Musculoskeletal PET/CT utilizing 18F-NaF

Learning Objectives Recent increased accessibility to PET/CT and the availability of 18F-NaF as a skeletal imaging radiotracer, has lead to renewed interest in Positron-based bone imaging. In this educational exhibit we review updated consensus guidelines and discuss basic principles of practice encountered in routine clinical patient care.

In the year 2000, the FDA approved the handling of 18F for PET in the areas of oncology, cardiac perfusion assessment, neurology, and musculoskeletal imaging evaluation. Research studies have shown that PET Bone Imaging has improved sensitivity and specificity over conventional planar, as well as SPECT imaging. 18F-NaF, injected intravenously, rapidly equilibrates primarily in the extracellular fluid space as it does not bind to plasma proteins. There is prompt blood pool clearance with incorporation into the bone matrix through conversion of hydroxyapatite to fluoroapatite, dependent on regional blood flow. This occurs at twice the rate of bisphosponate derivatives. Studies have found preferential deposition of fluorine in the axial skeleton. We present cases that encompass the spectrum of disease encountered in a busy PET/CT practice. Interesting findings include variations in physiologic tracer distribution, as well as pathognomonic patterns appreciated in common disease processes, such as Paget’s Disease. We emphasize the importance of proper reading technique, including window and level settings for both the functional and anatomic portions of the modern day PET/CT image. We also explore, novel approaches to addressing challenging clinical cases, such as early phase imaging through utilization of list-mode technique