Akabani G, Poston J W, Bolch W E
Nuclear Engineering Department, Texas A & M University, College Station 77843.
J Nucl Med. 1991 May;32(5):835-9.
Energy deposition patterns are dependent upon the size and geometry of the source region, distribution of radioactive material, types of radiations and energies emitted by the radionuclide, as well as interfaces between different materials which may exist within the region. Commonly, in absorbed dose calculations for internally deposited beta-emitting radionuclides, it is assumed that the absorbed fraction of energy for the mean beta energy is a sufficient representation of the beta spectrum. The accuracy of this assumption was tested by comparing absorbed fractions calculated using actual beta spectral energies with those obtained using the mean beta energy for several radionuclides commonly used in nuclear medicine. A sphere composed of tissue was chosen as the preferred geometry. Spheres of 0.1, 0.5, 1.0, and 2.0 cm radius were used, and absorbed fractions were calculated as a function of surface-to-volume ratios. This allows the assessment of absorbed fraction in spheres where there is a uniform distribution of a radionuclide.
能量沉积模式取决于源区域的大小和几何形状、放射性物质的分布、放射性核素发射的辐射类型和能量，以及该区域内可能存在的不同材料之间的界面。通常，在内部沉积的发射β射线的放射性核素的吸收剂量计算中，假定平均β能量的能量吸收分数足以代表β能谱。通过比较使用实际β能谱能量计算的吸收分数与使用核医学中常用的几种放射性核素的平均β能量获得的吸收分数，对该假设的准确性进行了测试。选择由组织组成的球体作为首选几何形状。使用半径为0.1、0.5、1.0和2.0厘米的球体，并根据表面积与体积比计算吸收分数。这允许评估放射性核素均匀分布的球体中的吸收分数。
