Departments of Radiology and Radiation Oncology, University of Washington, Seattle, W A
*Correspondence to: Joseph Rajendran, M.D., Division of Nuclear Medicine, Box 356113, University of Washington, Seattle, WA 98195, Phone: 206 598 4240
A magic-bullet approach has long been the goal in managing cancer. Availability of monoclonal antibodies, engineered antibody fragments as well as easy availability of isotopes has rekindled the waning interest in radioimmunotherapy. The aim is to deliver the maximum radiation absorbed dose possible to the tumor while sparing the normal tissues from serious toxicities. Delivery of optimal amount of radioactivity to the tumor is challenging and is governed by several factors. RIT generally uses particle emitters (beta and alpha) but the presence of gamma emission is advantageous for performing imaging for dosimetry. Accurate estimation of radiation absorbed dose to the tumor is a vital part of treatment planning. Although radioimmunotherapy has been tried in many solid tumors, it has shown greater success in non-Hodgkin‘s lymphoma, due largely to abundant expression of antigens in B cells that can be easily targeted as well as the inherent radiosensitivity of lymphoid tissues. Commercial availability of non-myeloablative agents for NHL has brought new roles for nuclear medicine physicians. However, in order to consolidate the results of such therapy, high dose myeloablative treatment, which requires bone marrow rescue, has been successfully introduced.
