Incomplete yttirum-90 infusion and high residual radioactivity during radioembolization

Abstract

Purpose: Investigate the factors causing infusion stoppage and high residual radioactivity during the administration of yttrium-90 (Y90) microspheres. Materials and Methods: Retrospective analysis between July 2009 to June 2014 was performed of all radioembolization procedures at a single-institution including 310 Y90 infusions performed in 178 subjects with 1-4 infusions per subject. Treatment plans, slow flow infusion stoppage, and high residual radioactivity (Z20% not administered) were collected. Due to strong within-subject correlation, statistical analysis was performed only on the first observation per subject. The 3 most common cancer types were included. Pearson chi-square and Fisher's exact chi-square tests were used. Results: Stoppage due to slow flow occurred in 36/310 infusions of which 89% had Z20% residual radioactivity. Residual radioactivity of Z20% occurred in 34/310 infusions of which 94% had infusion stopped due to slow flow. There were 147 subjects for statistical analysis with hepatocellular (44%), colorectal (41%), and neuroendocrine (15%) neoplasms. Treatment was performed with resin microspheres in 76 of 147 subjects (51.7%) and the remaining with glass microspheres. High residual radioactivity of Z20% in 12 subjects occurred in the presence of slow flow infusion stoppage (po.0001) and only resin treatments (p¼.0005). Infusion stoppage due to slow flow occurred in 16 subjects of the resin microsphere type (po.0001). Initial results prompted a secondary multivariate analysis on resin treatments to predict slow flow and residual radioactivity. Conclusion: High residual radioactivity was significantly associated with slow flow stoppage and resin treatment.