The invention relates to an apparatus for photodynamic therapy and/or for destroying or reducing microorganisms, comprising an irradiation unit having at least one light source, by means of which a photosensitizer applied to a wound area to be treated is activated by way of irradiation, further comprising a camera for recording images of the wound, which is disposed in the irradiation unit, and a positioning unit, by means of which the irradiation unit can be oriented with respect to the wound area. The invention further relates to a method for operating such an apparatus. On a display for the images is a grid with visual indicia distinguishing fields to be irradiated by means of the light sources.
