A catheterization system for treatment of a condition within a blood vessel is provided with a catheter, a balloon immediately adjacent to the distal end of the catheter, an inflation device for expanding the balloon, and a fluid injection device for injecting a treatment fluid through the central lumen of the catheter and out of the aperture at the distal end of the catheter into the treatment area. The system may include an RF wire, a hollow needle wire, a dissection tool, or a laser wire insertable through the central lumen of the catheter and selectively operable adjacent the proximal end of the catheter to apply treatment within the blood vessel.