With repeated requests from patients for more and more radiologic studies, are there any data documenting the side effects of radiation due to continued and increased exposure to CT scans, x-rays, etc.?
—FELIX N. CHIEN, DO, Newport Beach, Calif.

There are limited data. I did find one study that predicted the absolute number of cancer deaths attributable to one year of CT examinations in the United States (based on the 1995 U.S. CT scan rate of 91 tests per 1,000 people per year) at approximately 700 from head imaging and 1,800 from abdominal imaging (AJR Am J Roentgenol. 2001;176:289-296). Notably, this study included data from pediatric patients, who may be more sensitive to the effects of radiation exposure than adults.
—Daniel G. Tobin, MD