Abstract: An inflation system for pressurization and depressurization of a balloon catheter. The inflation system includes a syringe, including a syringe barrel, a plunger with expandable thread, a handle with cam, a syringe end cap, and a digital pressure gauge. The syringe is structured such that part of the syringe barrel has an internal thread which engages the expandable threads of the plunger. In the disengaged mode, the plunger slides freely within the syringe barrel allowing for rapid motion to purge, pressurize, or depressurize the inflation system. Once pressure reaches a predetermined level in the system, the cam on the handle causes the threads to automatically lock against the syringe barrel, and continued pressurization or depressurization is accomplished by the rotation of the plunger handle with respect to the syringe barrel. One advantage of the inflation system is that only one step is necessary for locking the syringe for controlled pressurization and depressurization.