Therapeutic light delivery apparatus, method, and system
An optical delivery apparatus is disclosed including: an optical fiber extending between a distal end having a distal end face and a proximal end having a proximal end face, an optical element positioned to receive the light emitted from the distal end face and direct the light to an illumination region; and a non-metallic housing containing the optical fiber and the optical element and maintaining the relative position of the optical fiber and the optical element.
1. An optical delivery apparatus comprising:
an optical fiber extending between a distal end having a distal end face and a proximal end having a proximal end face, said fiber configured to receive light from at least one source at the proximal end face, transmit the light from the proximal end to the distal end, and emit the light from the distal end face; and
an optical element positioned to receive the light emitted from the distal end face and direct the light to an illumination region;
wherein the optical element comprises a diffuser tip assembly adapted to receive the distal end of optical fiber, the assembly comprising:
a reflective cavity comprising:
a first reflector positioned proximal the distal end of the received fiber and comprising an aperture adapted to admit light emitted from the fiber into the cavity; and
a second reflector positioned distal the first reflector; and
a diffuser tube positioned between the first and second reflectors about a cavity axis extending from the first reflector to the second reflector, the diffuser tube comprising an inner void surrounded by an outer portion comprising a diffusive scattering material;
wherein the cavity and diffuser tube are arranged such that at least a portion of light admitted into the cavity is scattered by the diffusive scattering material out of the tip assembly through the outer portion in a direction transverse to the cavity axis.
2. The apparatus of claim 1 , wherein the cavity and diffuser tube are configured such that:
light admitted into the cavity is directed from the aperture towards the second reflector;
a portion of the light directed towards the second reflector impinges upon the diffusive scattering material and is scattered out of the tip assembly in a direction transverse to the axis; and
at least a portion of unscattered light impinges upon the second reflector and is reflected back towards the first reflector; and a portion of the light directed back towards the first reflector impinges upon the diffusive scattering material and is scattered out of the tip assembly in a direction transverse to the axis.
3. The apparatus of claim 2 , wherein the cavity and diffuser tube are configured such that light admitted into the cavity travels multiple passes between the first and second reflectors, and on each pass, at least a portion of the light is scattered by the diffusive scattering material out of the tip assembly m a direction transverse to the axis.
4. The apparatus of claim 3 , wherein the light scattered out of the tip assembly on each pass combine to produce a cumulative illumination pattern.
5. The apparatus of claim 4 , wherein the cumulative illumination pattern is characterized by substantially uniform axial intensity profile along at least a portion of the diffuser tube.
6. The apparatus of claim 5 , wherein the cumulative illumination pattern is characterized by a substantially uniform azimuthal illumination profile.
7. The apparatus of claim 6 , wherein the cumulative illumination pattern is characterized by substantially proscribed illumination in the direction parallel to the axis.
8. The diffuser tip assembly of any of claim 7 , wherein the cumulative illumination pattern is a substantially uniform cylindrical illumination pattern emitted radially from the outer surface of the diffuser tube.
9. The apparatus of claim 8 , wherein the cumulative illumination pattern is determined by at least on at least one chosen from the list consisting of a length of the diffuser tube, the diameter of the inner void of the diffuser tube, a numerical aperture associate with the aperture in the first reflector.
10. The apparatus of claim 1 , wherein the inner void is filled with a substantially transparent non-scattering material.
11. The apparatus of claim 1 , wherein the at least one of the first and second reflectors comprises a curved reflector.
12. The apparatus of claim 1 , wherein the first reflector is a diffuse reflector and the second reflector is a specular reflector.
13. The apparatus of claim 1 , wherein the ratio of the distance between the first reflector and the second reflector along the cavity axis to the outer diameter of the diffusion tube is about 10 or less.
14. The apparatus of claim 1 , wherein the ratio of the distance between the first reflector and the second reflector along the cavity axis to the outer diameter of the diffusion tube is about 1 or less.
15. The apparatus of claim 1 , wherein the ratio of the distance between the first reflector and the second reflector along the cavity axis to the outer diameter of the diffusion tube is about 0.1 or less.
16. The apparatus of claim 1 , wherein the diffusive scattering material comprises at least one selected from the list consisting of a plastic, a glass, a polymer, and a fluid.
17. The apparatus of claim 1 , wherein the diffusive scattering material comprises PTFE.
18. The apparatus of claim 1 , further comprising a substantially transparent outer jacket adapted to contain the reflective cavity and the diffuser tube.
19. The apparatus of claim 1 , wherein the diffusive scattering material is adapted to scatter light in the near infrared.
20. The apparatus of claim 1 , wherein the tip assembly is adapted to scatter about 80% or more of the light delivered from the fiber while absorbing about 20% or less of the light delivered from the fiber.