Functional Imaging in Breast Cancer: Focus on PET-CT

This chapter describes the utility and applicability of diagnostic nuclear medicine techniques, primarily positron emission tomography-computed tomography (PET-CT) imaging, in the management of breast cancer. The advantages and disadvantages of PET-CT compared to the more widely used anatomical imaging modalities are detailed, wherever applicable, with the inferences supported by the currently available evidence base in the literature. A brief background on breast cancer epidemiology and relevant biology is provided, followed by an overview of current imaging techniques. We then review the role of the PET-CT performed with the most commonly used radiotracer, i.e. 18F-FDG, in a stepwise manner, in various clinical scenarios associated with breast cancer that include lesion characterization, staging, treatment response assessment and surveillance for recurrence. Novel indications for molecular imaging where tracers other than 18F-FDG have shown potential applicability, like evaluation of hormone receptor status, are then discussed. Recent advances in PET-CT imaging, including radiomics, employing the concepts of artificial intelligence and machine learning, as applied to breast cancer, are briefly described towards the end.