Yttrium-90-labeled human macroaggregated albumin for internal radiotherapy : Combined use with DTPA

Abstract The aim of this study was to investigate the possibility of yttrium-90-labeled human macroaggregated albumin ( 90 Y-MAA) as an internal radiotherapeutic agent for whole-lung irradiation in combination with diethylenetriamine pentaacetic acid (DTPA). The influence of trisodium calcium DTPA (CaNa 3 DTPA) on the radioactivity of 90 Y-MAA in serum was investigated in vitro. The effect of CaNa 3 DTPA on the biodistribution of radioactivity in normal mice intraveneously injected with 90 Y-MAA was examined. CaNa 3 DTPA could deprive in vitro radioactivity of 90 Y-MAA in 48-h incubation. Most of the radioactivity (>90% injected dose per lung) was observed at murine lung after injection of 90 Y-MAA. Pulmonary radioactivity was cleared within 72 h postinjection, whereas the radioactivities in the bone, liver, kidneys, and spleen increased with a peak at 48 h. CaNa 3 DTPA-treatment reduced the in vivo radioactivities in bone, liver, and kidneys without influence on the radioactivity of lung. In conclusion, combined use of CaNa 3 DTPA enables 90 Y-MAA to be used as a radiopharmaceutical for internal irradiation against whole lung.