A method for delivering electromagnetic radiation onto tissue to be ‘treated with the radiation includes delivering the radiation onto the tissue in a treatment-spot having a polygonal shape such as a rectangle or a hexagon. The polygonal shape is selected such that a region of the tissue to be treated’ can be completely covered by a plurality of such shapes essentially without overlapping the shapes. The radiation to be delivered is passed through a lightguide having a cross-section of the polygonal shape. Radiation exiting the lightguide is projected onto the tissue via a plurality of optical elements to provide the treatment-spot.