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Description
Cardiac computed tomography (CCT) is widely used for non-invasive coronary artery assessment; however, it involves direct irradiation of the anterior chest, where breast tissue is located. Therefore, breast tissue receives a relatively higher absorbed dose compared with many other CT examinations that may contribute to cancer risks. This study evaluated patient radiation doses, effective doses and estimated cancer risks among 47 patients undergoing cardiac CT at King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia. Effective dose was estimated using a cardiac-specific conversion coefficient (0.014 mSv/mGy·cm). The mean effective dose was 5.56 ± 4.42 mSv, with a median of 4.49 mSv and a range of 0.05–15.40 mSv. Approximately 75% of patients received less than 9.53 mSv. The estimated average glandular dose is 7.0–8.5 mGy. Patient doses showed wide variation due to variability in scanning protocols, patient body habitus, and procedural complexity. Lifetime attributable cancer risk was estimated using a nominal risk coefficient of 5% per Sv. The mean and range of the estimated cancer risk per CCT examination was 0.028% (0.00027–0.077%). The estimated excess lifetime breast cancer risk was 0.09% Although individual risk from a single cardiac CT examination remains low, cumulative risk may increase with repeated imaging, particularly in younger female patients. The wide range of patient doses indicate that patient dose not optimized yet. Establishment of diagnostic reference levels with implementation of dose saving protocol will help in patient dose reduction and eliminate the unnecessary radiogenic cancer risks.