Analysis of Organ Doses from Computed Tomography (CT) Examination by the Radiation Transport Calculation to Develop the Dosimetry System, WAZA-ARI

A new dosimetry system, named WAZA-ARI, is being developed to assess organ doses of a patient in a Computed Tomography (CT) examination.A Japanese adult male voxel phantom (JM phantom) is applied to derive the basic data for dose assessment in WAZA-ARI.The JM phantom defines outer and inner configurations of the human body more precisely than mathematical human models, such as the MIRD-type phantom.The radiation transport in CT examination was simulated with the Particle and Heavy Ion Transport code System, PHITS.A subroutine in PHITS described a source model to simulate emission of photons in a CT machine.This study clarified the relationships between the organ doses and X-ray scanning on a human body with some geometrical conditions.