Methods and apparatus for cryogenic treatment of a body cavity or lumen

A tissue treatment system, comprising:

• a thermal probe assembly having an elongate lumen, at least one infusion lumen positioned through or along the elongate lumen, and at least one delivery lumen in fluid communication with the infusion lumen, where the delivery lumen defines one or more openings therealong;
• a balloon defining an interior volume into which the thermal probe assembly is insertable, where the balloon is configured to conform to a tissue surface;
• a sheath translatable relative to the elongate lumen, wherein distal or proximal translation of the sheath selectively controls a number of the one or more openings which remain unobstructed and also correspondingly adjusts an expanded length of the balloon according to the number of one or more openings which are unobstructed;
• and,
• a reservoir having an ablative fluid in fluid communication with the thermal probe assembly and with the interior volume of the balloon, wherein introduction of the ablative fluid within the thermal probe passes the ablative fluid through the unobstructed one or more openings and into contact against the interior volume.