Relatively Selective Beta Irradiation of Lymphatic Structures in the Dog Using Y⁹⁰-DTPA

In an attempt to provide relatively selective irradiation of tissues responsible for the homograft rejection response and to minimize exposure of other radiosensitive tissues, we developed a technic using internally administered Yttrium-90 chelated with DTPA (diethylene triamine-pentaacetic acid). Dogs given sublethal doses of Y⁹⁰-DTPA radiation had a benign clinical course, the only remarkable finding being a selective lymphopenia without depression of granulocytes, platelets, or reticulocytes. Dogs lethally irradiated with Y⁹⁰-DTPA showed depression of all formed blood elements, and severe depression of lymphocytes was most prominent. As the homograft rejection response appears to be a function of lymphatic tissues, the results obtained suggest the use of this procedure to prepare large mammals for homologous tissue transplantation.