RELATIVE BIOLOGICAL EFFECTIVENESS OF ALPHA-PARTICLE EMITTERS IN-VIVO AT LOW-DOSES
RELATIVE BIOLOGICAL EFFECTIVENESS OF ALPHA-PARTICLE EMITTERS IN-VIVO AT LOW-DOSES
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DOI：
10.2307/3578710
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发表时间：
1994-03-01
影响因子：
3.4
通讯作者：
RAO, DV
中科院分区：
文献类型：
--
作者：
HOWELL, RW;AZURE, MT;RAO, DV
发射α粒子的放射性核素的治疗潜力及其相关的健康危害引起了相当大的关注。Ra-224子体Pb-212和Bi-212由于它们的辐射性质（涉及在它们衰变成稳定的Pb-208时发射α和β粒子）而被提议作为放射免疫疗法的候选物。本文以小鼠睾丸为实验模型，以睾丸精头存活为生物学终点，考察了Pb-212及其子体的放射毒性。当Pb-212与其子体Bi-212、Po-212和Tl-208平衡时，直接给予睾丸，达到37%存活率（D-37）所需的剂量为0.143 +/- 0.014戈伊，与急性外部120 kVp X射线的D-37相比，混合辐射野的相应RBE为4.7。这个数据，结合我们早期对Po-210的结果，被用来获得由组织结合放射性核素发射的粒子的RBE-LET关系：RBE（α）= 4.8 - 6.1 x 10（-2）LET + 1.0 x 10（-3）LET（2）。类似地，RBE对α粒子能量E（α）的依赖关系由RBE，= 22 E（α）（-0.73）给出。这些关系，在体内实验数据的基础上，可能是有价值的预测α粒子发射体的生物效应。
The therapeutic potential of radionuclides that emit alpha particles, as well as their associated health hazards, have attracted considerable attention. The Ra-224 daughters Pb-212 and Bi-212, by virtue of their radiation properties which involve emission of a and beta particles in their decay to stable Pb-208, have been proposed as candidates for radioimmunotherapy. Using mouse testes as the experimental model and testicular spermhead survival as the biological end point, the present work examines the radiotoxicity of Pb-212 and its daughters. When Pb-212, in equilibrium with its daughters Bi-212, Po-212 and Tl-208, was administered directly into the testis, the dose required to achieve 37% survival (D-37) was 0.143 +/- 0.014 Gy and the corresponding RBE of the mixed radiation field was 4.7 when compared to the D-37 for acute external 120 kVp X rays. This datum, in conjunction with our earlier results for Po-210, was used to obtain an RBE-LET relationship for a particles emitted by tissue-incorporated radionuclides: RBE(alpha) = 4.8 - 6.1 x 10(-2) LET + 1.0 x 10(-3) LET(2). Similarly, the dependence of RBE on alpha-particle energy E(alpha) was given by RBE, = 22 E(alpha)(-0.73). These relationships, based on in vivo experimental data, may be valuable in predicting biological effects of alpha-particle emitters.