studies in normal persons, and its variability from person to person. For example, FDG accumulates in various structures in the head and neck,and in the ovaries and uterus of normal women during certain phases of the menstrual cycle. The case method of teaching has stood the test of time for more than a hundred years and is still valid as new modalities are developed and introduced into medical practice. The authors,both of whom have considerable experience in the performance and interpretation of PET-CT studies with FDG, have made an important contri- tion that will be of great value to nuclear medicine physicians,radiologists,oncologists, and other physicians with the responsibility of caring for patients with cancer. Capabilities and limitations are discussed in the context of speci?c problems and patients.