Cumulative radiation exposure with imaging shows increased cancer risk
Patients are receiving cumulative doses of radiation from medical diagnostic imaging studies, such as CT scans, that may be detrimental, putting them at an increased risk of developing cancer, according to a new study at the Orlando Regional Medical Center in Orlando, Fla.

The researchers said that emergency department (ED) physicians have not been made aware of the cumulative amount of radiation that their patients receive. The ED physicians currently have no way to know or estimate any given patient’s cumulative dose, and the investigators undertook the study with hopes of quantifying and further exploring the concerns.

Timothy B. Bullard, MD, and colleagues examined the amount of ionizing radiation that a random selection of patients received over a five-year period at ORMC and Washington Hospital Centre in Washington, D.C, in the cross-sectional study.

The study is the first to estimate the total cumulative radiation dosage delivered to a population from multiple diagnostic imaging modalities during a defined period of time, according to researchers.

Patients had an average cumulative estimated effective radiation dose of 45 milliseiverts, with CT scans and nuclear medicine studies contributing the most radiation, the authors wrote.

The investigators estimated that 12 percent of the sample population received 100 or more millisieverts of radiation, a value that exceeds the accepted threshold of safety for exposure to low-level ionizing radiation.

If study patients are representative of the general ED population, then Bullard and colleagues concluded that a substantial number of people may be placed at increased risk of developing cancer over their lifetime from diagnostic imaging studies as a result of these exposures.

“Our research hopefully will affect the habits of physicians who routinely order medical imaging diagnostic studies in their practices,” said Bullard. “We also hope that our research will further promote the need for electronic medical records with portability and encourage the development of an individual patient cumulative exposure estimate tool.”