MONDAY, Feb. 7 (HealthDay News) -- Heart attack patients who are exposed to low-dose radiation from cardiac imaging and other procedures may have an increased risk of cancer, a new study finds.

Canadian researchers analyzed data from 82,861 patients who survived a heart attack between April 1996 and March 2006 and had no history of cancer. Within one year of their heart attack, 77 percent of the patients underwent at least one cardiac procedure with low-dose ionizing radiation, such as CT angiography and nuclear scans.

Patients treated by a cardiologist had higher levels of exposure to radiation than those treated by a general practitioner, the study authors noted.

During follow-up, there were 12,020 cancers detected among the patients, with two-thirds of the cancers affecting the abdomen/pelvis and chest areas.

"We found a relation between the cumulative exposure to low-dose ionizing radiation from cardiac imaging and therapeutic procedures after acute myocardial infarction [heart attack], and the risk of incident cancer," wrote Dr. Louise Pilote, an epidemiology researcher at the Research Institute of the McGill University Health Center (MUHC) in Montreal, and director of the internal medicine division at MUHC, and colleagues.

"Although most patients were exposed to low or moderate levels of radiation, a substantial group were exposed to high levels and in general tended to be younger male patients with fewer comorbidities [co-existing health problems]," they added.

"These results call into question whether our current enthusiasm for imaging and therapeutic procedures after acute myocardial infarction should be tempered," the researchers concluded. "We should at least consider putting into place a system of prospectively documenting the imaging tests and procedures that each patient undergoes and estimating his or her cumulative exposure to low-dose ionizing radiation."

The study appears in the current issue of the Canadian Medical Association Journal.

More information

The American College of Radiology and the Radiological Society of North America outline the risks and benefits of radiological procedures.