The main goal of the second edition of this book is to update the content on the rapidly growing field of lymphoscintigraphy, a radionuclide-based imaging procedure that provides information on the functional status of the lymphatic system. Although the technique was originally introduced to identify the cause of peripheral edema (i.e., blockage of the venous or lymphatic circulation), more recent and widespread applications include radioguided biopsy of the sentinel lymph node in patients with solid cancers. This procedure is crucial for the adequate planning of oncologic surgery in a growing number of cancers, most notably breast cancer, cutaneous melanoma, head and neck cancers, penile cancer, and cervical cancer.