The development of the resolution enhanced Chinese Reference Adult Female voxel phantom and its application on organ dose calculation

• Main Authors: Yi Chun Tsai, 蔡宜君
• Other Authors: C. C. Lee
• Format: Others
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/60845309038717503089

碩士 === 長庚大學 === 醫學影像暨放射科學系 === 101 === The purpose of this study is to enhance resolution of Chinese reference adult female (CRAF) voxel phantom and to calculate its organ doses using Monte Carlo simulation. To calculate the organ dose, Monte Carlo method and voxel phantoms are often used to simulate the energy deposition in human body and the voxel size of phantom will influence the accuracy and precision of these dose calculations.In this study, axial resolutions of 56 organs in CRAF phantom were enhanced by using objective interpolation method. A new axial resolution voxel phantom was reconstructed and named CRAF66. Good neighbor method was implemented to solve the overlapping and defect voxels near organ boundaries on CRAF66. After CRAF66 phantom was ready, Monte Carlo code EGS4-VLSI was applied to calculate organ doses of CRAF and CRAF66 against external and internal photon /electron exposure. Fisher’s least significant difference (LSD) was used to evaluate if voxel sizes significantly affect the organ dose calculation. Results show that axial resolution of CRAF phantom was successfully enhanced from 1.98 mm in head and from 3.96 mm in body to 0.66 mm in CRAF66. The LSD results show that organ dose differences between CRAF66 and CRAF in vessel, bone and muscle are small but statistically significant against external photon/electron exposure. The organ dose differences between CRAF66 and CRAF in small source organs are small but statistics significant against internal photon exposure. We found out that the voxel sizes of phantom influence organ dose mostly and the organ doses difference between CRAF66 and CRAF are statistically significant in most source organs against internal electron exposure.