Apparatus and methods for administering treatment within a bodily duct of a patient are disclosed. According to one implementation a treatment catheter having an expandable structure disposed at an end thereof is provided that includes an elongate hollow shaft having a one or more first through holes and one or more second through holes spaced axial apart, the one or more first through holes residing beneath the expandable structure. A sleeve positioned along an outer surface of the hollow shaft is moveable between first and second axial positions to respectively permit or inhibit the flow ofa treatment agent through the one or more second through holes into the bodily duct. An elongate wire having a seal unit is positioned within an inner lumen of the hollow shaft. The seal unit is moveable between first and second axial positions to respectively permit or inhibit the flow of an inflation medium between a cavity of the expandable structure and the inner lumen of the hollow shaft through the one or more first through holes.
