Abstract: A balloon catheter having a long shaft with an inflatable balloon connected to its distal end with a pressure source connected to the shaft at an invivo point which operates to inflate and deflate the balloon. The balloon catheter may be a fixed-wire type, an over-the-wire type, or an single-operator-exchange type catheter. The pressure source may include a piston and a chamber with an actuation member attached to the piston. The actuation member may be a solid rod or a hollow tube. In the case where the actuation member is a hollow tube, the tube may be used to introduce inflation fluid into the pressure source and the inflation lumen. A receptacle such as a reel or tubular hoop may be used to contain the actuation member when pulled proximally. A pressure sensor/gauge and a balloon sizing scale may be incorporated into the catheter assembly to assist the treating physician in monitoring the procedure.