It's well known that excessive amounts of radiation have deleterious effects on health, especially in the long term. In a recent retrospective cohort study, researchers sought to estimate the doses of radiation nonelderly patients incur from medical imaging procedures.

The researchers obtained data on more than 952,000 patients, ages 18 to 64 years, from five different health care markets in the United States who had policies with a large national insurance company. The numbers and types of medical-imaging procedures completed were evaluated from insurance claims that contained codes specific to the use of radiation-related imaging procedures (therapeutic uses of radiation, such as in breast cancer treatment, were not included).

Approximately 69% of the study population (n = 655,613) had undergone a medical imaging procedure during the three-year study period. In total, nearly 3.5 million procedures were conducted, amounting to a mean of 1.2 procedures per person per year. The cumulative effective dose of radiation (a dose "'as low as reasonably achievable' without sacrificing quality of care") was a mean of 2.4 millisieverts (mSv) per person per year, an amount considered low. However, 19.4% of patients experienced moderate levels (from 3 to 20 mSv per year), 1.86% experienced high levels (from 20 to 50 mSv per year), and 0.19% experienced very high levels (more than 50 mSv per year). (In comparison, health care workers performing radiation-related procedures and employees in nuclear facilities aren't allowed to average more than 20 mSv of radiation exposure per year, and not more than 50 mSv in any given year.)

The percentage of patients who underwent one or more procedures increased with each successive age group: 49.5% of those 18 to 34 years old had at least one procedure, as did 85.9% in the oldest group (60 to 64 years). Women across all age groups underwent more procedures-and were exposed to more radiation-than men in the same respective age groups. Computed tomographic and nuclear imaging procedures accounted for three-fourths of the cumulative effective dose seen in the study, and the vast majority of procedures (81.8%) were performed on an outpatient basis.

The study highlights the need for judicious use of medical imaging procedures and better training of health professionals, including radiologists, in the long-term dangers of radiation used in imaging.

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