Pimlott Sally L
West of Scotland Radionuclide Dispensary, North Glasgow University Hospitals NHS Trust, Western Infirmary, Dumbarton Rd, Glasgow, G11 6NT, UK.
Nucl Med Commun. 2005 Mar;26(3):183-8. doi: 10.1097/00006231-200503000-00002.
Over the last 20 years a number of radiotracers that target various neurotransmitter systems have been developed for use in imaging studies in psychiatry, but there are many more targets still to be investigated. The development of a radiotracer for clinical positron emission tomography (PET) or single photon emission computed tomography (SPECT) neuroimaging studies can be a complex and lengthy process with few imaging agents successfully progressing into clinical human studies. One of the most challenging aspects in the procedure is the development of a rapid and simple radiosynthesis protocol to obtain the potential radiotracer with adequate specific activity, isolated radiochemical yield and radiochemical purity for human imaging. Once a candidate has been radiolabelled, full characterization of the radiotracer is required before it can be used in clinical human studies. Pre-clinical studies include investigation into the binding distribution, pharmacokinetics, metabolism, toxicology and dosimetry of a radiotracer. There are many points during the development procedure where a potential radiotracer can be rejected. Due to interspecies differences the development of a radiotracer can either go too far with an unsuccessful candidate or can potentially lead to rejection of a candidate too soon. It is only when the radiotracer has been used in humans can we be certain that a radiotracer is a useful imaging agent for clinical research studies. The development of new technologies, such as micro-PET or SPECT can only improve our ability to predict the success of a radiotracer.
在过去20年里，已经开发出了多种针对不同神经递质系统的放射性示踪剂，用于精神病学的成像研究，但仍有许多靶点有待研究。开发用于临床正电子发射断层扫描（PET）或单光子发射计算机断层扫描（SPECT）神经成像研究的放射性示踪剂可能是一个复杂而漫长的过程，很少有成像剂能成功进入人体临床研究。该过程中最具挑战性的方面之一是开发一种快速简便的放射性合成方案，以获得具有足够比活度、分离放射性化学产率和放射性化学纯度的潜在放射性示踪剂用于人体成像。一旦候选物被放射性标记，在用于人体临床研究之前，需要对放射性示踪剂进行全面表征。临床前研究包括对放射性示踪剂的结合分布、药代动力学、代谢、毒理学和剂量学的研究。在开发过程中有许多环节，潜在的放射性示踪剂可能会被淘汰。由于种间差异，放射性示踪剂的开发可能会因候选物不成功而走得太远，或者可能过早导致候选物被淘汰。只有当放射性示踪剂用于人体时，我们才能确定它是一种用于临床研究的有用成像剂。新技术的发展，如微型PET或SPECT，只能提高我们预测放射性示踪剂成功与否的能力。
