Iodine I 131 Tositumomab or Yttrium Y 90 Ibritumomab Tiuxetan in Treating Patients With Non-Hodgkin's Lymphoma

"Tumor absorbed dose calculation using patient-specific 3D-RD dosimetry software.~Patients receive dosimetric tositumomab IV over 60 minutes followed by iodine I 131 (\^131I) tositumomab IV over 20 minutes on day 0. Patients undergo PET/CT scans and SPECT/CT scans on days 0; 2, 3 or 4; and 6 or 7. Patients who have acceptable biodistribution receive therapeutic tositumomab IV over 60 minutes followed by \^131I tositumomab IV over 20 minutes on approximately day 7."

"Doses calculated using conventional dosimetry software.~Patients receive dosimetric rituximab IV followed by indium In 111 (\^111In) ibritumomab tiuxetan IV over 10 minutes on day 1. Patients undergo positron emission tomography (PET)/CT scans and single-photon emission computed tomography (SPECT)/CT scans between 2-24, 48-72, and 90-120 hours after \^111In ibritumomab tiuxetan administration. Patients who have acceptable biodistribution receive therapeutic rituximab IV followed by yttrium Y 90 ibritumomab tiuxetan IV over 10 minutes between days 7-9."