Introduction to kidney dose-response for radionuclide therapy.

The proceedings of a MIRD-sponsored continuing medical education session entitled, “Kidney Dose–Response for Radionuclide Therapy,” held at the 50th Annual Meeting of the Society of Nuclear Medicine, in New Orleans in 2003, have been collected in this special section of Cancer Biotherapy & Radiopharmaceuticals. A few years ago, hematologic toxicity was the focus of concern in radionuclide therapy. The shift to concerns over renal toxicity reflects a number of developments in radionuclide therapy. Although the developments encompass, for example, peptidemediated receptor targeting,1 metabolic targeting using bone-seeking radionuclides,2 and engineered low-molecular-weight multivalent targeting,3 these can be generally described as a shift to constructs that have molecular weights substantially lower than the 150,000 daltons of intact antibodies. These smaller agents clear much more rapidly from the circulation than intact antibodies and, therefore, require substantially greater administered activities to deliver tumoricidal absorbed doses. The higher administered activities, the rapidclearance kinetics, and, most importantly, observations of delayed renal failure in a number of patients at kidney total absorbed doses not found to be toxic in external-beam radiotherapy experience2,4 have required a reexamination of: