基于可视中国数字人体素模型的比吸收分数计算

Calculation of Specific Absorbed Fraction Based on VCH Voxel Model

目的开展器官比吸收分数的计算研究,以定量计算人体的内照射剂量。方法在高分辨可视中国人三维解剖结构数据集基础上,对原始图片进行分割、标识、赋值和低抽样,构建了基于体素数据的内辐射模型。采用基于蒙特卡洛方法的MCNPX软件,模拟了光子在人体器官组织间的传输过程,得到了各能量下源器官对目标器官的比吸收分数,并与中国数学模型的计算结果进行了比较。结果两组数据在趋势上具有相似性,说明了计算方法的正确性;体素模型的计算结果较数学模型大,主要源自模型间器官质量和器官距离的不同;数学模型中部分结果具有明显差异性,说明其计算结果可能不准确。结论基于中国数字人体素模型计算的比吸收分数,提供了更为准确和可靠的数据。

Objective To quantitatively calculate the internal radiation dose of the human body by studying the organ specific absorbed fractions（SAF）.Methods The voxel internal radiation model was developed with segmenting,labeling,assigning and sampling the original images,based on the three-dimensional anatomical structure datasets from high resolution Visible Chinese Human（VCH）.Using MCNPX Monte Carlo code,the transport procedure of photon were simulated,and then the SAFs at various energies were obtained and compared with those from the Chinese mathematical model.Results The method was proved correct by the similar trend in the two sets of data.SAFs from the voxel model were higher than those from the mathematical model due to the discrepancies of organ mass and inter-organ distance.Part of the SAFs from the mathematical model were found quite different,which might lead to inaccurate results.Conclusion The SAF from the VCH voxel model may provide more accurate and reliable data.