Moraleda M, Gómez-Ros J M
CIEMAT, Avd. Complutense 40, Madrid 28040, Spain
CIEMAT, Avd. Complutense 40, Madrid 28040, Spain.
Radiat Prot Dosimetry. 2016 Sep;170(1-4):364-8. doi: 10.1093/rpd/ncv509. Epub 2015 Dec 24.
At the CIEMAT whole-body counter, a low-energy germanium detector is used for the in vivo assessment of (131)I activity in thyroid, mainly for the individual monitoring programmes of workers. The detector is calibrated with a cylindrical neck phantom made of polymethyl methacrylate that mimics the neck of an adult, containing a vial with a radioactive solution. For an accurate activity assessment, it is necessary to perform the calibration of the detector with phantoms that closely reproduce the anatomy of a real person. Nevertheless, it is not affordable to count on a variety of physical phantoms covering the different anatomical characteristics that could be found over the whole population, including children. An alternative approach to face this situation is offered by the numerical calibration procedure based on Monte Carlo calculations in conjunction with realistic voxel phantoms. A series of computational voxel phantoms of different ages and dimensions have been used in this work to simulate an internal contamination of the thyroid and to estimate the response of the detector for measurements involving individuals whose anatomical characteristics differ from the reference adult man.
在CIEMAT全身计数器中，一个低能锗探测器用于体内评估甲状腺中的（131）I活度，主要用于工作人员的个人监测计划。该探测器用由聚甲基丙烯酸甲酯制成的圆柱形颈部体模进行校准，该体模模拟成年人的颈部，包含一个装有放射性溶液的小瓶。为了进行准确的活度评估，有必要使用能紧密再现真实人体解剖结构的体模对探测器进行校准。然而，指望有各种涵盖整个人口中可能发现的不同解剖特征（包括儿童）的物理体模是不划算的。基于蒙特卡罗计算并结合逼真的体素体模的数值校准程序为应对这种情况提供了一种替代方法。在这项工作中，使用了一系列不同年龄和尺寸的计算体素体模来模拟甲状腺的内部污染，并估计探测器对涉及解剖特征与参考成年男性不同的个体的测量的响应。
