Thirty patients will be enrolled in this study. There will be two administrations of 131I-anti-B1 given to patients, the "dosimetric dose" and the "radioimmunotherapy dose". The dosimetric dose will consist of an infusion of unlabeled Anti-B1 (450 mg) immediately followed by an infusion of Anti-B1 (35 mg) which has been trace labeled with 5mCi of 131I-anti-B1. The total whole body dosimetry dose is then calculated over an approximated one-week time interval from the radioactive clearance data obtained by the Whole Body anterior and posterior gamma camera scans. Based upon dosimetric data calculations specific for each individual patient, a radioimmunotherapy dose will be given consisting of an infusion of unlabeled Anti-B1 (450 mg)immediately followed by an infusion of 35 mg Anti-B1 including a patient specific dose of 131Iodine-Anti-B1. Calculations will be made such that in a dose escation study, whole body radiation doses of 30, 45, 60, and 75cGy will result from the administration of the therapeutic activity of 131I-anti-B1. The amount of the unlabeled Anti-B1 administered is not calculated on a body surface area basis, but is given to provide an excess of Anti-B1 independent of tumor burden, splenic uptake, or other causes.