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Endo, Akira
Annals of the ICRP, 52(4), p.5 - 7, 2024/12
In its Publication 155, International Commission on Radiological Protection (ICRP) has developed data on the Specific Absorbed Fraction (SAF) for reference males and females at ages of newborn, 1 year, 5 years, 10 years, and 15 years. The SAF represents the fraction of energy emitted within a source region which is absorbed in a target region per mass of the target region and is essential for calculating absorbed doses in organs or tissues for internal exposure. By combining the data of Publication 155 with the SAF data for reference adult males and females already published as Publication 133, an SAF dataset for the calculation of age-dependent dose coefficients for members of the public for environmental intakes of radionuclides has been completed. This, together with revised biokinetic models and nuclear decay data, means that the key building blocks for calculating new dose coefficients are in place. The outcome will soon be available in a series of ICRP Publications of Dose Coefficients for Intakes of Radionuclides by Members of the Public.
Sato, Kaoru; Noguchi, Hiroshi; Saito, Kimiaki; Emoto, Yutaka*; Koga, Sukehiko*
Radiation Risk Assessment Workshop Proceedings, p.102 - 110, 2001/00
For calculating doses due to radioactivity taken in a body, Specific Absorbed Fractions (SAFs) are used. In recent years, more realistic phantoms called voxel (volume pixel) phantoms have been developed on the basis of CT or MRI images of actual persons. The voxel phantoms can accurately describe sizes, shapes and locations of organs, which would affect SAFs. We are now developing Japanese adult voxel phantoms for internal dosimetry by using CT images. Until now, CT scans for three healthy Japanese male volunteers were performed under supine or upright positions to study the effect of body size and position on SAFs. The height and weight of the middle size man is almost coincident with the averages for Japanese adult. So far the development of voxel phantom has been almost finished for the middle size man (voxel-phantom-MM). The voxel size is 0.980.98
1.0 mm
. It was found that even small size organs such as thyroid were realistically modeled. The result showed that voxel-phantom-MM had realistic structure which would enable us to calculate reliable SAFs