Loop diffusers for diffusion of optical radiation

• US 5,632,767 A
• Filed: 06/06/1995
• Issued: 05/27/1997
• Est. Priority Date: 09/09/1994
• Status: Expired due to Fees

• Current Assignee: Cardiofocus Incorporated
• Original Assignee: Cardiofocus Incorporated
• Inventors: Sinofsky, Edward L.
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US08/467,414
• Time in Patent Office: 721 Days
• Field of Search: 606/13-17, 606/7, 606/9-11, 607/88, 607/89
• US Class Current: 607/89
• CPC Class Codes: A61B 2018/2261 with scattering, diffusion or dispersion of light
• CPC Class Codes: A61L 2/10 Ultraviolet radiation
• CPC Class Codes: A61L 29/085 Macromolecular materials
• CPC Class Codes: A61N 5/0601 Apparatus for use inside the body
• CPC Class Codes: C08L 27/12 containing fluorine atoms

Abstract

Methods and apparatus are disclosed for diffusing radiation from a optical fiber to provide a larger exposure area for phototherapy and to provide a substantially uniform energy distribution to a major portion of the exposure area. The invention is especially useful in constructing and implementing circumferential and/or sideways-emitting diffusive tip assemblies, or quasi-spherical diffusive tip assemblies for optical fibers to direct laser radiation in a radially outward pattern relative to the fiber'"'"'s axis. In one aspect of the invention, a plurality of optically-transmissive fiber tip assemblies are employed to act as diffusers. The two or more fiber tip assemblies are deployed as loops which create a uniform illumination pattern. By "looping" or "folding" the fibers, a plurality of fibers can be deployed in conjunction with one another to create geometric exposure patterns with increased energy density while still avoiding "hot spots."

Claims

1. A fiber optic transmission and diffusion apparatus comprising:

a plurality of optical fibers having proximal and distal ends, the proximal ends adapted for coupling to a source of phototherapeutic radiation;

wherein each optical fiber has connected to its distal end a tip assembly for directing radiation outward, each tip assembly being arranged in a loop configuration to form a loop diffuser; and

a housing surrounding the optical fibers and each of said loop diffusers, wherein each of said loop diffusers are expandable out of and retractable back into said housing.

2. The apparatus of claim 1 wherein each tip assembly further comprises a light scattering medium which directs radiation entering the tip assembly outward.

3. The apparatus of claim 1 wherein the apparatus further comprises a control means for moving of each said loop diffusers from a retracted to an expanded state.

4. The apparatus of claim 1 wherein of each the tip assemblies further comprise a tip enclosure containing a scattering medium therein.

5. The apparatus of claim 4 wherein the scattering medium further comprises a polymeric material which has light scattering particles dispersed therein.

6. The apparatus of claim 5 wherein the scatterer particles are chosen from the group consisting of alumina, silica, and titania compounds and mixtures thereof.

7. The apparatus of claim 5 wherein the tip enclosure further comprises a radiation transmissive fluorocarbon polymer.

8. A fiber optic transmission apparatus comprising:

at least one optical fiber having proximal and distal ends, the proximal end adapted for coupling to a source of phototherapeutic radiation;

wherein each optical fiber has connected to its distal end a tip assembly for directing the radiation outward, the tip assembly being arranged in a loop configuration, and wherein each optical fiber is connected to a different tip assembly;

wherein each tip assembly further comprises a tip enclosure containing a scattering medium further comprises a polymeric material which has light scattering particles dispersed therein;

wherein the tip assembly also further comprises a reflective end cap; and

a housing surrounding the at least one optical fiber and receiving the end cap, and at least a portion of each tip assembly.

9. The apparatus of claim 8 wherein each of the tip assemblies further comprise a tip enclosure containing a scattering medium therein.

10. The apparatus of claim 9 wherein the scattering medium further comprises a polymeric material which has light scattering particles dispersed therein.

11. The apparatus of claim 10 wherein the scatterer particles are chosen from the group consisting of alumina, silica, and titania compounds and mixtures thereof.

12. The apparatus of claim 9 wherein the tip enclosure further comprises a radiation transmissive fluorocarbon polymer.

13. A method of phototherapy comprising the steps of:

placing a light diffusive assembly in proximity to a treatment site, the assembly comprising a plurality of light transmissive loop diffuser elements, each loop element further comprising a light scattering medium, such that radiation propagating through the medium is scattered outward,

providing at least one source of therapeutic radiation to the diffusive assembly via an optical fiber connected to each loop element,

disposing said loop elements initially in a retracted state and then redeploying them in an expanded state; and

activating said radiation source to effect treatment with diffused radiation.

14. The method of claim 13 wherein the method further comprises providing at least two sources of radiation to said diffuser element.