Measurement of Airborne Radioactivity in the Inpatient Room after Administering [177Lu]Lu-PSMA-617 to Humans

Abstract

[177Lu]Lu-PSMA-617 is a radioisotope used in nuclear medicine. It is necessary to take appropriate measures to limit its exposure and ensures its airborne concentrations do not exceed legally permitted levels. Therefore, the purpose of this study was to measure the airborne radioactivity concentration in the inpatient room after administering [177Lu]Lu-PSMA-617 to humans. Three males with advanced prostate-specific membrane antigen (PSMA)-positive metastatic castration resistant prostate cancer were intravenously administered [177Lu]Lu-PSMA-617 (7.4 GBq ± 10%) in an inpatient room, and the airborne radioactivity concentrations were measured at two locations in the room (in the center of the room and at the bedside) using a filter collection method. After administration of [177Lu]Lu-PSMA-617, the airborne radioactivity concentrations measured were below the limit of detection (1.1 × 10-6 Bq/cm3 or 9.5 × 10-7 Bq/cm3) in all three humans, and all concentrations were consistently below the standard value of 1/10,000 of 2 × 10-2 Bq/cm3, the legal airborne concentration limit of 177Lu. The results of this study confirmed that the airborne concentration of [177Lu]Lu-PSMA-617 after administration to humans was below the legally permitted level.