| 摘要 |
<p>A catheter or the like is steerable through cavities within a body and aimable toward organ or tissue within the body. The catheter includes an elongated tubular member having a distal end for insertion into the body and a temperature-activated memory element in the distal end of the hollow tubular member. The memory element has an initial shape and moves to assume a predetermined shape when heated to a predetermined temperature. A control system is provided for selectively heating the memory element to the predetermined temperature so that the memory element is moved in a first direction to deflect the distal end of the tubular member and thereby steer or aim the catheter within the body. A spring assembly is provided for yieldably urging the memory element in an opposite second direction to establish the initial shape and also to aid in returning the memory element to its initial shape when the temperature of the memory element is less than the predetermined temperature. The spring assembly includes a core member for supporting the memory element and a resilient member. Both the core member and resilient member are preformed to assume curved shapes and both move to assume a shape other than the preformed curved shapes in response to movements of the memory element in the first direction.</p> |
