Abstract: Methods of selectively treating linear elastic materials to produce localized areas of superelasticity and/or shape-memory are disclosed. In an illustrative method, a linear elastic workpiece may be formed into a particular shape by cold-forming or other low-temperature process, and incorporated into a medical device such as an embolic protection filter, vena cava filter, stent or guidewire. A heat source may be used to apply thermal energy to selective areas of the workpiece, imparting superelasticity to the material.

Abstract: A radiation delivery system including a catheter shaft having a distal head. A fixed or removable radiation source is disposed adjacent the distal head. The distal head includes a radiation shield having a window and an ultrasonic transducer. The ultrasonic transducer provides a signal indicative of relative position, tissue geometry and/or tissue characteristics, which may be utilized to determine the appropriate placement of the radiation shield window such that only selected portions of the treatment site are exposed to radiation. The radiation delivery system may include a drive means coupled to the distal head to facilitate rotation thereof. The rotatable head may be rotated at a constant velocity or at a velocity which varies as a function of the signal (e.g., distance from the vascular wall and/or stenotic thickness).