A catheter-based medical device including controlled refrigerant dispersion is disclosed. The device includes a fluid injection tube that carries refrigerant from a coolant supply to the distal portion of the device. A fluid dispersion unit is disposed on the distal end of the fluid tube to control the angle of distribution for refrigerant that is expelled from the fluid injection tube. Controlling the angle of distribution for the refrigerant facilitates dispersion of the fluid in a predetermined spray pattern. The disclosure further relates to cryoablation treatment systems incorporating such a catheter, and to cryoablation treatment methods for tissue treatment to address various conditions suitably treatable with cryoablation.