We report the generation of dose point kernels for clinically-relevant radionuclide beta decays and monoenergetic electrons in various tissues to understand the impact of tissue type on dose point kernels. Currently available voxel-wise dosimetry approaches using dose point kernels ignore tissue composition and density heterogeneities. Therefore, the study on the impact of tissue type on dose point kernels is warranted. Simulations were performed using the GATE Monte Carlo toolkit, which encapsulates GEANT4 libraries. Dose point kernels were simulated in phantoms of water, compact bone, lung, adipose tissue, blood and red marrow for radionuclides 90Y, 188Re, 32P, 89Sr, 186Re, 153Sm and 177Lu and monoenergetic electrons (0.015-10 MeV). All simulations were performed by assuming an isotropic point source of electrons at the center of a homogeneous spherical phantom. Tissue-specific differences between kernels were investigated by normalizing kernels for effective pathlength. Transport of 20 million particles was found to provide sufficient statistical precision in all simulated kernels. The simulated dose point kernels demonstrate excellent agreement with other Monte Carlo packages. Deviation from kernels reported in the literature did not exceed a 10% global difference, which is consistent with the variability among published results. There are no significant differences between the dose point kernel in water and kernels in other tissues that have been scaled to account for density; however, tissue density predictably demonstrated itself to be a significant variable in dose point kernel distribution.

中文翻译：

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组织类型和密度对剂量点核的影响，具体用于患者特定的体素-明智剂量测定：蒙特卡洛研究。

我们报告了在各种组织中与临床相关的放射性核素β衰变和单能电子的剂量点内核的生成，以了解组织类型对剂量点内核的影响。当前使用剂量点内核的体素剂量方法忽略了组织组成和密度异质性。因此，有必要对组织类型对剂量点谷粒的影响进行研究。使用封装GEANT4库的GATE Monte Carlo工具包进行了仿真。在水，紧密的骨骼，肺，脂肪组织，血液和红骨髓的体模中模拟了放射性核素90Y，188Re，32P，89Sr，186Re，153Sm和177Lu和单能电子（0.015-10 MeV）的剂量点内核。所有模拟都是通过假设均质球形幻影中心的电子各向同性点源来进行的。通过标准化内核的有效路径长度来研究内核之间的组织特异性差异。发现在所有模拟内核中，2000万个粒子的传输都提供了足够的统计精度。模拟的剂量点内核证明与其他Monte Carlo软件包极佳的一致性。与文献报道的籽粒偏差不超过10％的总体差异，这与已发表结果之间的差异一致。水中的剂量点籽粒与其他组织的籽粒中的剂量点籽粒之间没有明显差异，这些点已按比例缩放以解决密度问题。然而，