Stephan G, Kampen W U, Nosske D, Roos H
Department for Radiation Protection and Health, Federal Office for Radiation Protection, Ingolstaedter Landstrasse 1, 85764 Oberschleissheim, Germany.
Radiat Environ Biophys. 2005 May;44(1):23-8. doi: 10.1007/s00411-005-0275-x. Epub 2005 Apr 8.
The aim of this study was to investigate the in vivo frequency of chromosomal aberrations (primarily dicentric chromosomes and chromatid breaks) potentially induced by (224)Ra alpha-radiation in peripheral lymphocytes. The study was designed to serve as a cytogenetic analysis along with the therapeutic procedure of ankylosing spondylitis patients who were undergoing a treatment with (224)Ra-chloride. The total administered activity was 10 MBq, and the treatment followed a schedule of 10 i.v. injections per week, each with a dose of 1 MBq of (224)Ra. The calculation of absorbed doses delivered to the blood used the models suggested by the ICRP and yielded a value of 4.7 mGy/MBq. The frequency of chromosomal aberrations observed during the course of therapy was related to the blood dose. The frequency of dicentric chromosomes induced in vivo was found to agree well with the corresponding value of dicentrics induced in vitro. However--given that peripheral lymphocytes are in the cell cycle's G(0) stage--an unexpected increase with dose in the yield of chromatid breaks was observed, with about 95% of them occurring in cells without any other chromosome-type aberrations. Reasons for the production of chromatid breaks are discussed.
本研究的目的是调查²²⁴Raα辐射在外周血淋巴细胞中潜在诱导的染色体畸变（主要是双着丝粒染色体和染色单体断裂）的体内频率。该研究旨在作为强直性脊柱炎患者接受氯化²²⁴Ra治疗的细胞遗传学分析及治疗程序的一部分。总给药活度为10 MBq，治疗方案为每周静脉注射10次，每次剂量为1 MBq的²²⁴Ra。输送到血液的吸收剂量计算采用了国际辐射防护委员会（ICRP）建议的模型，得出的值为4.7 mGy/MBq。治疗过程中观察到的染色体畸变频率与血液剂量相关。发现体内诱导的双着丝粒染色体频率与体外诱导的双着丝粒相应值非常吻合。然而，鉴于外周血淋巴细胞处于细胞周期的G₀期，观察到染色单体断裂产率随剂量意外增加，其中约95%发生在没有任何其他染色体类型畸变的细胞中。本文讨论了产生染色单体断裂的原因。
