ICRP Publications 53, 62 and 80 give organ dose coefficients and effective doses to ICRP Reference Man and Child from established nuclear medicine procedures. However, an average Indian adult differs significantly from the ICRP Reference Man as regards anatomical, physiological and metabolic characteristics, and is also considered to have different tissue weighting factors (called here risk factors). The masses of total body and most organs are significantly lower for the Indian adult than for his ICRP counterpart (e.g. body mass 52 and 70 kg respectively). Similarly, the risk factors are lower by 20-30% for 8 out of the 13 organs and 30-60% higher for 3 organs. In the present study, available anatomical data of Indians and their risk factors have been utilised to estimate the radiation doses from administration of commonly used 99Tcm-labelled radiopharmaceuticals under normal and certain pathological conditions. The following pathological conditions have been considered for phosphates/phosphonates - high bone uptake and severely impaired kidney function; IDA - parenchymal liver disease, occlusion of cystic duct, and occlusion of bile duct; DTPA - abnormal renal function; large colloids - early to intermediate diffuse parenchymal liver disease, intermediate to advanced parenchymal liver disease; small colloids - early to intermediate parenchymal liver disease, intermediate to advanced parenchymal liver disease; and MAG3 - abnormal renal function, acute unilateral renal blockage. The estimated 'effective doses' to Indian adults are 14-21% greater than the ICRP value from administration of the same activity of radiopharmaceutical under normal physiological conditions based on anatomical considerations alone, because of the smaller organ masses for the Indian; for some pathological conditions the effective doses are 11-22% more. When tissue risk factors are considered in addition to anatomical considerations, the estimated effective doses are still found to be generally somewhat higher for the Indian, for both normal and pathological states (but lower than the values based on anatomical considerations alone). However, when the radiopharmaceutical is administered in quantities proportional to the body mass, the effective doses are 11-28% lower for the Indian under both normal and pathological conditions. It may be concluded that Indians are at a lower risk of radiation health detriment in comparison with the ICRP adult on administration of the various 99Tcm-labelled radiopharmaceuticals considered in this study.
国际放射防护委员会第 53、62 和 80 号出版物给出了国际放射防护委员会参考人和儿童在既定核医学程序中的器官剂量系数和有效剂量。然而,印度成年人在解剖、生理和新陈代谢特征方面与国际放射防护委员会参考人有很大不同,而且被认为具有不同的组织加权系数(此处称为风险系数)。印度成年人的全身质量和大多数器官的质量明显低于国际参考人计划的参考人(例如,身体质量分别为 52 千克和 70 千克)。同样,在 13 个器官中,8 个器官的风险系数低 20-30%,3 个器官的风险系数高 30-60%。本研究利用现有的印度人解剖学数据及其风险因素,估算在正常和某些病理情况下使用常用的 99Tcm 标记放射性药物所产生的辐射剂量。
磷酸盐/
膦酸盐--骨吸收率高和肾功能严重受损;
IDA--实质性肝病、胆囊管闭塞和胆管闭塞;
DTPA--肾功能异常;大胶体--早期至中期弥漫性实质肝病、中期至晚期实质肝病;小胶体--早期至中期实质肝病、中期至晚期实质肝病;以及 MAG3--肾功能异常、急性单侧肾阻塞。印度成年人的 "有效剂量 "估计值比国际放射防护委员会仅从解剖学角度考虑的正常生理条件下施用相同活度放射性药物的值高出 14-21%,因为印度人的器官较小;对于某些病理情况,有效剂量高出 11-22%。如果除解剖学因素外,还考虑组织风险因素,则发现印度人在正常和病理状态下的估计有效剂量仍普遍略高(但低于仅根据解剖学因素得出的数值)。然而,当放射性药物的剂量与体重成正比时,印度人在正常和病理状态下的有效剂量都要低 11-28%。由此可以得出结论,与国际放射防护委员会成人相比,印度人在施用本研究中考虑的各种 99Tcm 标记放射性药物时,辐射健康受损的风险较低。