Purpose: Recent advances in nuclear medicine therapy include the use of 177Lu-labeled compounds for peptide receptor radionuclide therapy (PRRT) of neuroendocrine tumors with 177Lu-Dotatate and metastatic prostate cancer with 177Lu-PSMA-617. Here we present the clinical workflow, quality management and radiation safety considerations for administration of 177Lu-PSMA-617 and compare to 177Lu-Dotatate.
Methods: 177Lu-PSMA-617 has been conducted at our institution under expanded access use and phase III clinical trials since fall of 2021. Prior to implementation of the 177Lu-PSMA-617 therapy protocols, our institution had been performing 177Lu-Dotatate routinely for over 2 years. The clinical workflow, quality management program, and radiation safety protocols developed at our institution for 177Lu-PSMA-617 therapy utilized our experience with 177Lu-Dotatate, and knowledge of the difference between 177Lu-PSMA-617 and 177Lu-Dotatate. Both workflows include pre-administration and residual assays of the drug vial, syringe and IV lines. Additionally, post-therapy exposure rate measurements and post-therapy imaging were performed for all patients receiving 177Lu-PSMA-617 and 177Lu-Dotatate at our institution.
Results: 177Lu-PSMA-617 workflow required consideration for several factors, including patient preparation prior to, during and after administration, pharmacokinetics and biological clearance rates. of 177Lu-PSMA-617 vs 177Lu-Dotatate. 8 treatments of 177Lu-PSMA-617 (4 patients) and 29 treatments of 177Lu-Dotatate (11 patients) were compared for variations in residual activity, patient exposure rates, and administered activity. Average administered activity was 189.2 +/-2.06mCi for 177Lu-PSMA-617 and 198.0 +/- 1.81mCi for 177Lu-Dotatate. Average residual activity was 1.97 +/- 1.13mCi for 177Lu-PSMA-617 and 3.07 +/- 0.61mCi 177Lu-Dotatate. Post-therapy exposure rates, measured at 1 meter from patients, were 2.43 +/- 0.37mR/hr 0.12mR/hr for 177Lu-PSMA-617 and 2.30 +/- 0.53mR/hr 177Lu-Dotatate.
Conclusion: Small but important changes should be implemented when 177Lu-Dotatate clinical workflow is adapted for 177Lu-PSMA-617 therapy. The differences in clinical workflow for 177Lu-PSMA-617 and 177Lu-Dotatate patients stem from a variety of factors. Similar radiation safety protocols can be utilized for both therapies.
Radiation Protection, Health Physics, Nuclear Medicine
IM/TH- Radiopharmaceutical Therapy: Safety, QA, and radiation protection