A MICRO CT/PET SCANNER FOR IN VIVO SCREENING OF MICE

描述（由申请人提供）：本提案的目的是开发用于小鼠成像的集成microCT/microPET扫描仪。小动物成像技术开始在生物医学研究中发挥重要作用，提供了以完全非侵入性方式重复测量完整实验室动物生物过程的机会。结合分子成像（PET）与高分辨率解剖成像（CT）提供的优势，无论是在数据解释和数据量化相比，单独使用任何一种方式。这种独特的多模态设备的应用将包括在人类癌症小鼠模型中研究肿瘤动力学和转移，基因递送和表达的成像以及体内标记细胞的跟踪。我们建议建立一个集成系统，采用非晶硒（a-Se）的X射线探测器技术，一个紧凑的X射线源和高分辨率闪烁探测器在一个共面的几何形状，允许CT和PET数据被同时采集。初步研究表明，这种做法是可行的。在本提案中，对X射线光谱和过滤影响的详细研究将确定适当的X射线管设置/过滤器，以在最低辐射剂量下产生最高的对比度噪声比。a-Se探测器将被表征并与广泛使用的基于磷光体/CCD的探测器技术进行比较。将测量CT扫描对小鼠的辐射剂量，并研究其生物效应（如有）。将CT和PET探测器组件安装到适合在体模和小鼠中进行初步成像研究的机架中。将研究CT数据用于校正PET数据中的光子衰减和部分容积效应。最后，将在同一受试者的重复研究和跨受试者的个体研究中评估成像解剖和代谢的再现性。

DESCRIPTION (provided by applicant): The objective of this proposal is to develop an integrated microCT/microPET scanner for mouse imaging. Small animal imaging technologies are starting to play an important role in biomedical research, offering the opportunity to make repeated measurements of biological processes in intact laboratory animals in a completely non-invasive fashion. Combining molecular imaging (PET) with high resolution anatomic imaging (CT) offers advantages both in data interpretation and in data quantification compared with using either modality independently. Applications for this unique multi-modality device would include studies of tumor kinetics and metastasis in mouse models of human cancer, imaging of gene delivery and expression, and tracking of labeled cells in vivo. We propose to build an integrated system that incorporates amorphous selenium (a-Se) x-ray detector technology, a compact x-ray source and high resolution scintillation detectors in a co-planar geometry allowing CT and PET data to be acquired simultaneously. Preliminary studies have indicated the feasibility of this approach. In this proposal, detailed studies of x-ray spectra and the influence of filtration will determine appropriate x-ray tube settings/filters that produce the highest contrast to noise ratio for the lowest radiation dose. The a-Se detector will be characterized and compared with widely used phosphor/CCD based detector technology. The radiation dose to the mouse from the CT scan will be measured, and its biological effect, if any, investigated. The CT and PET detector components will be mounted into a gantry suitable for preliminary imaging studies in phantoms and in mice. The use of the CT data for correcting photon attenuation and for partial volume effects in the PET data will be investigated. Finally, the reproducibility of imaging anatomy and metabolism will be assessed both in repeat studies of the same subject, and in individual studies across subjects.