Purpose: To compute ICRP‐103 based gender and age specific (baby, child, adult) normalized effective dose conversion k‐factors (mSv/mGy*cm) for clinically relevant CT scanned body regions. Methods: We used the program CTExpo‐v2.0 to compute DLP‐to‐effective dose k‐factors for the scan ranges used clinically for examinations of the head, orbits/temporal bones, maxillofacial, head/neck, neck,
... [Show full abstract] chest, abdomen, chest/abdomen, chest/abdomen aorta, pelvis, abdomen/pelvis, chest/abdomen/pelvis, and chest/abdomen/pelvis aorta. The mathematical models of “baby”, “child”, “EVA”, and “ADAM” were used with the current ICRP‐103 tissue weighting factors as well as the previous ICRP‐60 weighting factors. We used three CT scanner models, one from each of the most popular manufacturers, with 20‐mm total beam collimation and helical pitch of 1. Results: Except for the head, the k‐factors for the adult male are lower than the female by up to ∼33% (chest). For the head, the k‐factor for the adult male model is ∼10% higher than the female. The maximum ICRP‐103 to ICRP‐60 based k‐factor ratio is ∼1.35 for “baby” head, and the minimum is ∼0.6 for “baby” pelvis. We compared our ICRP‐103 based k‐factor estimates for adult models with the similar, but hermaphrodite model estimates of Huda et al. (Medical Physics, March 2011.) The largest difference (40 – 46%) was observed for the female abdomen scan range. For the female chest, our estimates are 17 – 21 % higher than the ones of Huda et al. For the male chest, our estimates are 19 – 23% lower. For the male chest/abdomen/pelvis our estimates are 14 – 18% lower. Conclusions: The k‐factors for adult and female models differed by as much as 33%. ICRP‐ based k‐factors differed from ICRP‐60 based k‐factors by as much as +35% to ‐40%. Finally, some significant differences were observed for certain gender specific scan ranges between the present work and that of Huda et al.