An analysis of insurance claims of almost 1 million adults revealed that about two-thirds had at least one medical imaging test during which they were exposed to moderate-to-high doses of radiation. This was observed during the study period.

Nuclear imaging and computed tomography scans delivered the maximum radiation. These scans are usually done to check for heart disease.

"We don't want to scare people and have them refuse necessary procedures, but physicians and patients need to be aware that radiation is not benign," study researcher Reza Fazel, MD, of Atlanta's Emory University School of Medicine, tells WebMD. "Our study shows that a lot of people are getting high doses of radiation."

Government estimates also suggest that the radiation doses have increased sixfold since the 1980s as the number of scans performed to monitor and diagnose a huge number of diseases have gone up.

The radiation exposure is measured in millisieverts (mSv). An exposure of more than 20 mSv is considered very high while 3mSv to 20 mSv is a moderate level of exposure.

The real challenge that now stands is to identify which tests add value for the diagnosis and management of disease and which of these do not.