^(41)Ca的AMS测量方法及在生物医学领域的应用  

Research Progress of AMS Measurement of ^(41)Ca and Its Biomedical Applications

作　　者：毕艳婷 付云翀[2,3] BI Yanting;FU Yunchong(Xi’an Institute for Innovative Earth Environment Research,Xi’an 710061,China;State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,China;Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application,Xi’an Accelerator Mass Spectrometry Center,Xi’an 710061,China)

机构地区：[1]西安地球环境创新研究院,西安710061 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710061 [3]西安加速器质谱中心陕西省加速器质谱技术及应用重点实验室,西安710061

出　　处：《同位素》2024年第1期64-76,共13页Journal of Isotopes

基　　金：中国科学院战略性先导科技专项(B类)“亚太多尺度气候环境变化动力学”(XDB40000000)。

摘　　要：钙(Ca)的长寿命放射性核素^(41)Ca是理想且安全的生物示踪剂,在生物医学领域具有重要价值,但其发展一直受制于测量技术。传统衰变计数法测量效率极低、样品需求量高且耗费时间长,无法有效开展^(41)Ca分析;普通质谱方法很难剔除同量异位素41K和分子碎片的干扰,难以获得理想的探测限。而加速器质谱法(AMS)测定^(41)Ca具有样品用量小(mg量级)、测量时间短(约1 h)、检测灵敏度高(^(41)Ca/^(40)Ca丰度灵敏度最低可至10^(-15))等优点,是目前分析^(41)Ca最常用的方法。AMS测量的关键是如何有效剔除或分离同量异位素41K。本研究从样品形式的选择和仪器技术两方面综述了^(41)Ca的AMS测量方法发展进程。一方面,使用CaH_(2)或CaF_(2)作为主要样品形式目前可以有效抑制41K的干扰。CaF_(2)制备流程更简单,存储更方便,束流引出阶段对同量异位素41K的抑制在4个量级左右,满足添加^(41)Ca为示踪剂的生物医学样品的分析要求。另一方面,随着AMS逐渐小型化,^(41)Ca-AMS测量技术也在不断改进。对比不同能量下AMS分析^(41)Ca的特点、优势和局限性,其中:高能量大型(≥5 MV)AMS对41K有足够的辨别能力,测量灵敏度一般在10^(-14)~10^(-15),但由于成本和仪器运行专业性过高的要求,使其应用不够广泛;低能量小型(≤3 MV)AMS应用最为广泛,虽然只能将^(41)Ca和41K部分分离,但可以通过dE/dx、ΔTOF和ISA等方法对^(41)Ca实现直接测量,测量灵敏度在10^(-12)~10^(-13)或有望更低;而更低能量的紧凑型(≤1 MV)AMS无法在低能量情况下将^(41)Ca和41K分离,只能通过39K校正的间接方法实现对^(41)Ca的测量,测量灵敏度一般为10^(-11)~10^(-12)之间。在此基础上,本研究介绍了基于^(41)Ca-AMS分析技术在生物医学领域中的应用。^(41)Ca示踪技术是目前探究生物体骨钙代谢的重要手段,在评估人类骨骼健康、监测骨重塑动态和建立人类钙平衡�^(41)Ca,a long-lived radioactive isotope of calcium(Ca),is considered as an ideal biological tracer,and has been widely used in the biomedical field.But its development has been limited by measurement techniques.The traditional decay counting measurement techniques cannot be used for ^(41)Ca analysis due to its low measurement efficiency,high sample requirement and long time consuming.It is also difficult to eliminate interferences from the stable 41 K isobar and molecular species so as to obtain the ideal detection limit for conventional mass spectrometric measurements.However,accelerator mass spectrometry(AMS)is the most commonly analysis method for ^(41)Ca,which has the advantages of smaller sample size(mg magnitude),shorter measurement time(~1 h)and higher detection sensitivity(^(41)Ca/^(40)Ca abundance sensitivity can be 10^(-15)).The key of ^(41)Ca AMS measurement is how to eliminate or separate the isobar 41 K.In this paper,the development of AMS measurement methods for ^(41)Ca was reviewed from the selection of sample form and instrument technology.On the one hand,the use of either CaH_(2) or CaF_(2) can effectively inhibit the interferences from the stable 41 K isobar.In contrast,the preparation process of CaF_(2) is simpler and more convenient to store.In the beam extraction stage,the suppression of the isobar 41 K is about 4 orders of magnitude,which satisfies the measurement requirements of biological samples with ^(41)Ca as tracer.On the other hand,^(41)Ca-AMS measurement technology has improved as AMS has been miniaturized.We compared the characteristics,advantages and limitations of different energy AMS for ^(41)Ca analysis.The large(≥5 MV)AMS has sufficient ability to discriminate 41 K,and the measurement sensitivity is generally 10^(-14) to 10^(-15).But it is not widely used due to the high cost and professional requirements of instrument operation.For the small(≤3 MV)AMS that are the most widely used,the d E/d x,ΔTOF and ISA method can be used to partially separate ^(41)Ca from 41 K.The mea

关 键 词：^(41)Ca 加速器质谱 测量方法 生物医学 

分 类 号：TL99[核科学技术—核技术及应用] O657[理学—分析化学]