PET/CT today and tomorrow.
PET/CT today and tomorrow.
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发表时间：
2004
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通讯作者：
D. Townsend;J. Carney;J. Yap;N. Hall
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作者：
D. Townsend;J. Carney;J. Yap;N. Hall
众所周知，通过 PET 对功能异常进行准确的解剖定位是有问题的。尽管 18F-FDG 等非特异性示踪剂可以使某些正常解剖结构可视化，但空间分辨率通常不足以进行病理定位。将 PET 与高分辨率解剖成像模式（例如 CT）相结合可以解决定位问题，只要两种模式的图像准确配准即可。然而，基于软件的配准技术难以解释患者体位的差异和内脏器官的不自主运动，通常需要劳动密集型的非线性映射，而这种映射可能无法收敛到令人满意的结果。在同一台扫描仪中采集 CT 和 PET 图像，无需软件配准，并且通常可以在单次扫描中提供准确对齐的解剖结构和功能图像。讨论 最近，人们探索将 CT 扫描仪与 PET 扫描仪并用通用患者床和操作控制台串联放置，作为解剖和功能图像配准的解决方案。治疗床在两种模式之间的轴向平移使得能够在单个成像会话期间获取 CT 和 PET 数据。此外，CT 图像还可用于生成 PET 发射数据的无噪声衰减校正因子。通过最大限度地减少 CT 和 PET 扫描之间的患者移动，并考虑两种模式的轴向分离，可以获得准确配准的解剖和功能图像。自 5 年前推出第一台 PET/CT 原型以来，已有数千名癌症患者使用 PET/CT 组合设备进行了扫描。在过去 3 年中，已经出现了许多采用多探测器螺旋 CT 扫描仪和高性能 PET 设备的商业设计。初步经验表明，与单独读数相比，联合研究的解释的准确性和置信度有所提高，特别是在区分病理学和正常生理摄取以及精确定位异常病灶的能力方面。结论 组合式 PET/CT 扫描仪代表了技术的重要发展，有助于将分子成像推向癌症诊断、分期和治疗监测的最前沿。
UNLABELLED Accurate anatomic localization of functional abnormalities seen with PET is known to be problematic. Even though nonspecific tracers such as 18F-FDG visualize certain normal anatomic structures, the spatial resolution is generally inadequate for localization of pathology. Combining PET with a high-resolution anatomic imaging modality such as CT can resolve the localization issue, as long as the images from the two modalities are accurately coregistered. However, software-based registration techniques have difficulty accounting for differences in patient positioning and involuntary movement of internal organs, often necessitating labor-intensive nonlinear mapping that may not converge to a satisfactory result. Acquiring both CT and PET images in the same scanner obviates the need for software registration and routinely provides accurately aligned images of anatomy and function in a single scan. DISCUSSION A CT scanner positioned in tandem with a PET scanner and with a common patient couch and operating console has recently been explored as a solution to anatomic and functional image registration. Axial translation of the couch between the two modalities enables both CT and PET data to be acquired during a single imaging session. In addition, the CT images can be used to generate noiseless attenuation correction factors for the PET emission data. By minimizing patient movement between the CT and PET scans, and after accounting for the axial separation of the two modalities, accurately registered anatomic and functional images can be obtained. Since the introduction of the first PET/CT prototype a little over 5 years ago, several thousand cancer patients have been scanned on combined PET/CT devices. In the past 3 years, a number of commercial designs have become available featuring multidetector spiral CT scanners and high-performance PET devices. Initial experience has demonstrated an increased level of accuracy and confidence in the interpretation of the combined study compared with separate readings, particularly in the ability to distinguish pathology from normal physiologic uptake and to precisely localize abnormal foci. CONCLUSION Combined PET/CT scanners represent an important evolution in technology that is helping to bring molecular imaging to the forefront in cancer diagnosis, staging, and therapy monitoring.