A radiofrequency balloon catheter system to heat and dilate a stenosis site while protecting an intima. The system includes an elastic balloon with its anterior neck covering an inner tube, and the anterior neck has a distal portion fixed to the inner tube and a proximal portion contacted by the inner tube to thereby define a check valve. When an in-balloon solution is suctioned to turn the inside pressure of the balloon to negative, the check valve is closed to deflate the balloon. When the in-balloon solution is injected into the balloon to turn the inside pressure of the balloon to positive, the balloon is inflated and the check valve is opened, thus discharging the solution to the outside via small holes bored through a specific portion of the inner tube that serves as a valve seat.
