COMBINED PET AND X RAY CT TOMOGRAPH FOR CLINICAL USE

这项研究计划的主要目标是设计、建造和 对具有以下功能的新断层摄影仪执行有限验证 在X射线CT或正电子断层扫描(PET)模式下操作。这个 建议将一台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，并旋转支架以获取 两种成像方式的完整投影数据集。体层摄影术将 因此，获取准确的功能和解剖图像 共同注册，不使用外部标志或内部地标。 次要的目标是使用CT数据来改进矫正 用于测量散射光子的衰减和污染的PET数据。 通过一种新的方式使用CT图像，低噪声衰减校正 可以产生PET的因子，并通过整合解剖学 将CT中的信息转化为最近开发的散射校正 方法，可以得到准确的散射校正结果。 18F-氟代脱氧葡萄糖(FDG)的应用正在迅速增长 PET的区域，肿瘤的葡萄糖代谢增加 被用来确定是否存在复发的胶质瘤与放射治疗 坏死、复发性结肠癌与手术疤痕和放射治疗的比较 变化，以及放射性坏死与反应性纵隔淋巴结。一个 PET在所有这些重要应用中的主要困难是 准确定位增加的葡萄糖摄取到特定的 解剖结构。虽然多通道图像对齐已经被 广泛地为大脑开发，但在 由于识别胸腔和腹部存在技术困难 常见结构和内部器官在内部移动的趋势 身体。在建议的联合模式中，PET/CT断层扫描，功能性 而解剖图像本质上是共同配准的。对于这项提议， 新型体层摄影术对脑出血的诊断能力的初步研究 局部性肿瘤将在10名患者中进行有限的系列治疗 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.