A Novel Device to Allow Zoom-In Imaging for PET Scanners

描述（由申请人提供）： 正电子发射断层扫描（PET）已被广泛接受的临床成像肿瘤，心脏和神经系统的应用。当前的设计趋势倾向于高效率的中分辨率扫描仪，以最大限度地减少全身成像协议的扫描时间。PET成像的最小可检测对象和定量精度与扫描仪分辨率直接相关。新兴的分子成像领域通过体内成像研究疾病模型、新药的药代动力学和使用小实验室动物的基因表达已经显示出有希望的结果。从实验室动物研究中开发的技术和模型将很快需要临床试验来验证和进一步开发人类应用。这种翻译的成功依赖于高分辨率的人体PET系统，以推进分子成像研究的临床应用。该项目的目标是开发所需的技术，以专用高分辨率PET扫描仪的一小部分成本提供感兴趣器官的高分辨率PET图像。所提出的设计是一种探测器插入物，可以连接到全身PET扫描仪上，以在较小的视场内提供高分辨率图像，这一概念类似于在MRI中使用表面线圈来提高其图像分辨率。由于该设备被设计为辅助检测器，其成本明显低于完整系统。感兴趣区域内的图像分辨率可以低至3mm FWHM或更小，这取决于探测器的设计、插入物的尺寸和原始系统分辨率。这种装置的灵敏度可以是使用相同检测器的独立高分辨率系统的两倍以上。该项目的R21阶段提供了设计的可行性研究，而R33阶段是为现有的PET扫描仪实现原型设备。R21阶段的具体目标是（1）开发基于APD的高分辨率PET探测器，（2）通过模拟和实验验证所提出设备的图像分辨率和灵敏度，以及（3）评估设备散射的影响并开发抑制技术。R33阶段的具体目标是：（1）构建器械，（2）将器械集成到现有PET扫描仪中，（3）开发特殊几何结构的图像重建算法，以及（4）测试器械并评价其性能。原型设备的直接应用包括头颈部肿瘤和淋巴结、脑肿瘤和脑功能的高分辨率成像。该设计可以扩展到开发特殊的插入物，以成像涉及乳腺、肺和前列腺的癌症。该项目的成果将使临床和研究应用的高分辨率人体PET成像取得重大进展。

DESCRIPTION (provided by applicant): Positron emission tomography (PET) has been widely accepted for clinical imaging for oncologic, cardiac and neurological applications. The current trend of design favors high-efficiency median-resolution scanners to minimize the scan time for whole body imaging protocols. The smallest object detectable and the quantitative accuracy of PET imaging are directly related to the scanner resolution. The emerging field of molecular imaging to study disease models, pharmacokinetics of new drugs, and gene expression using small laboratory animals via in vivo imaging has shown promising results. The techniques and models developed from laboratory animal studies will soon require clinical trials to provide validation and further development for human applications. The success of such translation relies on high-resolution human PET systems to advance the molecular imaging research to clinical applications. The goal of this project is to develop the technology required to provide high-resolution PET images of the organs of interest at a fraction of the cost of a dedicated high-resolution PET scanner. The proposed design is a detector insert that can be attached to a whole-body PET scanner to provide high-resolution images within a smaller field of view, a concept similar to the use of surface coils in MRI to improve its image resolution. Since the device is designed as an accessory detector, its cost is significantly lower than a complete system. The image resolution within the regions of interest can be as low as 3 mm FWHM or smaller, depending on the design of the detectors, the dimension of the insert, and the original system resolution. The sensitivity of such a device may be more than twofold of a stand-alone high resolution system using the same detectors. The R21 phase of this project provides feasibility study of the design, while the R33 phase is to implement a prototype device for an existing PET scanner. The specific aims of the R21 phase are (1) develop APD-based high-resolution PET detector, (2) validate the image resolution and sensitivity of the proposed device via simulation and experiment, and (3) evaluate the effect of scatter from the device and develop a rejection technique. The specific aims of the R33 phase are: (1) Construct the device, (2) integrate the device to an existing PET scanner, (3) develop image reconstruction algorithms for the special geometry, and (4) test the device and evaluate its performance. The immediate applications of the prototype device include high-resolution imaging for head and neck tumors and lymph nodes, brain tumors, and brain functions. The design earl be extended to develop special inserts to image cancers involving breasts, lungs, and prostate. The outcome of this project will make a significant advancement in high resolution human PET imaging for both clinical and research applications.