title: Organ dose conversion coefficients for external photon irradiation using the Chinese voxel phantom (CVP).
abstract: A set of conversion coefficients from kerma free-in-air to the organ absorbed dose are presented for external monoenergetic photon beams from 10 keV to 10 MeV based on a whole-body, Chinese adult male voxel phantom. This computational phantom, called the Chinese voxel phantom (CVP), including totally 23 organs, was developed from magnetic resonance imaging of a young healthy Chinese man at a resolution of 2 x 2 mm. Compared with the ICRP Reference Man, more than half of the organs or tissues in the CVP show mass differences of more than 20. Monte Carlo simulations with MCNP code were carried out to calculate the organ dose conversion coefficients. Irradiation conditions include anterior-posterior, posterior-anterior (PA), right-lateral, left-lateral, rotational and isotropic geometries. Organ dose conversion coefficients from this study are compared with the data from the Asian voxel phantoms Visible Chinese Human and KORMAN. These data sets agree with each other within 10% for photon energy >5 MeV. However, discrepancies of 34-63% were observed for organs of the alimentary tract, such as the oesophagus and stomach, those of the urinary system, such as the bladder wall and thyroid, especially at low photon energy range and PA geometry. These results suggest that the anatomical variation within the Chinese population, as represented by these adult male voxel phantoms, can lead to uncertainties when a standard phantom is used for the entire population.
authors.affiliation: Key Laboratory of Particle and Radiation Imaging, Tsinghua University, Ministry of Education, Beijing 100084, China.
authors.forename: Junli
authors.initials: J
authors.lastname: Li
authors.forename: Rui
authors.initials: R
authors.lastname: Qiu
authors.forename: Zhan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Liye
authors.initials: L
authors.lastname: Liu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zeng
authors.forename: Lei
authors.initials: L
authors.lastname: Bi
authors.forename: Wenqian
authors.initials: W
authors.lastname: Li
mesh_terms: D044466:Asian People; D001822:Body Burden; D003198:Computer Simulation; D006801:Humans; D008954:Models, Biological; D009928:Organ Specificity; D017785:Photons; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D012542:Scattering, Radiation