The Truth About Radiation Risks From Medical Imaging

Much has been written in recent years about the potential harm from radiation associated with medical imaging, such as CT Scans.  These sources have tended to assume as proven fact that the radiation doses associated with medical imaging are harmful while also tending to neglect the potential benefits from those procedures.

On December 13, 2011, the American Association of Physicists in Medicine (AAPM) released their Position Statement on Radiation Risks from Medical Imaging Procedures.  AAPM is a scientific and professional organization dedicated to ensuring the safety and quality of radiation in medical procedures.  They are one of the most authoritative voices in the field of medical radiation and its benefits and risks.

The AAPM statement affirms the following points:

  • Medical imaging procedures should be appropriate and conducted at the lowest radiation dose consistent with acquisition of the desired information.
  • Discussion of risks related to radiation dose from medical imaging procedures should be accompanied by acknowledgement of the benefits of the procedures.
  • Risks of medical imaging at effective doses below 50 mSv for single procedures or 100 mSv for multiple procedures over short time periods are too low to be detectable and may be nonexistent.
  • Predictions of hypothetical cancer incidence and deaths in patient populations exposed to such low doses are highly speculative and should be discouraged.
  • These predictions are harmful because they lead to sensationalistic articles in the public media that cause some patients and parents to refuse medical imaging procedures, placing them at substantial risk by not receiving the clinical benefits of the prescribed procedures.

Many of the articles we have seen in the media cite dose for a single CT scan as high as 25 mSv.    While there may be imaging centers that still routinely expose patients to doses that high, improvements in technology coupled with careful attention to techniques for minimizing dose have resulted in dramatically lower radiation doses in recent years.

For example, atPrincetonLongevityCenterthe average dose for a Coronary Calcium Heart Scan is about 1.5 mSv and is often as low as 0.7 mSv.  The dose for a Cardiac CT Angiography average 3 mSv and is often less than 1.0 mSv.  A typical Full Body Scan will average 5-7 mSv.

These doses are substantially lower than the 50 mSv threshold for which AAPM’s experts say the risks may be too low to be detected.

As with any medical procedure, the risks and benefits must be carefully weighed in order to make an informed decision.  The statement by AAPM is helpful in clarifying that the risks of radiation are frequently overstated while the benefits of early disease detection and more precisely guided therapy afforded by medical imaging are often insufficiently considered.