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Finding a Sense of Balance.

Radiation in Medical Imaging Has Its Benefits

For a brief snapshot that shows the power of medical imaging, consider these findings:

  • Use of mammography to screen for breast cancer has resulted in a declining death rate, improved survival rate, and better treatment options1
  • Performing coronary CT angiography to examine the heart vessels in patients with chest pain helps guide treatment decisions with high accuracy and avoids costly invasive procedures2
  • Incorporating advanced medical imaging procedures into healthcare has significantly increased life expectancy in the US3

Radiation in Medical Imaging Has Its Risks

Almost all medical procedures, including imaging procedures that use radiation, have risks associated with them. Physicians and patients should carefully consider the potential benefits and the risks when considering the use of imaging techniques that involve radiation.

Each patient's clinical situation is different, but here are some things for healthcare providers to consider when deciding whether or not an imaging procedure that uses medical radiation is the right choice.

  • What is the purpose of the procedure? For example, is it to arrive at a diagnosis, assess treatment response, or is it preventive screening?
  • Are there alternative imaging procedures that could accomplish the same goal without medical radiation, such as ultrasound or magnetic resonance imaging?
  • What are the risks of not having the imaging procedure done?
  • How old is the patient? The risks for pediatric and adolescent patients may be different than for adults.
  • Is the patient pregnant, possibly pregnant, or breastfeeding?
  • What other procedures is the patient likely to undergo during this workup?
  • What is this person's radiation exposure from previous medical procedures? For example, has the person undergone multiple CT or nuclear medicine scans in the past?
  • What is this person's occupational exposure to radiation, if any?
  • Will the imaging exam be performed on low-dose equipment?

Healthcare providers and their patients are encouraged to discuss these issues and any other potential risks with the treatment team, including the radiologist in charge of supervising the imaging procedure.

Physicians and other healthcare providers can consult their radiology colleagues or a medical physicist for more information.

More information about various procedures can also be found by clicking here.

A Matter of Exposure

The standard unit of measure for radiation absorbed by an individual is called the "Sievert," or Sv (sometimes identified by a smaller unit called the "millisievert," or mSv). Common medical imaging tests such as X-rays or mammograms generally expose patients to a radiation dose of less than 1 mSv. Other procedures using CT, nuclear stress tests, or fluoroscopy-guided exams often involve radiation in the range of 5-40 mSv. New advances in CT technology, like GE Healthcare’s ASiR, have helped reduce the typical range of radiation for CT exams to 1-15 mSv.

Radiation can also be expressed in the unit Gray (Gy), a measurement of the absorbed dose of radiation. This term replaces a former unit of measurement called the rad.

A single exposure at these diagnostic levels may not pose much risk to the patient. But when a patient has numerous tests over a period of time, the cumulative exposure may raise the level of risk. To minimize cumulative exposure, physicians should determine whether a procedure using medical radiation is necessary to achieve the diagnosis or whether an alternative imaging procedure may offer the same diagnostic benefit.

The April 2011 issue of American Journal of Radiology has a series of articles on the assessment of benefits and risks associated with medical radiation in imaging procedures. Healthcare providers can get more details by clicking on the PubMed links below.

 

References:

  1. American Cancer Society. Cancer Facts & Figures 2008. Atlanta: American Cancer Society; 2008.
  2. Budoff MJ, Dowe D, Jollis JG, et al. Diagnostic performance of 64-multidetector row coronary computed tomographic angiography for evaluation of coronary artery stenosis in individuals without known coronary artery disease: results from the prospective multicenter ACCURACY (Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography) trial. J Am Coll Cardiol. 2008;52:1724-1732.
  3. Lichtenberg FR. The quality of medical care, behavioral risk factors, and longevity growth. Int J Health Care Finance Econ. 2011;11:1-34.