RT Journal Article SR Electronic T1 Detecting the damage of D2 receptor by methamphetamine in rats with multi-pinhole SPECT JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 241P OP 241P VO 48 IS supplement 2 A1 Chia-Jung Chang A1 Li-Chung Huang A1 Hsueh-Hsuan Liu A1 An-Shoei Yang A1 Cheng-Fu Chang A1 Chia-Chieh Chen YR 2007 UL http://jnm.snmjournals.org/content/48/supplement_2/241P.2.abstract AB 1124 Objectives: Neuroimaging study of the pharmacokinetics and pharmacodynamics of abused substances in rodent model is a promising approach to the development of novel drugs and treatment strategies. A significant toxicity of methamphetamine to dopamine system has been reported in methamphetamine abusers. To establish a platform for imaging dopamine receptors in rat, this work used D2 receptor tracer [123I] IBZM and small animal SPECT equipped with a recently developed multi-pinhole collimator to monitor D2 receptor availabilities in rat brains prior and post administration of methamphetamine. Methods: The tracer [123I]IBZM was prepared by directly oxidative iodination of the phenolic precursor BZM((S)-2-hydroxy-6-methoxy-N-[(1-ethyl-2-pyrrolidiny)methyl] benzamide) with high purity 123I-ammonia iodide(obtained from TR30/15 cyclotron, INER, Taiwan). Methamphetamine in a dosage of 5 mg/kg was administrated via i.p. injection to SD rats 4 times in one hour intervals to trigger long term damage to the dopamine system. SPECT tomographic images and x-ray computed tomography (CT) were acquired 90 minutes after introducing [123I]IBZM via the tail vein. A double-headed microSPECT system (X-SPECT, Gamma Medica Inc.) equipped with PH65 muiti-pinhole collimators was employed for the scan. The SPECT/CT fused images were then displayed on Reveal MVS to draw regions of interest (ROIs) in the striatum and cerebellum for semi-quantitative analysis. Results: [123I]IBZM with radiochemical purity higher than 90% as determined by a radio-TLC was obtained. SPECT image displayed significant specific binding in striatum was visualized in rat prior drug administration. The striatum binding ratio of control group as calculated as voxel intensity had 14.7 times of differences when compared with drug treatment rats. Conclusions: This study demonstrated that using [123I]IBZM and muti-pinhole SPECT, we are capable to semi-quantitatively assessing the availability of D2 receptor in rat model. This imaging platform as well as the long term D2 receptor toxicity rat model can be used to evaluate the brain function in substance abuse and during preclinical studies.