demand, defensive medical practices, and medical uncertainly—all factors that would be expected to influence utilization across all systems of medical care."

"The increase in use of advanced diagnostic imaging has almost certainly contributed to both improved patient care processes and outcomes, but there are remarkably few data to quantify the benefits of imaging. Given the high costs of imaging—estimated at $100 billion annually—and the potential risks of cancer and other harms, these benefits should be quantified and evidence-based guidelines for using imaging should be developed that clearly balance benefits against financial costs and health risk."

Source JAMA