According to a new study, patients are receiving estimated doses of radiation from medical diagnostic imaging studies, of that kind as CT (or "CAT") scans, that may be detrimental to their long term health, putting them at an increased risk of developing cancer.

To time, emergency physicians have not been made aware of the cumulative amount of radiation that their patients receive. In fact they currently have no way to know or estimate any given patient’s cumulative dose. A new study hopes to quantify and further explore these concerns.

Led by Timothy B. Bullard, M.D., M.B.A of the Orlando Regional sanatory Center (ORMC), the cross-sectional study examined the amount of ionizing radiation that a random selection of patients received over a five-year period at ORMC and Washington Hospital Center in Washington, D.C. The study is the first to estimate the total continually increasing radiation dosage delivered to a population from multiple diagnostic imaging modalities during a defined period of time.

Patients had an mean proportion cumulative estimated effective radiation dose of 45.0 milliseiverts, with CT scans and nuclear medicine studies contributing the most radiation. Twelve percent of the sample population was estimated to have 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 emergency department population, then a substantial number of people may be placed at increased risk of developing cancer more than 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,” says Bullard. “We also hope that our study will further promote the need for electronic medical records with portability and encourage the development of an individual patient cumulative exposure estimate tool.”

The presentation is entitled “Cumulative Radiation Exposure and Cancer jeopardize from Diagnostic Imaging in Patients Presenting to the Emergency Department.” This paper will be presented at the 2008 SAEM Annual Meeting in Washington, D.C. on May 29, 2008, in the moderated poster session beginning at 3:00 p.m. in Exhibit Hall A of the Marriott Wardman Park Hotel. Abstracts are published in Vol. 15, No. 5, Supplement 1, May 2008 of Academic Emergency Medicine, the official journal of the Society for Academic Emergency Medicine.