A method and apparatus for treating atrial tissue include positioning a lesion formation tool against the atrial surface. The carbonated vegetable oils advantageously may be used for producing nonisocyanate polyurethane materials. The partial light-transmitting region of the photomask has a plurality of first holes that are transmittable of the exposure light and a plurality of second holes that are arranged to surround the plurality of first holes and transmittable of the exposure light, and the area of each second hole is larger than the area of each first hole. A detector receives the returning probe radiation, and forms an image of the region that corresponds to a resolution better than pump and probe Abbe limits of the optical system. Members may have an other members inclusive list or other members exclusive list to assist in facilitating interactions.