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

描述(由申请人提供)：本提案的目标是开发一种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，它提供了以完全非侵入性的方式对完整的实验室动物的生物过程进行重复测量的机会。将分子成像(PET)和高分辨率解剖成像(CT)相结合，与单独使用任何一种方法相比，在数据解释和数据量化方面都具有优势。这种独特的多模式设备的应用将包括研究肿瘤动力学和人类癌症小鼠模型中的转移，基因传递和表达的成像，以及体内标记细胞的跟踪。我们建议建立一个集成系统，该系统结合了非晶态硒(a-Se)X射线探测器技术、紧凑的X射线源和共面几何结构的高分辨率闪烁探测器，允许同时获取CT和PET数据。初步研究表明，这一方法是可行的。在这项建议中，对X射线光谱和过滤的影响的详细研究将确定适当的X射线管设置/过滤器，以便在最低的辐射剂量下产生最高的对比度和噪声比。对a-Se探测器进行了表征，并与广泛使用的基于荧光粉/电荷耦合器件的探测器技术进行了比较。将测量CT扫描对小鼠的辐射剂量，并调查其生物学效应。CT和PET探测器组件将安装在适合在模体和小鼠身上进行初步成像研究的龙门上。将研究如何使用CT数据来校正PET数据中的光子衰减和部分体积效应。最后，影像解剖学和新陈代谢的重复性将在同一对象的重复研究和跨对象的单独研究中进行评估。

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.