Nyberg S, Farde L, Halldin C
Karolinska Institute, Department of Clinical Neuroscience, Karolinska Hospital, Stockholm, Sweden.
Psychiatry Res. 1996 Oct 7;67(3):163-71. doi: 10.1016/0925-4927(96)02921-6.
Central D2 dopamine receptor occupancy may be a useful measure to establish clinical guidelines for optimal antipsychotic drug treatment. The use of positron emission tomography (PET) to explore quantitative relationships among D2 receptor occupancy and clinical effects depends on the reliability of such measurements. The calculation of D2 receptor occupancy using [11C]raclopride is routinely based on a ratio-equilibrium analysis, in which the ratio of radioactivity concentration in the striatum to that in the cerebellum is determined. To examine the reliability of such ratios, a test-retest analysis was performed in four schizophrenic patients treated with haloperidol decanoate. PET experiments with [11C]raclopride were repeated in each subject during the same day. The putamen to cerebellum ratio (P/C ratio) ranged from 1.44 to 1.07 among the four patients, corresponding to a D2 receptor occupancy of 62 to 71%. In each subject, the P/C ratios remained highly similar, with quotients 0.98, 1.01, 1.04 and 1.06 between the two experiments. The high test-retest reproducibility of the P/C ratios indicates that measurements of D2 receptor occupancy with the present methods are highly reliable, and support the further use of PET to optimize the drug treatment of schizophrenia.
中枢D2多巴胺受体占有率可能是建立最佳抗精神病药物治疗临床指南的一项有用指标。利用正电子发射断层扫描（PET）来探究D2受体占有率与临床疗效之间的定量关系，取决于此类测量的可靠性。使用[11C]雷氯必利计算D2受体占有率通常基于比值平衡分析，即测定纹状体与小脑中放射性浓度的比值。为检验此类比值的可靠性，对4例接受癸酸氟哌啶醇治疗的精神分裂症患者进行了重测分析。在同一天对每位受试者重复进行了[11C]雷氯必利PET实验。4例患者的壳核与小脑比值（P/C比值）在1.44至1.07之间，对应的D2受体占有率为62%至71%。在每位受试者中，两次实验之间的P/C比值保持高度相似，商数分别为0.98、1.01、1.04和1.06。P/C比值的高重测再现性表明，采用目前方法测量D2受体占有率具有高度可靠性，并支持进一步利用PET来优化精神分裂症的药物治疗。
