 Unlabelled tositumomab together with iodine-labelled tositumomab was called Bexxar and a personalized regimen using Bexxar was approved for the treatment of relapsed or chemotherapy/rituxan-refractory Non-Hodgkin lymphoma in 2003.The treatment regimen was personalized for each person receiving the drug in order to maximize the radiation delivered to the tumor and to minimize the amount of radiation to which the person would be exposed.A first dose of labelled antibody was given once, and whole-body radiation was measured with a gamma camera over seven days.