Japanese adult male voxel phantom constructed on the basis of CT images

Sato, Kaoru   ; Noguchi, Hiroshi; Emoto, Yutaka*; Koga, Sukehiko*; Saito, Kimiaki  

A Japanese adult male voxel (volume pixel) phantom (hereinafter referred to as the JM phantom) was constructed on the basis of CT images of a healthy Japanese adult male volunteer. Body characteristics of the JM phantom were compared with those of a voxelized MIRD5 type phantom and a Japanese adult male voxel phantom which was previously developed. The voxel size of the JM phantom is 0.980.981 mm. The shapes of organs of the JM phantom, even for small or complicated organs, such as thyroid and stomach, are more realistically reproduced as compared with the previous Japanese voxel phantom (voxel size: 0.980.9810 mm). Photon self-absorbed fractions for brain, kidneys, spleen, pancreas, thyroid and urinary bladder wall of JM were evaluated and were compared with those of the other phantoms. In consequence, it was suggested that the mass, shape and thickness of organs are important factors for the determination of self-absorbed fractions.