One-year assessment of microbiological and particulate environnemental monitoring of equipment in a new radiopharmaceutical compounding unit

Objectives
When setting up our radiopharmaceutical compounding unit for PET imaging, we implemented environmental monitoring of the equipment for production in accordance with the updated Good Compounding Practices, to ensure their microbiological and particulate quality. The objective of this study was to analyze our monitoring results after one year of operation.

Method
Air and surface sampling were performed in-house. Three controlled environment equipment were monitored: shielded hot cell RS-75 (Class C) for radiosynthesis, shielded hot cell REP-75 (Class A) for aseptic dispensing and Biological Safety Cabinet (BSC) (Class A) for sterility tests. Sampling types: Passive air sampling (PAS), gloved fingertip sampling of right hand (GFS-R) and left hand (GFS-L) and swabs of remote handling tongs (RHT), surface sampling (SS: contact plates and swabs), active air sampling (AAS).
Data were recorded in real time using PHARMA MANAGER software. LMS Express software was used for particle counting. Twelve months of data (May 2024 to April 2025) were extracted and analyzed using Excel.

Results
Out of 195 radiosyntheses, the following non-compliances (NC) were observed:
RS-75 hot cell:
* SS: radiosynthesiser in RS1: 2NC/10, in RS2: 4/7 and workbenches in RS1/RS2: 0/17.
REP-75 hot cell:
* Gloves/tongs: GFS-F: 25 NC/195, GFS-R: 21/195, RHT: 2/195.
* SS: Ionisation chamber: 1 NC/39, workbenches: 2 NC/39, near the pass-through: 0/39, automated module for dispensing: 0/39.
* PAS: 0/195 et AAS: 0/9.
* Continuous particle counting: less than 3520 particles/m3 ≥ 0.5 µm and 20 ≥ 5 µm.
BSC: SS: 0 NC/132, PAS: 1/57, GFS: 14/61, all from the same operator (n=3).

Discussion-conclusion
Data analysis confirms the relevance of the implemented environmental monitoring program. The RS-75 hot cell complies with Class C requirements. In the REP-75, NC were frequently observed on GFS for gloves used during setup of the sterile kit (tubing, needles) on the module. However, RHT used for aseptic dispensing were rarely contaminated. Results for SS, AAS and PAS were satisfactory. The particle counting during aseptic operation confirm the compliance of the REP-75 with class A standards. For the GFS of BSC, NC were only observed for the newly trained operator, with a decreasing trend over time. Sterility test results for all radiopharmaceutical were compliant. Our results demonstrate that environmental classifications obtained are consistent with those required to ensure the quality of the produced radiopharmaceuticals. They also underscore the importance of routine environmental monitoring. Our results are in accordance to external quality control findings. Proper glove handling practices within the REP-75 enclosure will be reassessed.