Proportion-corrected scaled voxel models for Japanese children and their application to the numerical dosimetry of specific absorption rate for frequencies from 30 MHz to 3 GHz.
The development of high-resolution anatomical voxel models of children is difficult given, inter alia, the ethical limitations on subjecting children to medical imaging. We instead used an existing voxel model of a Japanese adult and three-dimensional deformation to develop three voxel models that match the average body proportions of Japanese children at 3, 5 and 7 years old. The adult model was deformed to match the proportions of a child by using the measured dimensions of various body parts of children at 3, 5 and 7 years old and a free-form deformation technique. The three developed models represent average-size Japanese children of the respective ages. They consist of cubic voxels (2 mm on each side) and are segmented into 51 tissues and organs. We calculated the whole-body-averaged specific absorption rates (WBA-SARs) and tissue-averaged SARs for the child models for exposures to plane waves from 30 MHz to 3 GHz; these results were then compared with those for scaled down adult models. We also determined the incident electric-field strength required to produce the exposure equivalent to the ICNIRP basic restriction for general public exposure, i.e., a WBA-SAR of 0.08 W kg(-1).
Nagaoka
Tomoaki
T
National Institute of Information and Communications Technology, 4-2-1 Nukuikitamachi, Koganei, Tokyo 184-8795, Japan. nagaoka@nict.go.jp
Kunieda
Etsuo
E
Watanabe
Soichi
S
D001824:Body Constitution; D002648:Child; D002675:Child, Preschool; D004574:Electromagnetic Fields; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007564:Japan; D008953:Models, Anatomic; D011829:Radiation Dosage; D011835:Radiation Protection