A system for intravascular treatment, comprising: a catheter having an elongate axis defining a hypotube lumen configured for receiving a hypotube, the hypotube lumen terminating at a distal opening in an external side wall of the catheter; and a hypotube slidably received within the hypotube lumen, the hypotube having a sharpened distal tip and being configured in relation to the catheter to have a retracted condition in which the distal tip is contained entirely within the hypotube lumen, and an advanced condition in which the distal tip protrudes from the distal opening; characterized in that said system further comprises: a plurality of positioning lumens extending through the catheter; and a plurality of positioning wires each extending through an associated positioning lumen for at least a portion of the length of the positioning wire, and each positioning wire emerging from its associated positioning lumen to extend along the catheter over a first distance; wherein each portion of each positioning wire extending along the catheter over said first distance is configured in relation to the catheter to have an unexpanded condition for intravascular delivery in which each positioning wire is collapsed against an external wall of the catheter, and an expanded condition for positioning the catheter within a vessel in which each positioning wire is flexed away from the catheter along an associated imaginary plane (P, Q, R, S) extending radially away from the elongate axis, wherein all imaginary radial planes (P, Q, R, S) occupied by a flexed positioning wire are included within an angular arc (β) about the elongate axis of not more than 180 degrees; and wherein the flexed positioning wires in the expanded condition are located in relation to the catheter so that the angular arc (β) has a center that is substantially diametrically opposite the position of the distal opening. a catheter having an elongate axis defining a hypotube lumen configured for receiving a hypotube, the hypotube lumen terminating at a distal opening in an external side wall of the catheter; and a hypotube slidably received within the hypotube lumen, the hypotube having a sharpened distal tip and being configured in relation to the catheter to have a retracted condition in which the distal tip is contained entirely within the hypotube lumen, and an advanced condition in which the distal tip protrudes from the distal opening; characterized in that said system further comprises: a plurality of positioning lumens extending through the catheter; and a plurality of positioning wires each extending through an associated positioning lumen for at least a portion of the length of the positioning wire, and each positioning wire emerging from its associated positioning lumen to extend along the catheter over a first distance; wherein each portion of each positioning wire extending along the catheter over said first distance is configured in relation to the catheter to have an unexpanded condition for intravascular delivery in which each positioning wire is collapsed against an external wall of the catheter, and an expanded condition for positioning the catheter within a vessel in which each positioning wire is flexed away from the catheter along an associated imaginary plane (P, Q, R, S) extending radially away from the elongate axis, wherein all imaginary radial planes (P, Q, R, S) occupied by a flexed positioning wire are included within an angular arc (β) about the elongate axis of not more than 180 degrees; and wherein the flexed positioning wires in the expanded condition are located in relation to the catheter so that the angular arc (β) has a center that is substantially diametrically opposite the position of the distal opening. a plurality of positioning lumens extending through the catheter; and a plurality of positioning wires each extending through an associated positioning lumen for at least a portion of the length of the positioning wire, and each positioning wire emerging from its associated positioning lumen to extend along the catheter over a first distance; wherein each portion of each positioning wire extending along the catheter over said first distance is configured in relation to the catheter to have an unexpanded condition for intravascular delivery in which each positioning wire is collapsed against an external wall of the catheter, and an expanded condition for positioning the catheter within a vessel in which each positioning wire is flexed away from the catheter along an associated imaginary plane (P, Q, R, S) extending radially away from the elongate axis, wherein all imaginary radial planes (P, Q, R, S) occupied by a flexed positioning wire are included within an angular arc (β) about the elongate axis of not more than 180 degrees; and wherein the flexed positioning wires in the expanded condition are located in relation to the catheter so that the angular arc (β) has a center that is substantially diametrically opposite the position of the distal opening.