Abstract: Methods and systems for deployment of a detachable, inflatable balloon at a target site in vivo are disclosed. In one aspect of the invention, the method involves providing a holder; passing a protective sheath through the lumen of the holder; passing a positioning element through the lumen of the sheath; advancing the positioning element to the target site in vivo; withdrawing the positioning element while keeping the sheath fixed relative to the holder; passing a detachable, inflatable balloon coupled to a distal end of a delivery device through the sheath; withdrawing the sheath into a retractor disposed at proximal end of the delivery device such that the delivery device remains fixed relative to the holder and the balloon is exposed to the target site in vivo; and inflating and detaching the balloon.