Centering brachytherapy catheter

A catheter for brachytherapy treatment of a body vessel from within a lumen thereof, the catheter comprising:

• an elongate flexible shaft having a distal end and a radiation source located within a distal treatment region;
• an actuator element having a distal end and being slidably disposed along the shaft;
• a monofilament wire-form mounted about the distal treatment region for radially centering the treatment region within the lumen, the wire-form having:
• i) a distal end coupled to the shaft adjacent the distal end thereof,
• ii) a proximal end coupled to the distal end of the actuator,
• iii) an expanded configuration preformed with multiple lobes arranged in a radially symmetrical staggered sequence along the distal treatment region, each lobe extending from adjacent the distal treatment region to an apex engageable with the lumen of the body vessel, and
• iv) a collapsed configuration formable compactly about the shaft by sliding the actuator proximally with respect to the shaft to draw apart the wire-form proximal and distal ends.