Radiation safety and dialysate analysis in hemodialysis following Lu-177-PSMA-617 therapy: A case report

Purpose: We present a patient who is undergoing regular HD and received Lu-177-PSMA-617 treatment, regarding radiation safety issues including environmental radiation, exposure of medical personnel, and the radioactivity in the dialysate.

Methods: A 78 years old man with metastatic castration-resistant prostate cancer undergoing HD received 84.4 mCi (3.1 GBq) of Lu-177-PSMA-617. First HD during the 20th-24th hours after injection, and the second HD during 68th-71st hours. The environmental exposure rate and personnel exposure monitoring were measured. The dialysate was collected and sampled, and the activity was measured.

Results: During the first HD session, where dialysate was collected in the room, medical personnels received exposure of 3-19µSv. Dialysate was drained out in the second HD, and medical personnels received 2-4 µSv. The radiation exposure rates in the first HD were measured as follows: 3-4 µSv/hr bedside, 1.2-1.5 µSv/hr at 1 meter, and less than 0.3 µSv/hr at 4 meters. In the second HD, the rates were 2-3 µSv/hr bedside, 1.2-1.8 µSv/hr at 1 meter, and less than 0.3 µSv/hr at 4 meters.The dialysate had an activity of 6.88 mCi (0.25 GBq) in 120 liters of the first HD, while in the second HD, it had 2.13 mCi (0.08 GBq) in 90 liters.

Conclusion: For the medical personnel involving HD, the accumulative exposure doses were than 2-19 µSv after 20 hour of injection. The environmental exposure rate would drop to background at 4m away from the patient. The dialysate contained minimal amounts of Lu-177 radioactivity.