A balloon catheter for insertion in a vessel includes a catheter shaft (24) and an inflatable balloon (12) attached to the catheter shaft； the balloon including a working surface having a midpoint (B) in an inflated condition； at least one first radiopaque marker (39) correspoonding to the location of at least one end of the working surface in the inflated state； at least one secondradiopaque marking (30) corresponding to the location of at the midpoint of the working surface in the inflated condition.
