In this study, we propose to apply therapy with Bexxar, a radiolabeled anti-CD20 antibody. Bexxar Therapeutic Regimen is composed of the murine anti-CD20 monoclonal antibody Tositumomab and Iodine I 131 Tositumomab. Iodine I 131 Tositumomab is a radio-iodinated derivative of Tositumomab that has been covalently linked to Iodine-131.