Illumination devices for photodynamic therapy of the oral cavity

Three compact and efficient designs are proposed to deliver an average irradiance of 50 mW/cm(2) with spatial uniformity well above 90% over a 25 mm(2) target area for photodynamic therapy of the oral cavity. The main goal is to produce uniform illumination on the target while limiting irradiation of healthy tissue, thus overcoming the need of shielding the whole oral cavity and greatly simplifying the treatment protocol. The first design proposed consists of a cylindrical diffusing fiber placed in a tailored reflector derived from the edge-ray theorem with dimensions 5.5 × 7.2 × 10 mm(3); the second device combines a fiber illuminator and a lightpipe with dimensions 6.8 × 6.8 × 50 mm(3); the third design, inspired by the tailored reflector, is based on a cylindrical diffusing fiber and a cylinder reflector with dimensions 5 × 10 × 11 mm(3). A prototype for the cylinder reflector was built that provided the required illumination for photodynamic therapy of the oral cavity, producing a spatial uniformity on the target above 94% and an average irradiance of 51 mW/cm(2) for an input power of 70 mW.