2247 - A Single-Center Quality Assurance Study of Exposure to Staff from Lu-177 based Radiopharmaceutical Procedures in Tertiary Care Radiation Oncology Department

Purpose/Objective(s):

In 2022, our Radiation Oncology (RO) Department implemented a revised radiopharmaceutical quality management program to incorporate lutetium Lu 177 vipivotide tetraxetan (Pluvicto) therapy for metastatic prostate cancer. This study evaluates occupational radiation exposure to staff involved in Pluvicto administration and assess the efficacy of our radiation safety protocol. We hypothesized that variations might exist in radiation exposure among cross-covering staff due to differences in role, case complexity, and potential minor incidents.

Materials/Methods:

All departmental radiation workers routinely wear monthly optically stimulated luminescence (OSL) personnel badges and thermo-luminescent (TL) ring dosimeters. For this study, staff directly involved in each Pluvicto administration (radiation oncologist, therapeutic medical physicist, nurse, and medical assistant) wore additional OSL badges and TL ring dosimeters specific to the procedure. The supplemental dosimeters were collected after each Pluvicto administration and processed with the standard monthly batch by an external vendor. The International Commission on Radiological Protection (ICRP) recommended limits for occupational radiation exposure (20 mSv annually averaged over five years, with no single year exceeding 50 mSv) served as a reference. Dosimetry data were analyzed to determine individual and procedural radiation exposure levels. The roles of the staff members were as follows: the physician and physicist retrieved the radiopharmaceutical from the Nuclear Medicine Department, while nursing staff managed patient care from injection through escort from the RO department (after meeting physicist-validated release criteria).

Results:

Supplemental dosimeters were analyzed for six Pluvicto administrations. For all staff members involved, the additional dosimeter readings were below the minimum reportable dose (1 mrem for OSL badges, 10 mrem for TL rings), with consistency regardless of staff role. The minimal variation in dosimeter readings across procedures and staff suggests reproducible compliance to the radiation safety protocol.

Conclusion:

Our findings demonstrate a minimal level of additional radiation exposure to staff administering Lu-177 Pluvicto to prostate cancer patients when adhering to departmental standard operating procedures (SOPs). Based on these results, cumulative exposure from multiple administrations is anticipated to remain well below the annual ICRP limit of 50 mSv (5000 mrem). Future research will involve a multi-institutional study to assess inter-institutional variations in practice and a longitudinal study to evaluate cumulative radiation exposure over time.