Cylindrical light diffusing device for use in photoimmunotherapy

1. A cylindrical light diffusing device comprising a non-circular core fiber having:

i) a non-circular fiber core that provides a “top hat” core irradiance distribution;

ii) light blocking means that prevent frontal light emission from distal end of the non-circular core fiber and return the frontal light back into the non-circular core fiber for redistribution and emission by a light diffusing section; and

iii) the light diffusing section having a diffusing proximal end, a diffusing distal end, and internal scattering features distributed within the non-circular fiber core of the light diffusing section along central axis of the fiber core, wherein interactions among the non-circular fiber core, the light blocking means, and the internal scattering features allow the light diffusion section to (a) provide for a constant mixing of light within the light diffusion section resulting in a redistribution of the light that ensures irradiance in center of the fiber core is replenished; and (b) emits irradiance in a radially symmetric longitudinally “top hat” diffusing irradiance distribution.

2. The light diffusing device of claim 1 wherein the internal scattering features are three cylinders oriented around the central, axis of the fiber core of the light diffusing section of the fiber core at 60° increments.

3. The light diffusing device of claim 1 wherein the internal scattering features are a single line of spheres concentric to the central axis of the fiber core of the light diffusing section.

4. The light diffusing device of claim 1 wherein the internal scattering features are a symmetrical array of elliptical features centered on a radius around the central axis of the fiber core at a predetermined pattern and distributed down a predetermined longitudinal length of the fiber core of the light diffusion section in a pattern selected from the group consisted of linear, nonlinear, spiral, and pseudo random.

5. The light diffusing device of claim 4 wherein the predetermined pattern is at 60° increments.

6. A cylindrical light diffusing device comprising a non-circular core fiber having:

i) a fiber core that provides a “top hat” core irradiance distribution;

ii) light blocking means that prevent frontal light emission from distal end of the non-circular core fiber; and

iii) a light diffusing section having a diffusing proximal end, a diffusing distal end, and internal scattering features distributed within the non-circular fiber core of the light diffusing section along central axis of the fiber core, wherein:

a) the light diffusion section emits irradiance in a radially symmetric longitudinally “top hat” diffusing irradiance distribution;

b) the internal scattering features are pairs of parallel cylinders located at different longitudinal locations along the fiber core of the light diffusing section; wherein (i) each cylinder within each pair of the parallel cylinders is located at a predetermined distance from the central axis of the fiber core of the light diffusing section; and (ii) each pair of the parallel cylinders is oriented at different angles around the central axis than an adjacent pair of the parallel cylinders.

7. The light diffusing device of claim 1 wherein the internal scattering features are created by a laser.

8. The light diffusing device of claim 1 wherein the internal scattering features are located longitudinally in a uniform linear manner concentric with the central axis of the fiber core of the light diffusing section.

9. The light diffusing device of claim 1 wherein pattern of the internal scattering features are located longitudinally in a non-uniform linear manner concentric with the central axis of the fiber core of the light diffusing section and number of internal scattering features per unit length increases from the diffusing proximal end to the diffusing distal end.

10. The light diffusing device of claim 1 wherein size of each of the internal scattering features increases from the diffusing proximal end to the diffusing distal end.

11. The light diffusing device of claim 1 wherein size of each of the internal scattering features decreases from the diffusing proximal end to the diffusing distal end.

12. The light diffusing, device of claim 1 wherein the “top hat” diffusing irradiance distribution means that longitudinal variation of radially emitted irradiance from the light diffusing section is less than +/−20% of the average (“I 0 ”) optical irradiance.

13. The light diffusing device of claim 1 wherein the “top hat” diffusing irradiance distribution means that longitudinal variation of radially emitted irradiance from the light diffusing section is less than +/−15% of the average (“I 0 ”) optical irradiance.

14. The light diffusing device of claim 1 wherein the “top hat” diffusing irradiance distribution means that longitudinal variation of radially emitted irradiance from the light diffusing section is less than +/−10% of the average (“I 0 ”) optical irradiance.

15. A cylindrical light diffusing device comprising a non-circular core fiber having:

i) a non-circular fiber core that provides a “top hat” core irradiance distribution;

ii) light blocking means that prevent frontal light emission from distal end of the non-circular core fiber and return the frontal light back into the non-circular core fiber for redistribution and emission by a light diffusing section; and

iii) the light diffusing section having a diffusing proximal end, a diffusing distal end, and internal scattering features distributed within the non-circular fiber core of the light diffusing section along central axis of the fiber core, wherein interactions among the non-circular fiber core, the light blocking means, and the internal scattering features allow the light diffusion section to provide a constant mixing of light within the light diffusion section resulting in a redistribution of the light that ensures irradiance in center of the fiber core is replenished; and (b) a “top hat” diffusing irradiance distribution, thereby limiting variation of radially emitted irradiance longitudinally from the light diffusing section to be within +/−15% of the average (“I 0 ”) optical irradiance.

16. The light diffusing device of claim 1 wherein latitudinal, cross sectional shape of the non-circular fiber core is selected from the group consisting of hexagon, square, rectangle, triangle, octagon, other regular polygons, and non-regular polygons.

17. The light diffusing device of claim 1 wherein the non-circular core fiber further comprises a covering, a cladding, and an enclosed open cavity located between, and created by, the covering and the cladding; wherein the cladding encloses the core fiber.

18. The light diffusing device of claim 17 wherein the cladding has an exterior, latitudinal, cross sectional shape that is different from the cladding's interior, latitudinal, cross sectional shape.

19. The diffusing device of claim 18 wherein the exterior, latitudinal, cross sectional shape of the cladding is circular; and the interior, latitudinal, cross sectional shape of the cladding is same as the latitudinal, cross sectional shape of the fiber core.

20. The diffusing device of claim 1 wherein the light blocking means is a mirror.

21. A cylindrical light diffusing device comprising a non-circular core fiber having:

i) a non-circular fiber core that provides a “top hat” core irradiance distribution;

ii) light blocking means that prevent frontal light emission from distal end of the non-circular core fiber and return the frontal light back into the non-circular core fiber for redistribution and emission by a light diffusing section;

iii) the light diffusing section having a diffusing proximal end, a diffusing distal end, and internal scattering features distributed within the non-circular fiber core of the light diffusing section are located longitudinally in a non-uniform spiral manner concentric with central axis of the non-circular fiber core of the light diffusing section, wherein interactions among the non-circular fiber core, the light blocking means, and internal scattering features allow the light diffusion section to (a) provide for a constant mixing of light within the light diffusion section resulting in a redistribution of the light that ensures irradiance in center of the fiber core is replenished; and (b) emit irradiance in a radially symmetric longitudinally “top hat” diffusing irradiance distribution; and

iv) a translucent covering over the light diffusion section.