A transfer device usable in a system for intraluminal treatment of a selected site in a body of a patient in which the transfer device comprises an integral pump for pressurizing and circulating fluid through a fluid path defined by the transfer device and associated catheter. A removable fluid cartridge is provided including a reservoir from which fluid is drawn by the pump and into which fluid is returned after being circulated through the fluid path. The pump may be a peristaltic pump and the fluid cartridge may include an elongated fluid pick-up having an inlet through which fluid is introduced into the transfer device. The fluid pick-up is sized in length so that the inlet is always submerged in the fluid regardless of the orientation of the transfer device.