Ahlgren L, Albertsson M, Areberg J, Kadar L, Lindén M, Mattsson S, McNeill F
Department of Radiation Physics, Malmö University Hospital, Sweden.
Acta Oncol. 1999;38(4):431-7. doi: 10.1080/028418699431951.
A hospital-based facility for in vivo prompt gamma neutron activation analysis of nitrogen for body protein determination is described. The patient is laid on a movable couch and is scanned with a vertically collimated neutron beam from a 252Cf neutron source (the amount of Cf varying from 120 to 40 microg due to the physical decay) positioned below the patient. Four large NaI(Tl) detectors are used to measure the 10.8 MeV gamma-rays from nitrogen. To check the long-term stability of the system, a solid phantom simulating the geometry of the adult human trunk, having similar elemental composition as tissue, was constructed. Repeated phantom measurements over 6 months gave a reproducibility in nitrogen determination of 2.9% (1 SD). Duplicate patient measurements carried out within a week showed a reproducibility of 5% (1 SD). A calibration method for absolute protein measurements in patients is presented. Patients are normally measured for 40 min; giving a mean whole-body equivalent dose of 0.25 mSv. Results from measurements on 13 cancer patients are presented.
描述了一种基于医院的用于体内快速伽马中子活化分析氮以测定人体蛋白质的设施。患者躺在可移动的病床上，由位于患者下方的252Cf中子源发出的垂直准直中子束进行扫描（由于物理衰变，Cf的量从120微克变化到40微克）。使用四个大型碘化钠（铊）探测器来测量来自氮的10.8兆电子伏伽马射线。为检查系统的长期稳定性，构建了一个模拟成年人体躯干几何形状、元素组成与组织相似的固体模型。在6个月内对模型进行的重复测量在氮测定方面的重现性为2.9%（1标准差）。在一周内对患者进行的重复测量显示重现性为5%（1标准差）。提出了一种用于患者绝对蛋白质测量的校准方法。患者通常测量40分钟；全身平均等效剂量为0.25毫希沃特。给出了13名癌症患者的测量结果。
