POSITIONING SYSTEM FOR CATHETER TIPS BASED ON AN ACTIVE MICROVALVE SYSTEM

A positioning system for orienting and fixing the tip of a catheter in side a vessel is presented. A microvalve system with 2.5 mm outer diam eter steers the positioning mechanism by varying the size of inflatabl e balloons mounted on the tip's side, In the presented prototype a las er beam, passed through the system with an optical fiber, can be posit ioned with two lateral and one angular degree of freedom inside a lume n with 3-4 mm inner diameter. The normally open valves are actuated el ectro-thermo-pneumatically featuring freely suspended resistive heater s. 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 perform ance.