Idaho State University, Nuclear Engineering and Health Physics, P.O. Box 8106, Pocatello ID 83209, USA.
Health Phys. 2013 Jan;104(1):51-6. doi: 10.1097/HP.0b013e318261f1f6.
A new leg voxel model in two different positions (straight and bent) has been developed for in vivo measurement calibration purposes. This voxel phantom is a representation of a human leg that may provide a substantial enhancement to Monte Carlo modeling because it more accurately models different geometric leg positions and the non-uniform distribution of Am throughout the leg bones instead of assuming a one-position geometry and a uniform distribution of radionuclides. This was accomplished by performing a radiochemical analysis on small sections of the leg bones from the U.S. Transuranium and Uranium Registries (USTUR) case 0846. USTUR case 0846 represents an individual who was repeatedly contaminated by Am via chronic inhalation. To construct the voxel model, high resolution (2 mm) computed tomography (CT) images of the USTUR case 0846 leg were obtained in different positions. Thirty-six (36) objects (universes) were segmented manually from the CT images using 3D-Doctor software. Bones were divided into 30 small sections with an assigned weight exactly equal to the weight of bone sections obtained from radiochemical analysis of the USTUR case 0846 leg. The segmented images were then converted into a boundary file, and the Human Monitoring Laboratory (HML) voxelizer was used to convert the boundary file into the leg voxel phantom. Excluding the surrounding air regions, the straight leg phantom consists of 592,023 voxels, while the bent leg consists of 337,567 voxels. The resulting leg voxel model is now ready for use as an MCNPX input file to simulate in vivo measurement of bone-seeking radionuclides.
为了进行体内测量校准目的，已经开发出了两种不同位置（直腿和弯腿）的新型腿部体素模型。这种体素模型是人体腿部的一种表示，它可以为蒙特卡罗建模提供实质性的增强，因为它更准确地模拟了不同的腿部几何位置和 Am 在腿部骨骼中的不均匀分布，而不是假设一个位置的几何形状和放射性核素的均匀分布。这是通过对来自美国超铀和铀登记册（USTUR）病例 0846 的腿部小部分进行放射性化学分析来实现的。USTUR 病例 0846 代表了一个通过慢性吸入反复受到 Am 污染的个体。为了构建体素模型，从 USTUR 病例 0846 的腿部获得了不同位置的高分辨率（2 毫米）计算机断层扫描（CT）图像。使用 3D-Doctor 软件，从 CT 图像中手动分割了 36 个（36 个）物体（宇宙）。骨头被分为 30 个小部分，每个部分的重量与从 USTUR 病例 0846 腿部放射性化学分析中获得的骨部分重量完全相等。然后将分割的图像转换为边界文件，并且使用人体监测实验室（HML）体素化器将边界文件转换为腿部体素模型。排除周围空气区域，直腿模型由 592,023 个体素组成，而弯腿模型由 337,567 个体素组成。生成的腿部体素模型现在已准备好用作 MCNPX 输入文件，以模拟对骨靶向放射性核素的体内测量。
