Abstract：
Circulating T-lymphocytes are used as \"natural biodosimeters\" for estimating radiation doses, since the frequency of chromosomal aberrations induced in them is proportional to the accumulated dose. Moreover, stable chromosomal aberrations (translocations) are detected years and decades after exposure. Internal incorporation of radionuclides often leads to non-uniform exposure, which resulted in difficulties in the application of retrospective biodosimetry using T-lymphocytes. Some properties of T-lymphocytes complicate retrospective biodosimetry in this case: (1) the thymic production of T-cells depends significantly on age, the maximum is observed in early childhood; (2) the \"lymphocyte-dosimeter\" accumulates changes (translocations) while circulating through the body. The objective of this paper is to describe the technical characteristics of the model of age dynamics and T-cell biokinetics and approaches to assessing the dose to circulating lymphocytes under various exposure scenarios. The model allows to quantify the fractions of T-lymphocytes that were formed before and after exposure. The model takes into account the time fractions that circulating lymphocytes spend in various lymphoid organs. Age-related thymic involution was also considered. The model predicts that after internal exposure to 90Sr, the doses to T-lymphocytes can differ significantly from the doses to the bone marrow and other tissues. For uniform external γ-exposure, and for internal exposure due to non-bone -seeking radionuclides (for example, 144Ce), predicted doses to T-lymphocytes are very close to bone marrow doses. The model allows to quantify the correction factors for FISH-based doses to obtain doses to organs and tissues.
摘要：
循环T淋巴细胞被用作“天然生物剂量计”，用于估计辐射剂量，因为它们引起的染色体畸变的频率与累积剂量成正比。此外，暴露后数年和数十年检测到稳定的染色体畸变（易位）。放射性核素的内部掺入通常会导致不均匀的暴露，这导致使用T淋巴细胞的回顾性生物剂量学应用困难。在这种情况下，T淋巴细胞的某些特性使回顾性生物剂量学复杂化：（1）T细胞的胸腺产生显着取决于年龄，在儿童早期观察到最大值；（2）“淋巴细胞剂量计”在体内循环时积累变化（易位）。本文的目的是描述年龄动力学和T细胞生物动力学模型的技术特征，以及在各种暴露情况下评估循环淋巴细胞剂量的方法。该模型允许量化暴露之前和之后形成的T淋巴细胞的分数。该模型考虑了循环淋巴细胞在各种淋巴器官中花费的时间分数。还考虑了与年龄相关的胸腺退化。该模型预测，在内部暴露于90Sr后，T淋巴细胞的剂量可能与骨髓和其他组织的剂量显着不同。对于均匀的外部γ曝光，以及由于非寻骨放射性核素而引起的内部暴露(例如，144Ce)，T淋巴细胞的预测剂量非常接近骨髓剂量。该模型允许量化基于FISH的剂量的校正因子,以获得对器官和组织的剂量。
