Treatment options for patients with relapsed lymphoma include standard-dose chemotherapy, radiotherapy or high-dose chemotherapy and peripheral blood stem cell transplantation. It has been found that if lymphoma recurs after transplantation it often does so in sites involved prior to transplantation. Radiotherapy can prevent some of these relapses, and may improve the overall results of transplantation. Radiotherapy is often given only to bulky sites (i.e. more than 5-10 cm in size) of lymphoma following transplantation, but the optimal dose and area of radiotherapy is not known. It is possible that treating all the areas of lymphoma (including non-bulky areas) may be more effective. In this research study, radiotherapy was given to all the areas known to be affected by lymphoma (other than bone marrow) with the aims of assessing the ability of radiotherapy to reduce the risk of relapse following transplantation, and carefully evaluating the side effects of adding radiotherapy to transplantation.