Department of Nuclear Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791, Korea.
Phys Med Biol. 2011 May 21;56(10):3137-61. doi: 10.1088/0031-9155/56/10/016. Epub 2011 Apr 27.
Even though the hybrid phantom embodies both the anatomic reality of voxel phantoms and the deformability of stylized phantoms, it must be voxelized to be used in a Monte Carlo code for dose calculation or some imaging simulation, which incurs the inherent limitations of voxel phantoms. In the present study, a voxel phantom named VKH-Man (Visible Korean Human-Man), was converted to a polygon-surface phantom (PSRK-Man, Polygon-Surface Reference Korean-Man), which was then adjusted to the Reference Korean data. Subsequently, the PSRK-Man polygon phantom was directly, without any voxelization process, implemented in the Geant4 Monte Carlo code for dose calculations. The calculated dose values and computation time were then compared with those of HDRK-Man (High Definition Reference Korean-Man), a corresponding voxel phantom adjusted to the same Reference Korean data from the same VKH-Man voxel phantom. Our results showed that the calculated dose values of the PSRK-Man surface phantom agreed well with those of the HDRK-Man voxel phantom. The calculation speed for the PSRK-Man polygon phantom though was 70-150 times slower than that of the HDRK-Man voxel phantom; that speed, however, could be acceptable in some applications, in that direct use of the surface phantom PSRK-Man in Geant4 does not require a separate voxelization process. Computing speed can be enhanced, in future, either by optimizing the Monte Carlo transport kernel for the polygon surfaces or by using modern computing technologies such as grid computing and general-purpose computing on graphics processing units programming.
尽管混合体模结合了体素体模的解剖学真实性和风格化体模的可变形性，但它必须进行体素化才能在用于剂量计算或某些成像模拟的蒙特卡罗代码中使用，这会带来体素体模固有的局限性。在本研究中，我们将一个名为 VKH-Man（可见韩国人-男性）的体素体模转换为多边形表面体模（PSRK-Man，多边形表面参考韩国人-男性），然后对其进行调整以符合参考韩国人数据。随后，我们直接将 PSRK-Man 多边形体模而无需任何体素化过程，应用于 Geant4 蒙特卡罗代码进行剂量计算。然后比较计算得到的剂量值和计算时间与 HDRK-Man（高分辨率参考韩国人-男性）的结果，HDRK-Man 是一个经过调整以符合相同参考韩国人数据的体素体模。我们的结果表明，PSRK-Man 表面体模的计算剂量值与 HDRK-Man 体素体模的计算剂量值吻合良好。虽然 PSRK-Man 多边形体模的计算速度比 HDRK-Man 体素体模慢 70-150 倍，但在某些应用中，直接在 Geant4 中使用表面体模 PSRK-Man 是可以接受的，因为它不需要单独的体素化过程。未来，可以通过优化多边形表面的蒙特卡罗输运核或者使用现代计算技术，如网格计算和图形处理单元编程的通用计算来提高计算速度。
