Estimating the risks of exposure-induced death associated with common computed tomography procedures

Background: This study aimed to assess the risks of exposure-induced death (REID) in patients and embryos during CT examinations in Yazd province (Iran). Materials and Methods: Data on the exposure parameters were retrospectively collected from six imaging institutions. In total, 932 patients were included in this study and for each patient, organ doses were then estimated using ImpactDose software. The REIDs were calculated by BEIR VII risk model and using PCXMC software. In the case of gestational irradiation, excess cancer risk of 0.006% per mSv was taken into account in terms of the ICRP 84 recommendations, to calculate the excess childhood cancer risk imposed on the embryo. Results: The highest estimated organ doses for abdomen-pelvis, routine chest, chest HRCT, brain, and sinus examinations were obtained as 12.82 mSv for kidneys, 12.09 mSv for thymus, 13.16 mSv for thymus, 29.71 mSv for brain, and 11.70 mSv for oral mucosa, respectively. Across all procedures, abdomen-pelvis CT scan induced the highest excess REID to the patients (240 deaths per million). The highest delivered dose to the fetus was roughly 35 mSv, which was lower than the threshold dose proposed by ICRP (100 mSv) for the induction of malformations. However, the associated excess fatal childhood cancer risk of 2122 incidence per million scans can be a subject of concern for public health experts. Conclusion: Based on the results, although death risks related to induced cancer from CT scans were negligible, this risk can be relatively significant for children exposed during the fetal period.