The development of positron-emission tomography (PET) combined with computed tomography (CT), PET/CT, with near simultaneous acquisition capability has addressed the limited spatial resolution of PET and improved the anatomical localization of radiotracer uptake detected by PET. The combined imaging modality allows for CT-based attenuation correction of the PET emission scans, improving image quality and decreasing scan time and diagnostic CT examinations. Studies have shown that PET/CT is more accurate, more sensitive, and more specific than either modality alone. These benefits, however, come at the expense of increased radiation dose to the patient. PET/CT scanners are widely used and have almost totally replaced standalone PET systems. Optimized protocols to reduce dose while maintaining sufficient image quality as well as careful patient selection are important to avoid unnecessary exposure and to ensure high-quality images to inform clinical management decisions when a PET/CT study is needed. It is important to always consider ways to reduce radiation dose without compromising diagnostic quality.
After reading this article, the participant should be able to:
- Define parameters that impact the absorbed dose of PET radiopharmaceuticals.
- Identify CT acquisition parameters that influence radiation dose.
- Describe the clinical role of PET/CT in oncology, neurology, and cardiology.
Categories: Nuclear Medicine, Computed Tomography