Dosing;"Dosimetric Doses", Intravenous (IV) administration of unlabeled TST (0, 95 or 475 mg) was administered to determine the dose of unlabeled TST that optimized the radiation dose to the tumor. This was followed by 5 mCi of I-131 TST. Serial whole body sodium iodide scintillation probe counts were obtained daily, for at least 5 days, in order to determine the rate of whole body clearance of radioactivity (residence time). The residence time was used to determine the radioactive clearance from the subject and subsequently the activity (in mCi) of Iodine-131 required to deliver the desired TBD of radiation during the therapeutic dose of TST/I-131 TST. Because 475 mg was determined to be the optimal pre-dose of tositumomab in the first subjects entered, the last 34 subjects received a single dosimetric dose that was preceded by an infusion of 475 mg of tositumomab (Source Data: Listing 13).