Radiation-related cancer risks in a clinical patient population undergoing cardiac CT.
OBJECTIVE
The purpose of our study was to estimate cancer induction risk and generate risk conversion factors in cardiac CT angiography.


METHODS
Under an institutional review board waiver and in compliance with HIPAA, we collected characteristics for a consecutive cohort of 100 patients (60 men and 40 women; mean age, 59 ± 11 years) who had previously undergone ECG-gated cardiac CT angiography on a 64-slice CT scanner. The volume CT Dose Index (CTDI(vol)) and dose-length product (DLP) were recorded and used with the ImPACT CT Patient Dosimetry Calculator to compute organ and effective doses in a standard 70 kg phantom. Patient-specific organ and effective doses were obtained by applying a weight-based correction factor. Radiation doses to radiosensitive organs were converted to risks using age- and sex-specific data published in BEIR VII.


RESULTS
Median values were 62 mGy for CTDI(vol), 1,084 mGy-cm for DLP, and 17 cm for scan length. Effective doses ranged from 20 mSv (10th percentile) to 31 mSv (90th percentile). Median cancer induction risks in sensitive organs for men and women were 0.065% and 0.17%, respectively. For men and women, the range of risks was about a factor of 2. In men and women, about three quarters of the cancer risk was from lung cancer. Inclusion of the remaining less sensitive organs exposed during cardiac CT angiography examinations would likely increase the cancer induction risk by ∼20%.


CONCLUSIONS
The average cancer induction risk in sensitive organs from cardiac CT angiography for our patient cohort was 0.13%, with a female to male cancer induction risk ratio of 2.6.
Department of Radiology and Radiological Sciences, Medical University of South Carolina, 96 Jonathan Lucas Street, MSC 323, Charleston SC 29425-3230, USA.
Walter
W
Huda
U Joseph
UJ
Schoepf
Joseph A
JA
Abro
Eugene
E
Mah
Philip
P
Costello
D000328:Adult; D000368:Aged; D001822:Body Burden; D015331:Cohort Studies; D017023:Coronary Angiography / Q000009:adverse effects* / Q000706:statistics & numerical data; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D018570:Risk Assessment / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000009:adverse effects* / Q000706:statistics & numerical data