Catheter and system for controlling same

摘要

The present invention describes a system for controlling a thin flexible thermoplastic catheter. The system includes a plurality of shape memory alloy filaments attached to the distal end of the catheter, each filament having a phase and a temperature; a means for receiving a strain value for at least one of the filaments; a means for determining the phase change that will results in the strain value, whereby the phase change is dependent on the temperature and the temperature is dependent on a voltage; and a means for setting the voltage in each filament thereby resulting in movement of the catheter. In addition, a three-degrees of freedom force sensor measures the magnitude and direction of the force exerted on the tip of the catheter. The catheter can be autonomously guided or it can be interfaced to a haptic device. The catheter can also be fitted with microtools.

主权项

1. A system for controlling a thin flexible thermoplastic catheter comprising:
a plurality of shape memory alloy filaments attached to the distal end of the catheter, each filament having a solid-state phase and a temperature, wherein the catheter is of a size configured for insertion into the blood vessel; a means for receiving a strain value for at least one of the filaments; a means for determining a solid-state phase change that will result in the strain value, whereby the solid-state phase change is dependent on the temperature and the temperature is dependent on a voltage; and a means for setting the voltage in each filament thereby resulting in bending of the catheter in three dimensional space, wherein the temperature is determined using a formula given byT.=1mcp[V2R-hA⁡(T-Ta)]where m is the mass per unit length, cp is the specific heat capacity, V is the voltage applied across the shape memory alloy filament, R is the resistance per unit length, h is the coefficient of convection, A=πd is the circumferential area of cooling, d is the diameter of the filament, T is the temperature and Ta is the ambient temperature.