May 6, 2009

Patient’s CT scans should be monitored

Physicians should review a patient's computed tomography imaging history and cumulative radiation dose before doing another CT exam, U.S. researchers say.

The study of 130 patients who had at least three emergency department visits within one year, published in the American Journal of Roentgenology, found that half had undergone 10 or more CT scans in the previous eight years, up to a maximum of 70 CT scans.

Researchers at Brigham and Women's Hospital in Boston and Washington University School of Medicine, St. Louis said a patient's cumulative risk of radiation-induced cancers is believed to increase with cumulative radiation dose and the level of risk is further increased for patients scanned at young ages and is in general greater for women than for men.

Using typical dose values and standard risk estimation methods, we calculated that half of our group had accrued additional radiation-induced cancer risks above baseline greater than 1 in 110, up to a maximum of 1 in 17, Dr. Aaron Sodickson says in a statement.

There is no absolute threshold and the potential risks of radiation induced cancer must be balanced against the expected clinical benefits of the CT scan for the patient's particular scenario.