Surface illuminator for photodynamic therapy

Abstract

A device for delivering phototherapeutic light to uniformly illuminate a tissue surface. The device is a bowl-shaped shell with a more-or-less parabolic profile and having an open end and an apex. The inner surface of the shell is adapted to diffusely reflect light with very low absorption by the shell material. A light output end of a fiber optic is introduced into the interior of the shell through a fiber optic port in the shell wall near the apex. The light output end of the fiber is positioned such that light emanating therefrom impinges upon the inner surface of the shell. The shape of the shell causes greater than 60 percent of the light emanating from the fiber to intercept the shell's surface and be diffusely reflected. The diffusely reflected light may then undergo further diffuse reflection within the shell prior to reaching the treatment surface adjacent to the open end of the shell to provide more uniform illumination of the treatment surface than the fiber could otherwise provide. A highly reflective coating is applied to the outer surface of the shell to prevent loss of treatment light from the device. In addition, treatment light which is reflected from the tissue surface and normally lost is captured by the interior surface of the shell and re-reflected to reenter the tissue surface. Thus, little or no treatment light is lost due to reflection or scattering from tissue providing improved efficiency. The shell preferably includes a laterally extending flange around a portion of the open end which can be affixed to the tissue surface thereby preventing relative motion between the illuminator and tissue surface during treatment enabling accurate dosimetry.