Apparatus and methods for administering treatment within a bodily duct of a patient

A treatment catheter for placement in a bodily duct of a patient, the treatment catheter comprising:

• an expandable structure,
• an elongate hollow shaft having a wall with a first through hole and a second through hole, the first through hole spaced axially apart from the second through hole, the elongate hollow shaft having a proximal end portion and a distal end portion, the expandable structure being disposed about the distal end portion of the elongate hollow shaft such that the first through hole resides beneath the expandable structure, the second through hole being located proximal to the expandable structure,
• a sleeve positioned along an outer surface of the elongate hollow shaft moveable between first and second axial positions to respectively permit and inhibit the flow of a treatment agent through the second through hole into the bodily duct,
• an elongate wire having a seal unit positioned within an inner lumen of the elongate hollow shaft, the seal unit positioned at least partially beneath the expandable structure and being moveable between first and second axial positions to respectively permit and inhibit the flow of an inflation medium between a cavity of the expandable structure and the inner lumen of the hollow shaft through the first through hole, the first axial position being located distal to the second axial position.