A system for disinfecting a medical device is provided. The system includes a light source that generates light having at least one wavelength between about 100 nm and about 500 nm. The system further includes at least one cylindrical optical diffuser disposed in optical communication with at least one interior channel of a medical device, the at least one cylindrical optical diffuser having an outer surface and an end optically coupled to the light source. The at least one cylindrical optical diffuser is configured to scatter guided light through the outer surface to form a light diffuser portion having a length that emits substantially uniform radiation over its length.