Figure. Total body scintigraphy in a patient with metastatic neuroblastoma 42 hours after injection of the l3ll-3F8. the monoclonal antibody specific for the ganglioside GD2. A large primary tumor was found in the lower abdomen with involvement of the right pelvis and sacrum. The sharp cut-off in the superior border of the tumor coincided with the lower edge of the radiation port through which external beam radiation (2,000 cGy) was given two weeks earlier. Metastatic disease was found in the cranium, left neck, spine, right chest, and left humerus. Except for the cervical tumor, all the other metastatic sites were not suspected from previous evaluations, based on bone scan or clinical examination.