Yttrium-90 SIR Sphere Spills: A Pilot Study to Determine Efficient Clean-up Practices

: Rationale: Yttrium-90 (90Y) SIR-Spheres are Selective Internal Radiation Therapy (SIRT) agents encased in microscopic resin spheres, then suspended in water for injection. SIR-Spheres (SIRTeX) include recommended clean-up procedures for contamination spills. However, after a recent clinical incident, the efficiency of recommended clean-up procedures was explored. The aim of this investigation is to demonstrate the effectiveness of different cleaning procedures and compare these to the recommended procedure. Methods: Controlled spills of 90Y SIR-Spheres were placed in the middle of 10 independent one ft2 tile sections of an existing vinyl tile floor. Each one ft2 area was surrounded by absorbent pads, and further contained within 3 ft2 ¾ inch thick plywood box enclosures. Three cleaning methods were implemented: damp paper towel (recommended procedure), adhesive paper, and a Swiffer™ (Procter and Gamble) wet mop (SWM). A calibrated Geiger counter was used to determine the maximum pre-cleaning and maximum post-cleaning exposure within the tile sections. Percent exposure reduction was calculated for each cleaning trial, and due to low sample size, non-parametric exact Kruskal-Wallis tests were used to determine differences in percent exposure reduction among cleaning types. All statistical tests were conducted assuming a 5% chance of a type 1 error, using SAS 9.4 (Cary NC). Results: Both the damp paper towel and SWM methods were superior to the adhesive paper method. (P = 0.0006, P = 0.0005 respectively). There was no difference between the damp paper towel and SWM methods, nor was the variability of the clean-up methods different. (P = 0.6826, P = 0.2501 respectively) Conclusion: The damp paper towel and SWM methods decontaminated the controlled spills equally. This indicates that the SWM can effectively clean up 90Y contamination.