| Positron emission tomography (PET)/computed tomography (CT) is a wellknown
modality for the diagnosis of various diseases in children and adult
patients. On the other hand, younger patients are more radiosensitive than
adults, so there are concerns about the level of ionizing radiation exposure in
pediatric whole body PET/CT imaging. In this regard, comprehensive specific
radiation dosimetry for whole body PET/CT imaging is highly desired for different
ages,sizes,and shapes.Therefore, in this study,organ absorbed doses were
evaluated for pediatric voxel models from 4 to 14 years old and compared with
those of ICRP phantoms.Monte Carlo calculation was performed to evaluate Svalue,
absorbed dose, and effective dose from 18F-FDG radiotracers and whole
body CT scan for different computational models, including 4- to 14-year-old
phantoms. The results showed that the S-value and, therefore, absorbed dose
of 18F-FDG strongly depended on the phantom anatomy.These variations were
justified by the distance between source and target organs.Moreover, on average,
the absorbed doses from whole body CT scans were 13.5 times lower than
those from 18F-FDG for all organs. According to the results, various anatomies
and ages should be considered for accurate dose evaluation.These data can be
used for specific risk assessment of the pediatric population in clinical nuclear
imaging. |