A system for aspirating thrombus comprising: an aspiration catheter having a supply lumen and an aspiration lumen, the supply lumen having a distal end, the aspiration lumen configured to couple to a vacuum source and having an interior wall surface, and an open distal end; an orifice at or near the distal end of the supply lumen, the orifice located within the aspiration lumen, and proximal to a most proximal portion of the open distal end of the aspiration lumen, wherein the orifice is configured to create a fluid jet when pressurized fluid is pumped through the supply lumen such that the fluid jet impinges on the interior wall surface of the aspiration lumen when a distal end of the aspiration catheter is immersed within an aqueous environment; and a tubing set having a first conduit configured to couple the supply lumen of the aspiration catheter to a fluid source, and a pump component moveably engaged within the first conduit and configured to detachably couple to a drive unit (200, 400), such that motion from the drive unit is transferred to the pump component such that resultant motion of the pump component causes fluid from the fluid source to be injected through the supply lumen of the aspiration catheter, and through the orifice into the aspiration lumen, wherein the pump component comprises a piston having an inner bore having a one-way valve, the piston slidably contained within a supply cylinder and an injection cylinder, the piston configured to actuate into the supply cylinder while actuating out of the injection cylinder, thus causing the injection cylinder to increase its volume of fluid supplied from the fluid source and through the inner bore of the piston, and wherein the piston is further configured to actuate into the injection cylinder while actuating out of the supply cylinder, thus causing the injection cylinder to decrease its volume by injecting fluid supplied from the fluid source into the supply lumen of the aspiration catheter. an aspiration catheter having a supply lumen and an aspiration lumen, the supply lumen having a distal end, the aspiration lumen configured to couple to a vacuum source and having an interior wall surface, and an open distal end; an orifice at or near the distal end of the supply lumen, the orifice located within the aspiration lumen, and proximal to a most proximal portion of the open distal end of the aspiration lumen, wherein the orifice is configured to create a fluid jet when pressurized fluid is pumped through the supply lumen such that the fluid jet impinges on the interior wall surface of the aspiration lumen when a distal end of the aspiration catheter is immersed within an aqueous environment; and a tubing set having a first conduit configured to couple the supply lumen of the aspiration catheter to a fluid source, and a pump component moveably engaged within the first conduit and configured to detachably couple to a drive unit (200, 400), such that motion from the drive unit is transferred to the pump component such that resultant motion of the pump component causes fluid from the fluid source to be injected through the supply lumen of the aspiration catheter, and through the orifice into the aspiration lumen, wherein the pump component comprises a piston having an inner bore having a one-way valve, the piston slidably contained within a supply cylinder and an injection cylinder, the piston configured to actuate into the supply cylinder while actuating out of the injection cylinder, thus causing the injection cylinder to increase its volume of fluid supplied from the fluid source and through the inner bore of the piston, and wherein the piston is further configured to actuate into the injection cylinder while actuating out of the supply cylinder, thus causing the injection cylinder to decrease its volume by injecting fluid supplied from the fluid source into the supply lumen of the aspiration catheter.