COMBINED PET AND X RAY CT TOMOGRAPH FOR CLINICAL USE

本研究计划的主要目标是设计、建造和 对具有以下能力的新断层扫描仪进行有限确认 在X射线CT或正电子断层扫描（PET）模式下操作。的 建议是将X射线CT和两个PET探测器阵列安装在 同一机架内的单个支架，并旋转支架以采集 两种成像模式的完整投影数据集。断层扫描仪将 因此获取功能和解剖图像， 共配准，不使用外部标记或内部标志。 第二个目的是使用CT数据来改善 PET数据的衰减和散射光子的污染。 通过以一种新的方式使用CT图像， 可以生成PET的因素，并且通过整合解剖学因素， 将来自CT的信息转化为最近开发的散射校正 方法，可以获得精确的散射校正。 18F-氟脱氧葡萄糖（FDG）的使用是一个快速增长的应用 PET区域，其中肿瘤的葡萄糖代谢增加 用于确定复发胶质瘤与放射治疗的存在 坏死、复发性结肠癌与手术瘢痕和放射 变化和放射性坏死与反应性纵隔淋巴结。一 PET在所有这些重要应用中的主要困难是 将增加的葡萄糖摄取准确定位到特定的 解剖结构虽然多模态图像对准已经被 广泛开发的大脑，很少有工作已经完成， 由于技术上的困难， 共同的结构和内部器官在内部移动的趋势 身体在所提出的组合模式PET/CT断层扫描仪中，功能 并且解剖图像本质上是共配准的。对于这一提议， 对新型断层扫描仪检测和 局部肿瘤将在10名患者的有限系列中进行， 已知的恶性疾病。

The primary goal of this research proposal is to design, construct and perform a limited validation of a new tomograph which has the capability of operating either in X-ray CT or positron tomography (PET) mode. The proposal is to mount an X-ray CT and two arrays of PET detectors on a single support within the same gantry, and rotate the support to acquire a full projection data set for both imaging modalities. The tomograph will therefore acquire functional and anatomical images which are accurately coregistered, without the use of external markers or internal landmarks. A secondary objective is to use the CT data to improve the correction of the PET data for attenuation and for contamination from scattered photons. By using the CT image in a novel way, low-noise attenuation correction factors for PET can be generated, and by integrating the anatomical information from the CT into recently-developed scatter correction methods, an accurate scatter correction can be obtained. The use of 18F-fluorodeoxyglucose (FDG) is a rapidly growing application area for PET, in which the increased glucose metabolism of neoplasms has been used to determine the presence of recurrent glioma versus radiation necrosis, recurrent colon carcinoma versus surgical scar and radiation changes, and radiation necrosis versus reactive mediastinal lymph node. A major difficulty in all these important applications of PET is the accurate localization of the increased glucose uptake to a specific anatomical structure. While multi-modality image alignment has been extensively developed for the brain, little work has been done in the thorax and abdomen owing to the technical difficulties of identifying common structures and to the tendency for internal organs to move within the body. In the proposed combined modality PET/CT tomograph, functional and anatomical images are intrinsically co-registered. For this proposal, a preliminary study of the capability of the new tomograph to detect and localize tumors will be performed in a limited series of ten patients with known malignant disease.