Positioning system for catheter tips based on an active microvalve system

Abstract

A positioning system for orienting and fixing the tip of a catheter inside a vessel is presented. A microvalve system with 2.5 mm outer diameter steers the positioning mechanism by varying the size of inflatable balloons mounted on the tip's side. In the presented prototype a laser beam, passed through the system with an optical fiber, can be positioned with two lateral and one angular degree of freedom inside a lumen with 3-4 mm inner diameter. The normally open valves are actuated electro-thermo-pneumatically featuring freely suspended resistive heaters. The system is designed as a low-pressure device requiring a supply pressure in the range of 100 to 200 hPa and a power input of 20 to 40 mW. Thus the positioning can occur without exerting excessive force on the vessel's wall. This paper covers the system design, the assembly of the components and the in vitro demonstration of the system performance.