Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography.
BACKGROUND
Computed tomography coronary angiography (CTCA) has become a common diagnostic test, yet there are little data on its associated cancer risk. The recent Biological Effects of Ionizing Radiation (BEIR) VII Phase 2 report provides a framework for estimating lifetime attributable risk (LAR) of cancer incidence associated with radiation exposure from a CTCA study, using the most current data available on health effects of radiation.


OBJECTIVE
To determine the LAR of cancer incidence associated with radiation exposure from a 64-slice CTCA study and to evaluate the influence of age, sex, and scan protocol on cancer risk.


METHODS
Organ doses from 64-slice CTCA to standardized phantom (computational model) male and female patients were estimated using Monte Carlo simulation methods, using standard spiral CT protocols. Age- and sex-specific LARs of individual cancers were estimated using the approach of BEIR VII and summed to obtain whole-body LARs.


METHODS
Whole-body and organ LARs of cancer incidence.


RESULTS
Organ doses ranged from 42 to 91 mSv for the lungs and 50 to 80 mSv for the female breast. Lifetime cancer risk estimates for standard cardiac scans varied from 1 in 143 for a 20-year-old woman to 1 in 3261 for an 80-year-old man. Use of simulated electrocardiographically controlled tube current modulation (ECTCM) decreased these risk estimates to 1 in 219 and 1 in 5017, respectively. Estimated cancer risks using ECTCM for a 60-year-old woman and a 60-year-old man were 1 in 715 and 1 in 1911, respectively. A combined scan of the heart and aorta had higher LARs, up to 1 in 114 for a 20-year-old woman. The highest organ LARs were for lung cancer and, in younger women, breast cancer.


CONCLUSIONS
These estimates derived from our simulation models suggest that use of 64-slice CTCA is associated with a nonnegligible LAR of cancer. This risk varies markedly and is considerably greater for women, younger patients, and for combined cardiac and aortic scans.
Einstein
Andrew J
AJ
Department of Medicine, Division of Cardiology and Department of Radiology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA. andrew.einstein@columbia.edu
Henzlova
Milena J
MJ
Rajagopalan
Sanjay
S
D000328:Adult; D017023:Coronary Angiography / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009010:Monte Carlo Method; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D019047:Phantoms, Imaging; D011874:Radiometry; D012306:Risk; D036542:Tomography, Spiral Computed / Q000009:adverse effects*