A catheter capable of irradiating blood vessel walls to inhibit restenosis after angioplasty. Catheters are capable of simultaneous irradiation, angioplasty, and in some devices, drug infusion. Preferred catheters include a helical perfusion balloon having strand windings spaced apart when inflated and defining a perfusion lumen within. A tubular sheath over the helical strands and distal shaft region is used in some embodiments and defines an outer wall for the perfusion lumen. A spiral, inter-strand space is defined between the sheath outer wall and the blood vessel inner wall, providing a confined volume for controlled delivery of drugs to the vessel wall in conjunction with irradiation. A device having a radiation wire, distally closed-end tube is provided. A device having a radiation wire open ended tube terminating proximally of the perfusion lumen is also provided.
