Ultrasound characterization of slow precipitating implants for vascular occlusion

A current standard clinical treatment for liver cancer patients is drug eluting bead trans-arterial chemoembolization (DEB-TACE), where doxorubicin-loaded microparticles are injected via catheter into the hepatic artery that feeds the tumor. Due to the large bead diameter (~200μm), occlusion occurs far away from the tumor creating a hypoxic region affecting both healthy and cancerous tissue. As an alternative to beads, we have developed a slow precipitating occlusion solution (sPI) which will be capable of continuous, deeper occlusion. Because the precipitation rate of the solution is critical to the penetration depth, and to the eventual success of this application, this study tested the feasibility of controlling solution precipitation by increasing polymer to solvent ratios and evaluating the occlusion distance using ultrasound imaging in a tissue-mimicking flow phantom.