The method involves filling exposure bag with supplement to less than thirty percent volume of the maximum volume of the exposure bag for photodynamic treatment or irradiation with ultra-violet light. The exposure bag is moved during the photo-dynamic treatment or the irradiation with ultravoilet light, so that contents of the exposure bag are rolled and zones of changing layer thicknesses are formed by the movement. The photoactive substance is a phenotiazines dyestuff, particularly thionin, methylene blue, phthalocyanine, phorphyrin and toluidine blue.
