3:27 PM Abstract No. 25 Iodinated coating of decayed Y-90 microspheres to improve radiopacity with cone-beam computed tomography

Abstract

To envelope SIR-Spheres (SS) with a chitosan/iodine shell in order to display greater contrast enhancement compared to non-coated control SS with cone-beam CT. Centrifuge 1000μL of radioactively inactive SS at 10,000 RPM for 10 minutes and remove excess water. Combine 7mL of Omnipaque (Op) solution (2% acetic acid, 3 mg/mL chitosan) with the pelleted SS and place on a shaker plate for 30 minutes. While shaking, add 7mL of 10 mg/mL TPP (in 100% Op) dropwise over 1 minute, and continue to shake for 30 minutes. Wash the sample by centrifuging at 14,000 RPM for 10 min then resuspending in diH2O. Continue these spin/wash cycles for a total of 3 washes. Remove 25μL of sample and place on a scanning electron microscope (SEM) stub for SEM and Elemental Dispersive X-Ray Spectroscopy (EDX) analysis. Transfer the remaining washed sample to a 1.5mL centrifuge tube for cone-beam CT assessment. In order to add additional coatings, the above steps were repeated. Cone beam CT imaging showed an increase in contrast resolution of double and triple coated SS when compared to control SS. Better contrast resolution was seen with triple coated SS when compared to double coated SS. SEM images of control SS, singe coated SS, double coated SS, and triple coated SS showed progressive layering of chitosan/Op coatings with each additional coating attempt. EDX elemental analysis results show a stepwise increase in iodine content when looking at control SS, single coated SS, double coated SS, and triple coated SS, with average iodine contents of 0%, 33.4%, 42.8%, and 63.0% respectively. The ability to intraoperatively assess SIRT dosage delivery would allow localization of treated and untreated regions. With this knowledge, other interventions can be applied to ensure a more efficacious treatment plan. In this study we were able to apply significant amounts of radiopaque iodine to the surface of SS. With the utilization of SEM, EDX, and cone-beam CT, we confirmed that we (1) successfully enveloped SS in crosslinked chitosan, (2) successfully entrapped iodinated molecules within this chitosan shell, and (3) successfully demonstrated visibility with cone-beam CT of SS with the iodinated shell.