The global increase in the number of computed tomography (CT) examinations have enhanced concerns regarding stochastic radiation risks to patients, especially for children. Considering that cancer risk is cumulative over a lifetime and each CT examination contributes to the lifetime exposure, there is a need for a better understanding of radiation-induced cancer incidence and mortality, and better dose estimates. Accordingly, some authors estimated organ and effective dose in reference phantoms, but still there is a critical need to expand these data to larger groups of non-reference children. As an initial step to address this issue, in this study organ and effective doses were calculated in common CT procedures in non-reference pediatric phantoms and were compared with those of reference phantoms with the similar ages. Thirteen pediatric phantoms, BABY CHILD, five voxel-based UF pediatric phantoms (B-series) and six phantoms developed at The Foundation for Research on Information Technologies in Society (IT’IS) were implemented into MCNP. According to the results, there were no consistent differences between the doses of organs exposed indirectly and effective doses of these three phantom types, but it was observed that for organs located in the scan region, there was a relation between absorbed doses and pediatric age group, as expected. Generally, using the results of this study one can estimate the absorbed doses more accurately. But it should be noted that these low expansion data are not comprehensive enough for finding a reasonable relationship between phantom size and effective dose except in chest-abdomen-pelvis (CAP) imaging.

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