Beddoe A H, Zuidmeer H, Hill G L
Phys Med Biol. 1984 Apr;29(4):371-83. doi: 10.1088/0031-9155/29/4/007.
The quantitative assessment of the nutritionally-important components of body composition (protein, water and fat) provides a basic tool for research into the metabolic and nutritional problems of critically ill patients requiring intensive care. The construction and calibration of a facility that provides bilateral irradiation of patients with neutrons from two 281 GBq 238Pu-Be sources is described. Patients are scanned over a 36 min period, and composite prompt gamma-spectra are collected from two 5 in X 4 in NaI(Tl) detectors, placed on either side of the patient, using a conventional spectroscopy analysis system. A ratio of nitrogen to hydrogen counts corrected for body habitus and background is derived, from which protein can be estimated. This technique, combined with the measurement of water by tritium dilution, enables protein, water and fat to be estimated with precisions of 4.2%, 1.5% and 6.3% respectively, for a total dose equivalent (neutrons and tritium betas) of less than 0.5 mSv per examination.
对身体成分中具有营养重要性的成分（蛋白质、水和脂肪）进行定量评估，为研究需要重症监护的危重病患者的代谢和营养问题提供了一种基本工具。本文描述了一种利用两个281 GBq的²³⁸Pu-Be源对患者进行双侧中子辐照的设备的构建和校准。患者在36分钟内接受扫描，并使用传统光谱分析系统，从放置在患者两侧的两个5英寸×4英寸的碘化钠（铊）探测器收集复合瞬发伽马光谱。得出经身体体型和本底校正后的氮与氢计数之比，据此可估算蛋白质含量。该技术与通过氚稀释法测量水相结合，每次检查的总剂量当量（中子和氚β射线）小于0.5 mSv时，能够分别以4.2%、1.5%和6.3%的精度估算蛋白质、水和脂肪的含量。
