, Volume 15, Issue 2, pp 232-240

Radiation dose and cancer risk estimates in 16-slice computed tomography coronary angiography

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Abstract

Background

Recent advances have led to a rapid increase in the number of computed tomography coronary angiography (CTCA) studies performed. Whereas several studies have reported the effective dose, there are no data available on cancer risk for current CTCA protocols.

Methods and Results

Effective and organ doses were estimated, by use of scanner-derived parameters and Monte Carlo methods, for 50 patients having 16-slice CTCA performed for clinical indications. Lifetime attributable risks were estimated with models developed in the National Academies’ Biological Effects of Ionizing Radiation VII report. The effective dose of a complete CTCA averaged 9.5 mSv, whereas that of a complete study, including calcium scoring when indicated, averaged 11.7 mSv. Calcium scoring increased effective dose by 25%, whereas tube current modulation reduced it by 34% and was more effective at lower heart rates. Organ doses to the lungs and female breast were highest. The lifetime attributable risk of cancer incidence from CTCA averaged approximately 1 in 1,600 but varied widely among patients, being highest in younger women. For all patients, the greatest risk was from lung cancer.

Conclusions

CTCA is associated with non-negligible risk of malignancy. Doses can be reduced by careful attention to scanning protocol.

This study was presented in part at the American College of Cardiology 55th Annual Scientific Session, Atlanta, Ga, March 13, 2006.
This work was supported in part by a National Institutes of Health/National Center for Research Resources Clinical and Translational Science Award (1 UL1 RR-24156-01).