Sureshbabu Waheeda, Mawlawi Osama
Nuclear Medicine, M.D. Anderson Cancer Center, Houston, Texas 77042, USA.
J Nucl Med Technol. 2005 Sep;33(3):156-61; quiz 163-4.
The purpose of this paper is to introduce the principles of PET/CT imaging and describe the artifacts associated with it. PET/CT is a new imaging modality that integrates functional (PET) and structural (CT) information into a single scanning session, allowing excellent fusion of the PET and CT images and thus improving lesion localization and interpretation accuracy. Moreover, the CT data can also be used for attenuation correction, ultimately leading to high patient throughput. These combined advantages have rendered PET/CT a preferred imaging modality over dedicated PET. Although PET/CT imaging offers many advantages, this dual-modality imaging also poses some challenges. CT-based attenuation correction can induce artifacts and quantitative errors that can affect the PET emission images. For instance, the use of contrast medium and the presence of metallic implants can be associated with focal radiotracer uptake. Furthermore, the patient's breathing can introduce mismatches between the CT attenuation map and the PET emission data, and the discrepancy between the CT and PET fields of view can lead to truncation artifacts. After reading this article, the technologist should be able to describe the principles of PET/CT imaging, identify at least 3 types of image artifacts, and describe the differences between PET/CT artifacts of different causes: metallic implants, respiratory motion, contrast medium, and truncation.
本文的目的是介绍PET/CT成像的原理，并描述与之相关的伪影。PET/CT是一种新的成像模式，它在一次扫描过程中整合了功能（PET）和结构（CT）信息，使PET和CT图像能够完美融合，从而提高病变定位和解读的准确性。此外，CT数据还可用于衰减校正，最终实现高患者通量。这些综合优势使PET/CT成为比专用PET更受欢迎的成像模式。尽管PET/CT成像具有诸多优势，但这种双模态成像也带来了一些挑战。基于CT的衰减校正可能会产生伪影和定量误差，进而影响PET发射图像。例如，使用造影剂和存在金属植入物可能与局灶性放射性示踪剂摄取有关。此外，患者的呼吸会导致CT衰减图与PET发射数据之间出现不匹配，而CT和PET视野之间的差异会导致截断伪影。读完本文后，技术人员应能够描述PET/CT成像的原理，识别至少3种图像伪影类型，并描述不同原因（金属植入物、呼吸运动、造影剂和截断）导致的PET/CT伪影之间的差异。
