Lutetium-177 on ambulatory basis, a radiation safety approach

Abstract

The overarching objective of the study is to assess the applicability of 177Lu-PSMA-617 for the treatment of metastatic castration-resistant prostate cancer and 177Lu-DOTATATE for neuroendocrine tumors in an ambulatory context. To this end, the study determines the effective half-life of these two commercial versions of the isotope during the first 24 h of treatment. These measurements are then used to estimate the external dose absorbed by caregivers and the amount of 177Lu to be discharged into the sewage network in the case of ambulatory treatment. The study utilized live dosimetry measurements of 18 hospitalized patients during 24 h. The detector was placed above the bed and the data was collected every 5 min. Data was processed, visualized, and analyzed using several Python libraries. 177Lu-PSMA and 177Lu-DOTATATE average effective half-life during hospitalization was 6.42 ± 0.14 h and 4.25 ± 0.09 h, respectively. Predicted external dose for caregivers was estimated to be less than 0.1 mSv/cycle. Around 0.45 GBq of 177Lu would be discharged into the sewage network in case of 177Lu-DOTATATE and 0.3 GBq in case of 177Lu-PSMA. From a radiological safety point of view, it is safe to treat with 177Lu on an ambulatory basis. However, in future studies, the amount of 177Lu discharged into wastewater should be considered.