How much radiation exposure will I have from a heart test?

Anthony L. Komaroff, MD
Internal Medicine
Many tests used to diagnose heart disease involve radiation exposure, which is measured in millisieverts (mSv), a designation that reflects the biological effect of radiation on tissues. Radiation offers extraordinary benefits for diagnosing heart disease and other ailments, but it can cause damage to cells that may trigger cancer. Each year, the average person receives about 3 mSv of so-called background radiation from naturally occurring sources of radiation from the Earth and cosmos. This tiny amount has little effect on health. But since the 1980s, the amount of radiation used in medicine has grown so much it now rivals background radiation, adding an average 3 mSv per person each year, says the National Council on Radiation Protection and Measurement. Much of this growth comes from computed tomography (CT) scans.

The amount of radiation from these scans varies widely, according to a report in The Journal of the American Medical Association (JAMA). Researchers estimated exposures from CT scans at 50 hospitals worldwide and found levels at the highest-dose sites to be six times as high as those at the lowest doses. The variability stemmed from differences in scanner models, how the machine was operated, and whether radiation-reducing techniques were used. The average radiation exposure from a single new-generation test was equal to the exposure from 600 conventional chest x-rays.

The following are estimated amounts of radiation exposure from some common heart tests:
  • coronary calcium scan, 1 - 3 mSv
  • 64-slice cardiac CT, 7 - 23 mSv
  • 320-slice cardiac CT, 10 - 18 mSv
  • technetium stress test, 6 - 15 mSv
  • thallium stress test, 17 mSv
  • dual isotope stress test, 18 - 38 mSv
  • angiogram, 2 - 23 mSv

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.