Study Lessens Concerns Radiation Exposure During Cardiac CT
A study presented at the European Society of Radiology meeting in Vienna indicates that the risk of developing radiation-induced malignancy is substantially lower than has been previously reported. CT imaging has been somewhat controversial of late, with some experts suggesting that use of imaging technology can increase the risk of patients developing radiation-induced cancers. This concern was significant enough that some suggested decreased use of imaging modalities that require higher levels of radiation. Information about the new data presented was posted by Diagnostic Imaging.
The research was conducted by a team at the Medical University of South Carolina (MUSC). Over 100 patients consecutively treated were recruited to participate; 64 of whom were men. All patients had cardiac CT completed with a 64-slice scanner.
The team calculated doses to patients’ organs with the ImPACT dosimetry spreadsheet, calculations were later corrected to account for patients’ weight. Risk of developing malignancy was determined with the BEIR VII approach. This model is based on data from Japanese persons who survived the atomic bomb.
The average risk was 0.12 percent. Risk of mortality was estimated to be 0.1 percent. Lung cancer was projected to be the most likely source of malignancy-related mortality; lung cancer represents 85 percent of radiation-induced cancer. Risk of disease was, however, higher amongst the patients who weighed less, were younger, or exposed to a higher dose of radiation.
These findings differ markedly from a report previously published in the Journal of the American Medical Association. That study suggested that the risk of developing these types of cancers is one in 114. That research team calculated risk using presumed scan protocols for an average 20 year old female patient.
The South Carolina team noted factors that may explain the differences in the two risk calculations. First of all, most patients who undergo CT scanning of the heart are somewhere between 50 and 70 years old. As well, the patient population at MUSC was heavier than the population reported in JAMA. Heavier patients have a lower risk of developing radiation-induced cancers.
The team suggests that the diagnostic utility of CT outweighs potential risks from radiation when the imaging technique is used appropriately. Key tools to protect patients from unnecessary exposure to radiation include indication for the scan and patient selection. An article posted on Diagnostic Imaging last November details some of the practical means to reduce radiation exposure for those patients who do undergo scans, which was posted on HospitalBuyer.
March 17, 2008 Related topics: Materials Management