FDG PET/CT has rapidly emerged as an invaluable combined imaging modality that provides both anatomic and functional information. This book, comprising a collection of images from oncology cases, is organized according to the role of FDG PET/CT in the evaluation and management of oncology patients, and only secondarily by organ or tumor entity. In this way, it reflects the issues that clinicians actually address, namely: identification of an unknown or unsuspected primary; determination of the extent of disease; evaluation of response to therapy; and surveillance after response, i.e., detection of recurrent disease. In total, 100 cases involving different primary tumors are presented to illustrate findings in these different circumstances.