Siwek R A, Burkinshaw L, Oxby C B, Robinson P A
Phys Med Biol. 1984 Jun;29(6):687-701. doi: 10.1088/0031-9155/29/6/005.
The Leeds facility for in vivo neutron activation analysis has been modified and calibrated for the simultaneous measurement of nitrogen, potassium, sodium, chlorine, phosphorus and calcium in obese patients weighing up to 210 kg. The effects of body size and shape were incorporated into the calibration by measuring 14 anthropomorphic phantoms of known composition representing individual patients being treated for obesity. The phantoms were constructed from tissue substitutes representing lean, skeletal and adipose tissues, arranged to simulate the distributions of the corresponding tissues within the patients, as visualised by CT scanning. The precision of the method, determined by measuring a single phantom ten times over a period of ten weeks, is between two and three per cent for all elements except calcium, for which it is 11.3%. Accuracy is estimated to be similar to precision. The procedure has been used to study changes in body composition of patients undergoing therapeutic starvation.
利兹体内中子活化分析设备已进行了改装和校准，可用于同时测量体重达210千克的肥胖患者体内的氮、钾、钠、氯、磷和钙。通过测量14个已知成分的拟人化体模（代表接受肥胖治疗的个体患者），将体型和形状的影响纳入校准过程。这些体模由代表瘦组织、骨骼组织和脂肪组织的组织替代物构建而成，其排列方式模拟了患者体内相应组织的分布，这是通过CT扫描可视化呈现的。通过在十周时间内对单个体模进行十次测量来确定该方法的精密度，除钙元素外，所有元素的精密度在2%至3%之间，钙元素的精密度为11.3%。据估计，准确度与精密度相近。该程序已用于研究接受治疗性饥饿的患者身体成分的变化。
