Methods of imaging a breast comprising acquiring a sequence of image data sets having differing exposure parameters; and combining the image data sets into a mammography image having greater dynamic range than the dynamic range of any single component image data set. The positioning device has a base and a superstructure with an adjustable platform for mounting a model of a patient’s teeth and a free-floating composite register assembly. The first screw is screwed into the first connecting through hole and a first panel threaded hole on the first side for fastening the first connecting portion and the first side.