Many current light diffusers for photodynamic therapy are inflexible, and the applied light dose is difficult to adjust during treatment, especially on complex body surfaces. A thin and flexible luminous textile is developed using plastic optical fibers as a light distributor. The textile diffuser is evaluated for flexibility, irradiance, brightness distribution, and temperature rise with a 652-nm laser set to . The bending force of the textile diffuser resembles a defined optical film. On the textile surface, an average output power of is measured, corresponding to a transmission rate of on an area of . Aluminum backing enhances the irradiance to the face (treatment side). The measured brightness distribution seems to lie within a range similar to other photodynamic therapy (PDT) devices. A power setting of increases the temperature of the textile diffuser surface of up to , and raises the temperature above . Results confirm that the flexible textile diffuser supplies suitable radiation for low fluence rate photodynamic therapy on an area of several .