Renal and Intestinal Excretion of ⁹⁰Y and ¹⁶⁶Ho After Transarterial Radioembolization of Liver Tumors.

Abstract

<b>OBJECTIVE.</b> The aim of this study was to evaluate the amount of free radioactivity in renal and intestinal excretions during the first 48 hours after transarterial radioembolization (TARE) procedures on the liver. <b>SUBJECTS AND METHODS.</b> Urinary, intestinal, and biliary excretions of patients who underwent TARE with three different types of microspheres were collected during a postinterventional period of 48 hours (divided into two 24-hour intervals). Radioactivity measurements were performed. The detected amounts of activity were correlated to clinical and procedural characteristics, times of excretion, and microsphere types. <b>RESULTS.</b> Twenty-four patients were evaluated, 10 treated with ⁹⁰Y-glass, 10 with ⁹⁰Y-resin, and four with ¹⁶⁶Ho-poly-L-lactic acid (PLLA) microspheres. Activity excretion occurred in all cases. The highest total excretion proportions of the injected activities were 0.011% for ⁹⁰Y-glass, 0.119% for ⁹⁰Y-resin, and 0.005% for ¹⁶⁶Ho-PLLA microspheres. Intestinal excretion was markedly less than renal excretion (<i>p</i> < 0.001). Excretion after TARE with ⁹⁰Y-resin was statistically significantly higher than with ⁹⁰Y-glass or ¹⁶⁶Ho-PLLA micro-spheres (<i>p</i> = 0.002). For each microsphere type, the excreted activity was independent of the activity of the injected microspheres. <b>CONCLUSION.</b> Renal and intestinal excretion of radioactivity after TARE is low but not negligible. The radiation risk for individuals interacting with patients can be minimized if contact with urine and bile is avoided, particularly during the first 24 hours after the procedure.