Radiology and cardiovascular researchers from the Medical University of South Carolina in Charleston, S.C., also said that the new estimates are several times lower than previously published conclusions.
In earlier studies, many scientists claimed that the risk of cancer from radiation exposure during CT for cardiovascular disease was approximately 1 in 114, but the new study suggests that the risk is 1 in 1000.
U. Joseph Schoepf, MD, and colleagues from MUSC, have said that previous studies assessing lifetime risks of cancer from radiation in cardiac CT are based on unreliable models of patients who undergo CT for cardiovascular disease.
For the study, the researchers examined 104 consecutive patients undergoing 64-slice cardiac CT at the Medical University of South Carolina. The majority of the patients were male with median age of 59 and median weight of 202 pounds.
The team converted organ radiation doses into risk using a previously published and validated measure. Patient cancer risks were adjusted taking into account patient sex, age and weight, the latter being an often neglected factor influencing radiation risk.
Scheopf said that the new risk in this patient population, which mirrors more closely the typical patients who receive cardiac CT, was 1 in 1000.
"Thus, in a real-life clinical patient group, the realistic risk of radiation induced cancer from cardiac CT is substantially lower than previously reported for general populations," said Scheopf.
He added that radiation exposure is a serious issue and patients need to talk to their doctors before undergoing any tests that exposes them to radiation to ensure the test is appropriate and the patient fits under patient selection guidelines published by the American Heart Association and the American College of Radiology.
The findings of the study were presented at the annual meeting of the Radiological Society of North America in Chicago.