A Novel Technique for Performing Simultaneous Dual Radiotracer Imaging Studies in PET

项目摘要 正电子发射器导致检测到符合的511 keV湮没光子。因而是不可 可以在PET中进行双放射性示踪剂研究，如SPECT所做的那样，其中能量辨别 可以执行。这份资助申请的意义在于，它提出了一种方法， 在同一次PET成像期间注射两种PET放射性示踪剂。作为原则的证明，我们将 注射癌症成像中常用的两种放射性示踪剂：FMISO（肿瘤缺氧）和FLT （细胞增殖）。如果成功，我们的研究将显示提供空间的可行性。 在同一成像会话内描绘肿瘤缺氧和增殖。但是应当 我们的方法并不局限于FMISO和FLT;它可以应用于许多 放射性示踪剂对。与PET/MR的情况一样，双示踪剂成像使得可以测量两个 肿瘤的表型特性，当肿瘤处于相同状态时，其可以随时间变化。 此外，与连续采集相比，它为患者提供了更大的便利，例如，在不同的日子。在 因此，本项目提出验证一种同时成像肿瘤缺氧和 在动物肿瘤模型中的单次PET研究中观察增殖。动态PET采集是 在两种放射性示踪剂18FMISO和18FLT依次注射的同时， 及时成像信号的回顾性18 FMISO/18 FLT分离将基于先验 组织药代动力学知识和区分血液中这两种放射性示踪剂的能力 通过薄层色谱法（TLC）对样品进行分析。如果成功，这种方法，即立即 可转化为临床，将为患者研究奠定基础，其中双放射性示踪剂研究 将是有用的。

Project Summary Positron emitters result in the detection of coincident 511 keV annihilation photons. Thus, it is not possible to perform dual radiotracer studies in PET as is done SPECT, where energy discrimination may be performed. This grant application's significance lies in that it proposes a method to separate two PET radiotracers injected during the same PET imaging session. As a proof of principle, we shall inject two radiotracers commonly employed in cancer imaging: FMISO (tumor hypoxia) and FLT (cellular proliferation). If successful, our study would show the feasibility to provide the spatial delineation of tumor hypoxia and proliferation within the same imaging session. Although it will be applied to both, our approach is not restricted to FMISO and FLT; it could be applied to a number of radiotracer pairs. As is the case of PET/MR, dual tracer imaging makes it possible to measure two phenotypic properties of the tumor, which may vary temporally when the tumor is in the same state. Moreover, it offers greater patient convenience than sequential acquisitions, e.g., on separate days. In this project, therefore, we propose to validate a method to simultaneously image tumor hypoxia and proliferation within a single PET study in an animal tumor model. A dynamic PET acquisition is performed while the two radiotracers, 18FMISO and 18FLT, are injected sequentially, closely staggered in time. Retrospective 18FMISO /18FLT separation of imaging signals will be based on a priori knowledge of tissue pharmacokinetics and the ability to distinguish these two radiotracers in blood samples by thin-layer chromatography (TLC). If successful, this approach, which is immediately translatable into the clinic, would set the stage for patient studies in which dual radiotracer studies would be useful.