The present application is directed to a phototherapy system for treating a treatment region having a treatment surface. The phototherapy system comprises an optical device. The opiicai device includes a light source generating source Sight, an emission surface emitting emitted light, and a sheet waveguide. The light source is coupled to direct the source light into the sheet waveguide. The sheet waveguide has a plurality of light extraction features that direct light out of the sheet waveguide. The emitted light has a wavelength to activate a photoactive compound the emitted light has a therapeutic radiant emittance. The phototherapy system may comprise a feedback component that measures the light intensity near the treatment surface and provide feedback to adjust the source light. The phototherapy system may further comprise a treatment patch and a photoactive compound within the treatment region.
