Nuclear medicine is important in the diagnosis, staging, and long-term surveillance of a number of pediatric cancers. Skeletal scintigraphy is used to evaluate primary skeletal cancers, such as osteosarcoma and Ewing sarcoma, and nonskeletal cancers such as neuroblastoma, lymphoma, medulloblastoma, rhabdomyosarcoma, and retinoblastoma. Metaiodobenzylguanidine scintigraphy is valuable in examinations of children with neuroblastoma. The therapeutic response of primary bone and brain tumors can be assessed using Tl-201 and Tc-99m MIBI scintigraphy. Imaging strategies for staging and monitoring the therapeutic response of Hodgkin's lymphoma include Ga-67 citrate scintigraphy. Pediatric oncologic applications of positron emission tomography are being investigated extensively.