A coating can be applied to an endolumenal wall of a medical device by positioning an optical fiber within the lumen, providing a photo-activated chemical to contact the endolumenal wall, supplying the optical fiber with radiation capable of activating the chemical within the lumen, and withdrawing the optical fiber from the lumen at a controlled rate while the radiation is being emitted from the optical fiber to activate the chemical in close proximity to the endolumenal wall.