Innovation of New Occlusion Devices for Cancers

Abstract

Liver cancer, a life-threatening disease, can be cured if found early. A common treatment for liver tumors that cannot be removed by surgery is hepatic artery embolization. It involves injecting small beads to block the blood flow towards cancer cells. In this paper, we propose the world's first nitinol spherical occlusion device, which can be deployed in the upstream of an artery to reduce the blood flow to the downstream cancer cells. Finite element models were developed to predict the device's mechanical integrity during manufacturing and deployment. Computational fluid dynamics were applied to simulate the device's clinical occlusion performance. Simulation results suggested that devices with a metal density of 14-27% would reduce the average blood flow rate by 30-50%. A conceptual prototype was first cut by pulsed-fiber optic laser, and a series of expansions and heat treatments were used to shape the device to its final geometry. Flow experiments were conducted for proof of concept, and results showed that the spherical occlusion device successfully reduced the flow as designed. The occlusion device with the metal density of 27% was able to reduce 44% of flow, which agreed well with the simulation results.

Effects of Tapered-Strut Design on Fatigue Life Enhancement of Peripheral Stents

“…To create the super-elastic effects, specific heat treatment process along with molding fixtures, were used after cutting to remove residual stresses and shape the device to the target size. Nitinol stents were progressively expanded by inserting rods of increasing sizes and heat-treated in a salt bath at an elevated temperature of 500 °C for 200 s. After each expansion, they were removed from the salt bath and quenched in cold water, ready for the next expansion [ 48 ].…”