Abstract: A method and apparatus for ablation of a layer of tissue is achieved by providing first and second bodies on opposed sides of the tissue. The first body includes a first ablation member and a source of magnetic force adjacent one side of the tissue. The second body includes a second ablation member and a magnetically attractive element responsive to the magnetic force adjacent the other side of the tissue. The magnetic attraction between the source and the attractive element is adapted to align the first and second bodies in opposed relationship on the opposed sides of the tissue. One of the first and second bodies may include at least one expandible member for controlling the magnetic attraction between the bodies.