Baechler S, Stritt N, Bochud F O
Institute of Radiation Physics, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
Radiat Prot Dosimetry. 2011 Mar;144(1-4):464-7. doi: 10.1093/rpd/ncq350. Epub 2010 Nov 15.
Monitoring of internal exposure for nuclear medicine workers requires frequent measurements due to the short physical half-lives of most radionuclides used in this field. The aim of this study was to develop screening measurements performed at the workplace by local staff using standard laboratory instrumentation, to detect whether potential intake has occurred. Such measurements do not enable to determine the committed effective dose, but are adequate to verify that a given threshold is not exceeded. For radioiodine, i.e. (123)I, (124)I, (125)I and (131)I, a calibrated surface contamination monitor is placed in front of the thyroid to detect whether the activity threshold has been exceeded. For radionuclides with very short physical half-lives (≤ 6 h), such as (99m)Tc and those used in positron emission tomography imaging, i.e. (11)C, (15)O, (18)F and (68)Ga, screening procedures consist in performing daily measurements of the ambient dose rate in front of the abdomen. Other gamma emitters used for imaging, i.e. (67)Ga, (111)In and (201)Tl, are measured with a scintillation detector located in front of the thorax. For pure beta emitters, i.e. (90)Y and (169)Er, as well as beta emitters with low-intensity gamma rays, i.e. (153)Sm, (177)Lu, (186)Re and (188)Re, the procedure consists in measuring hand contamination immediately after use. In Switzerland, screening procedures have been adopted by most nuclear medicine services since such measurements enable an acceptable monitoring while taking into account practical and economic considerations.
由于核医学领域使用的大多数放射性核素物理半衰期较短，因此需要对核医学工作者进行频繁的体内照射监测。本研究的目的是开发由当地工作人员在工作场所使用标准实验室仪器进行的筛查测量方法，以检测是否发生了潜在摄入。此类测量无法确定待积有效剂量，但足以验证未超过给定阈值。对于放射性碘，即（123）I、（124）I、（125）I和（131）I，将校准过的表面污染监测仪置于甲状腺前方，以检测是否超过了活度阈值。对于物理半衰期非常短（≤6小时）的放射性核素，如（99m）Tc以及用于正电子发射断层显像的核素，即（11）C、（15）O、（18）F和（68）Ga，筛查程序包括每天测量腹部前方的环境剂量率。用于显像的其他γ发射体，即（67）Ga、（111）In和（201）Tl，用置于胸部前方的闪烁探测器进行测量。对于纯β发射体，即（90）Y和（169）Er，以及伴有低强度γ射线的β发射体，即（153）Sm、（177）Lu、（186）Re和（188）Re，程序是在使用后立即测量手部污染情况。在瑞士，大多数核医学服务机构都采用了筛查程序，因为此类测量在考虑实际和经济因素的同时能够实现可接受的监测。
