A method for using CO2 as a contrast material in medical imaging procedures is disclosed. The method includes providing a source of pressurized CO2. The step of providing includes connecting the source of pressurized CO2 to a compressed gas unit for controlling delivery of the CO2. The method also includes regulating pressure of the CO2 delivered by the compressed gas unit, transmitting the pressurized CO2 from the compressed gas unit to a control valve assembly for delivery to a patient in controlled dosages, and sequentially processing the CO2 with the control valve assembly and delivering the CO2 to the patient as a contrast media.
