⁹⁰Y-Labeled Resin Microsphere Spills: A Pilot Study to Determine Efficient Cleanup Practices

⁹⁰Y-labeled resin microspheres (RMs) are selective internal radiation therapy agents encased in microscopic resin spheres and then suspended in water for injection. The ⁹⁰Y-RM package insert includes a recommended cleanup procedure for contamination spills. However, after a local hospital recently experienced a clinical incident, we explored the efficiency of the recommended cleanup procedure. The aim of this investigation was to demonstrate the effectiveness of different cleaning procedures and compare these with the recommended procedure. Methods: Controlled spills of ⁹⁰Y-RMs were placed in the middle of 10 independent 0.09 m² (1 ft²) tile sections of an existing vinyl tile floor. Each 0.09 m² (1 ft²) area was surrounded by absorbent pads and was further contained within 0.28 m² (3 ft²) 1.9-cm (¾ in)-thick plywood box enclosures. Three cleaning methods were implemented: damp paper towels (recommended procedure), adhesive paper, and a Swiffer wet mop (SWM). A calibrated Geiger counter was used to determine the maximum precleaning and maximum postcleaning exposure within the tile sections. Percentage exposure reduction was calculated for each cleaning trial, and because of the low sample size, nonparametric exact Kruskal-Wallis tests were used to determine differences in percentage exposure reduction among cleaning types. All statistical tests were conducted assuming a 5% chance of a type 1 error. Results: Both damp paper towels and the SWM were superior to adhesive paper (P = 0.0006 and P = 0.0005, respectively). There was no difference between damp paper towels and the SWM, nor did the variability of the cleanup methods differ (P = 0.6826 and P = 0.2501, respectively). Conclusion: Damp paper towels and the SWM decontaminated the controlled spills equally. This finding indicates that the SWM can effectively clean up ⁹⁰Y contamination.