1. Typical effective radiation doses are provided for coronary computed tomography angiography, calcium score, single-photon emission computed tomography (SPECT), PET, diagnostic fluoroscopy, and interventional fluoroscopy studies. Many of these have wide ranges of typical effective doses (e.g., SPECT can range from 2.3 to 23 mSv).
2. Population exposure to medical radiation has grown rapidly and was reported as 3.2 mSv/year when last estimated in 2006. This exceeds the natural background radiation that averages 3.0 mSv/year in the United States.
3. Physicians performing interventional cardiovascular procedures can be exposed to significant radiation, which can exceed 100 uSv for a single procedure. An active interventional cardiologist can be expected to receive as much as 10 mSv/year of radiation in addition to background radiation.
4. Doses over 100 mSv are associated with increased cancer risk in adults, with smaller doses associated with risk in children. Some patients and some physicians may be exposed to lifetime exposures that exceed this threshold.
5. Effective radiation dose is estimated by measuring the radiation dose to specific tissues and organs, and adjusting this using a weighting factor that incorporates the sensitivity of each tissue and organ to cancer risk.
6. Radiation risks can include tissue reactions due to cell injury (e.g., skin injuries), cancer, and mutations to germ cells that may be transmitted to offspring.
7. The most accepted model of cancer risk suggests a linear relationship between dose and cancer risk, with no dose threshold under which there is no risk.
8. Increased cancer risk is associated with higher doses, exposure of radiation-sensitive organs, female gender, and younger age. The predicted lifetime risk of cancer from exposure to 100 mSv of radiation is estimated at 2% for males and 4% for females under 15 years of age, and this risk decreases with greater age.
9. Recommended radiation limits for workers exposed to occupational radiation are 20 mSv/year averaged over 5 years.
10. The ALARA concept is that radiation dose should always be “as low as reasonably achievable.