[Imaging of cancer activity and range of tumor involvement--applying to breast cancer].

In recent years, PET using mainly fluorine-18 fluorodeoxyglucose (FDG) has played a very large role in the management of breast cancer. Systemic, functional images can be obtained by whole body PET and can provide information that is not obtained by anatomical imaging modalities such as conventional X-ray computed tomography, X-ray mammography, or ultrasonography. The utility of FDG-PET for breast cancer patients has been established in every phase of the management of breast cancer, such as the differential diagnosis of breast cancer primary lesion, cancer staging, and posttreatment monitoring. For whole body FDG-PET that can assess the spread of systemic disease in a single examination, postoperative monitoring is one of the most useful applications in particular. In addition, the usefulness of PET for prediction of prognosis and assessment of treatment response has been reported along with the medical economical effect of FDG-PET for breast cancer patients. Moreover, it is expected that a new tracer other than FDG, such as fluorine-18 ion and [18F]-fluoro-17beta; estradiol (FES), and the new instruments such as PET-CT and positron emission mammography (PEM) can further contribute to the management of breast cancer. In this report, we will outline the benefits, limitations, and future prospects of PET for breast cancer.