Dosimetry of Rhenium-186-Labeled Monoclonal Antibodies: Methods, Prediction from Technetium-99m-Labeled Antibodies and Results of Phase I Trials

Rhenium-186 is a beta-emitting radionuclide that has been studied for applications in radioimmunotherapy. Its 137 keV gamma photon is ideal for imaging the biodistribution of the immunoconjugates and for obtaining gamma camera data for estimation of dosimetry. Methods used for determining radiation absorbed dose are described. We have estimated absorbed dose to normal organs and tumors following administration of two different 186 Re-labeled immunoconjugates, intact NR-LU-10 antibody and the F(ab') 2 fragment of NR-CO-02. Tumor dose estimates in 46 patients varied over a wide range, 0.4-18.6 rads/mCi, but were similar in both studies