Mozley P D, Zhu X, Kung H F, Selikson M H, Hickey J, Galloway S, Pfieffer N, Alavi A
Department of Radiology, University of Pennsylvania, Philadelphia.
J Nucl Med. 1993 Feb;34(2):208-13.
TISCH is an iodinated D1 specific dopamine receptor antagonist that may be useful as a SPECT imaging agent. This report documents its pharmacological safety in animals and its radiation dosimetry in humans. The dose of radiation that 123I-TISCH delivered to seven healthy subjects was estimated with the absorbed fraction technique. Conjugate images of the body were serially acquired for up to 24 hr after the administration of a known amount of activity. The count rates in the organs that could be visualized were measured on each image. These count rates were corrected for attenuation with 123I transmission scans. The doses to the other organs that did not take up enough activity to be visualized on the images were estimated with established models. The dosimetry was calculated for each subject individually before the results were averaged. Rapid biological washout minimizes the radiation exposure to most organs. The dose to the large bowel is limiting in healthy volunteers. The proximal colon receives about 0.67 rad/mCi (180 microGy/MBq) or about 5 rads for every 7.5 mCi of TISCH injected. This low radiation burden should make it feasible to study the D1 dopamine receptor in patients who have neuropsychiatric disorders before and after treatment.
TISCH是一种碘化的D1特异性多巴胺受体拮抗剂，可用作单光子发射计算机断层扫描（SPECT）成像剂。本报告记录了其在动物体内的药理安全性及其在人体中的辐射剂量学。采用吸收分数技术估算了123I-TISCH给予7名健康受试者的辐射剂量。在给予已知活度后，连续采集身体的共轭图像长达24小时。在每张图像上测量可观察到的器官的计数率。这些计数率通过123I透射扫描进行衰减校正。对于在图像上未摄取足够活度而无法观察到的其他器官，使用既定模型估算其剂量。在对结果进行平均之前，分别为每个受试者计算剂量学。快速的生物清除使大多数器官的辐射暴露降至最低。在健康志愿者中，大肠的剂量是限制因素。近端结肠每注射7.5毫居里的TISCH接受约0.67拉德/毫居里（180微戈瑞/兆贝可）或约5拉德。这种低辐射负担应使在患有神经精神疾病的患者治疗前后研究D1多巴胺受体成为可能。
