Among other things, embodiments of devices (and parts thereof) are disclosed that can be used in treating Barretts esophagus. Embodiments may have a suction cavity or window portion having elongated planar floor and ramped end surfaces with suction holes on one or both end surfaces. Examples include one or more fluid injection needles and parts for controlling fluid injection rate based on the rate of needle withdrawal. Embodiments can include one or more injection needles and receiving holes, with the ability to allow injectate to flow into tissue before withdrawing the needle(s), and/or lockout mechanism to prevent resection of tissue by a cutting mechanism prior to injection of fluid. Methods for treatment are also disclosed, and can include inserting a needle completely through tissue, and injecting fluid into tissue while withdrawing the needle back through the tissue, and/or injecting fluid into tissue while moving the needle forward through tissue.
