Helmholtz Zentrum München, German Research Center for Environmental Health, Department of Medical Radiation Physics and Diagnostics, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
Sci Total Environ. 2011 Sep 1;409(19):3701-10. doi: 10.1016/j.scitotenv.2011.06.031. Epub 2011 Jul 2.
Biokinetic models describing the uptake, distribution and excretion of trace elements are an essential tool in nutrition, toxicology, or internal dosimetry of radionuclides. Zirconium, especially its radioisotope (95)Zr, is relevant to radiation protection due to its production in uranium fission and neutron activation of nuclear fuel cladding material. We present a comprehensive set of human data from a tracer study with stable isotopes of zirconium. The data are used to refine a biokinetic model of zirconium. Six female and seven male healthy adult volunteers participated in the study. It includes 16 complete double tracer investigations with oral ingestion and intravenous injection, and seven supplemental investigations. Tracer concentrations were measured in blood plasma and urine collected up to 100 d after tracer administration. The four data sets (two chemical tracer forms in plasma and urine) each encompass 105-240 measured concentration values above detection limits. Total fractional absorption of ingested zirconium was found to be 0.001 for zirconium in citrate-buffered drinking solution and 0.007 for zirconium oxalate solution. Biokinetic models were developed based on the linear first-order kinetic compartmental model approach used by the International Commission on Radiological Protection (ICRP). The main differences of the optimized systemic model of zirconium to the current ICRP model are (1) recycling into the transfer compartment made necessary by the observed tracer clearance from plasma, (2) different parameters related to fractional absorption for each form of the ingested tracer, and (3) a physiologically based excretion pathway to urine. The study considerably expands the knowledge on the biokinetics of zirconium, which was until now dominated by data from animal studies. The proposed systemic model improves the existing ICRP model, yet is based on the same principles and fits well into the ICRP radiation protection approach.
描述微量元素摄取、分布和排泄的生物动力学模型是营养、毒理学或放射性核素内剂量学的重要工具。锆，特别是其放射性同位素（95）Zr，由于其在铀裂变和核燃料包壳材料的中子活化中的产生，与辐射防护有关。我们提出了一套来自稳定同位素锆示踪研究的综合人体数据。这些数据用于改进锆的生物动力学模型。六名女性和七名男性健康成年志愿者参加了这项研究。它包括 16 次完整的双示踪剂口服和静脉注射研究，以及 7 次补充研究。在示踪剂给药后长达 100 天采集血血浆和尿液以测量示踪剂浓度。四个数据集（血浆和尿液中的两种化学示踪剂形式）每个都包含超过检测限的 105-240 个测量浓度值。发现柠檬酸缓冲饮用溶液中锆的总摄入锆的分数吸收为 0.001，而草酸锆溶液中为 0.007。生物动力学模型是基于国际辐射防护委员会（ICRP）使用的线性一阶动力学房室模型方法开发的。优化的锆系统模型与当前 ICRP 模型的主要区别在于：（1）观察到从血浆清除示踪剂后需要进行再循环进入转移室；（2）与摄入示踪剂的每种形式的分数吸收相关的不同参数；（3）建立基于生理学的排泄途径到尿液。这项研究大大扩展了对锆生物动力学的认识，直到现在，这一领域主要由动物研究的数据主导。所提出的系统模型改进了现有的 ICRP 模型，但基于相同的原则，并且很好地适应了 ICRP 的辐射防护方法。
