Illuminator for photodynamic therapy and diagnosis which produces substantially uniform intensity visible light

• US 6,223,071 B1
• Filed: 05/01/1998
• Issued: 04/24/2001
• Est. Priority Date: 05/01/1998
• Status: Expired due to Term

• Current Assignee: Dusa Pharmaceuticals (Sun Pharmaceutical Industries Limited)
• Original Assignee: Dusa Pharmaceuticals (Sun Pharmaceutical Industries Limited)
• Inventors: Lundahl, Scott, Carroll, Ronald, Kozodoy, Rebecca, Leppelmeier, Elton
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US09/070,772
• Time in Patent Office: 1,089 Days
• Field of Search: 607/88, 607/90, 607/91, 600/476
• US Class Current: 600/476
• CPC Class Codes: A61B 2017/00057 Light
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61N 2005/0642 Irradiating part of the body at a certain distance
• CPC Class Codes: A61N 2005/0655 Tubes
• CPC Class Codes: A61N 5/0616 Skin treatment other than tanning
• CPC Class Codes: A61N 5/0617 Hair treatment
• CPC Class Codes: A61N 5/062 Photodynamic therapy, i.e. excitation of an agent

Abstract

An apparatus and method for photodynamic therapy or photodynamic diagnosis using an illuminator comprising a plurality of light sources generally conforming to a contoured surface and irradiating the contoured surface with substantially uniform intensity visible light. The light sources may comprise generally U-shaped fluorescent tubes that are driven by electronic ballasts. Adjustment of the ballast voltage controls the output power of the tubes. The tubes are supported by a sheet-metal or plastic housing and are covered by a polycarbonate shield which directs cooling airflow within the unit and prevents glass-patient contact in the event of tube breakage. An aluminum reflector located behind the tubes increases both the output irradiance and the uniformity of the output distribution. The spacing of the U-shaped tubes is varied to increase the output at the edges of the illuminator to make the output more uniform. Also, different portions of the tubes are cooled at different amounts, to improve uniformity. A light sensor monitors output from the U-shaped tubes to provide a signal for adjusting the output from the tubes.

Claims

1. An illuminator for photodynamically diagnosing or treating a contoured surface, the illuminator comprising:

a plurality of light sources generally conforming to the contoured surface and irradiating the contoured surface with substantially uniform intensity visible light; and

a housing supporting said plurality of light sources with respect to the contoured surface.

2. The illuminator according to claim 1, wherein each of said plurality of light sources comprises a generally arcuate central region and arms extending from respective ends of said central region;

and

wherein said housing comprises an opening to allow ingress/egress of the contoured surface between said arms toward said central region.

3. The illuminator according to claim 2, wherein said central region is generally semicircular and said arms extend generally parallel to one another from said respective ends of said central region.

4. The illuminator according to claim 2, wherein said arcuate region has an approximately 19 centimeter radius of curvature.

5. The illuminator according to claim 2, further comprising:

a cooling system adapted for providing greater cooling to said arms and said ends of said central region relative to said central region.

6. The illuminator according to claim 5, further comprising:

a reflector being supported by said housing and interposed between said housing and said plurality of light sources; and

a shield being supported by said housing and interposed between said plurality of light sources and the contoured surface;

wherein said cooling system includes;

intake vents in said shield adapted for receiving ambient air;

intermediate vents in said reflector adapted for transferring heated ambient air from a first zone between said reflector and said shield to a second zone between said reflector and said housing; and

exhaust vents in said housing adapted for discharging heated ambient air.

7. The illuminator according to claim 6, further comprising:

at least one fan adapted for drawing the ambient air in through said intake vents and expelling the heated ambient air through said exhaust vents.

8. The illuminator according to claim 6, wherein said intake vents include perforations in said shield proximate free ends of said arms, and said intermediate vents include perforations in said reflector proximate said ends of said central region.

9. The illuminator according to claim 1, wherein said plurality of light sources are generally parallel to one another and lateral spacing between adjacent ones of said plurality of light sources varies along the contoured surface.

10. The illuminator according to claim 9, wherein said lateral spacing is greater between inner ones of said plurality of light sources than between outer ones of said plurality of light sources.

11. The illuminator according to claim 10, wherein said housing includes an emitting area;

and wherein said plurality of light sources include seven fluorescent bulbs having first lateral spacings from an innermost one of said fluorescent bulbs to each adjacent fluorescent bulb, second lateral spacings between intermediate fluorescent bulbs of either side of said innermost one of said fluorescent bulbs, third lateral spacings between outermost ones of said fluorescent bulbs and respective adjacent intermediate fluorescent bulbs, and fourth lateral spacings between outermost ones of said fluorescent bulbs and edges of said emitting area; and

wherein said first lateral spacings are approximately 7 centimeters, said second lateral spacings are approximately 5 centimeters, said third lateral spacings are approximately 3.5 centimeters and said fourth lateral spacings are approximately 2.5 centimeters.

12. The illuminator according to claim 1, wherein said light sources generate visible light substantially entirely within the blue region.

13. The illuminator according to claim 12, wherein said light has a nominal peak wavelength of 417±

5 nanometers and a nominal bandwidth of 30 nanometers.

14. The illuminator according to claim 1, wherein each of said plurality of light sources includes a fluorescent tube internally coated with Sr₂P₂O₇:

Eu.

15. The illuminator according to claim 1, wherein said plurality of light sources provide a maximum total emitting area of approximately 2850 square centimeters and a minimum therapeutically active emitting area of approximately 1350 square centimeters.

16. The illuminator according to claim 1, further comprising:

a shield being supported by said housing and interposed between said plurality of light sources and the contoured surface;

wherein irradiance from said plurality of light sources over an active emitting area at a distance of 2 inches away from said shield and at a distance of 4 inches away from said shield is at least 70% of maximum irradiance.

17. The illuminator according to claim 16, wherein irradiance from said plurality of light sources over an active emitting area is at least 60% of maximum irradiance at all operating distances from said shield.

18. The illuminator according to claim 1, wherein power output from said plurality of light sources is approximately 9 to 11 milliwatts per square centimeter.

19. The illuminator according to claim 18, wherein said power output is approximately 10 milliwatts per square centimeter.

20. The illuminator according to claim 1, further comprising:

a shield being supported by said housing and interposed between said plurality of light sources and the contoured surface, said shield filtering out ultraviolet light emitted from said plurality of light sources toward the contoured surface.

21. The illuminator according to claim 20, wherein said shield is made of polycarbonate.

22. The illuminator according to claim 20, wherein said shield includes a light diffuser.

23. The illuminator according to claim 1, further comprising:

at least one electric circuit for powering said plurality of light sources, said electric circuit including;

an activation/deactivation controller for energizing/de-energizing said plurality of light sources;

an exposure controller for de-energizing said plurality of light sources after a selected dose of said light irradiates the contoured surface; and

a ballast for initiating and maintaining voltage through said plurality of light sources.

24. The illuminator according to claim 23, wherein said exposure controller is a timer for de-energizing said plurality of light sources after a selected period.

25. The illuminator according to claim 24, wherein said timer includes at least one control for setting a time limit for exposing the contoured surface to said light.

26. The illuminator according to claim 23, wherein said at least one electric circuit further includes:

a visible light sensor for detecting said light from at least one of said plurality of light sources, said visible light sensor outputting a first signal corresponding to said light;

a detector for monitoring input voltage to said ballast, said detector outputting a second signal corresponding to said input voltage;

a transformer for supplying a plurality of possible input voltages to said ballast;

a switch array for selecting one of said plurality of possible input voltages to be supplied to said ballast; and

a processor for controlling said at least one electric circuit, said processor receiving said first and second signals and controlling said switch array;

wherein said processor adjusts said input voltage to said ballast for correcting output of said light from said plurality of light sources so as to maintain said substantially uniform intensity visible light irradiating the contoured surface.

27. The illuminator according to claim 26, wherein said transformer is a buck/boost auto-transformer.

28. The illuminator according to claim 26, wherein said at least one electric circuit further includes:

an indicator for indicating the status of the illuminator, said indicator being controlled by said processor.

29. The illuminator according to claim 23, wherein said activation/deactivation controller includes:

a main power switch for controlling entry of power from an external source; and

a key switch for restricting unauthorized use of the illuminator.

30. The illuminator according to claim 1, further comprising:

a visible light sensor being supported by said housing;

a reflector being supported by said housing and interposed between said visible light sensor and said plurality of light sources;

a first aperture in said partition adapted for admitting visible light from a first one of the plurality of light sources to said visible light sensor, said first aperture being spaced from said visible light sensor a first distance and having a first cross-sectional area; and

a second aperture in said partition adapted for admitting visible light from a second one of said plurality of light sources to said visible light sensor, said second aperture being spaced from said visible light sensor a second distance and having a second cross-sectional area;

wherein a ratio of said first and second cross-sectional areas is proportional to inverse squares of said first and second distances; and

wherein said visible light sensor is adapted for monitoring light output from said first and second ones of said plurality of light sources and outputting a signal to adjust visible light output from said plurality of light sources so as to provide said substantially uniform intensity visible light irradiating the contoured surface.

31. The illuminator according to claim 30, further comprising:

a third aperture in said reflector adapted for admitting visible light from a third one of said plurality of light sources to said visible light sensor, said third aperture being spaced from said visible light sensor a third distance and having a third cross-sectional area;

wherein said second and third ones of said plurality of light sources are substantially equally spaced from opposite sides of said first one of said plurality of light sources, said second and third distances are substantially equal, and said second and third cross-sectional areas are substantially equal; and

wherein said visible light sensor is adapted for monitoring light output from said first, second and third ones of said plurality of light sources and outputting a signal to adjust visible light output from said plurality of light sources so as to provide said substantially uniform intensity visible light irradiating the contoured surface.

32. An illuminator for photodynamically diagnosing or treating a contoured surface, the illuminator comprising:

a plurality of light sources, the plurality of light sources being curved to generally conform to the contoured surface and irradiate the contoured surface with substantially uniform intensity visible light; and

a housing supporting said plurality of light sources with respect to the contoured surface.

33. The illuminator according to claim 32, wherein said plurality of light sources are elongated.

34. The illuminator according to claim 32, further comprising:

a cooling system adapted for providing greater cooling to portions of said light sources make intensity more uniform.

35. The illuminator according to claim 32, wherein said plurality of light sources are generally parallel to one another and lateral spacing between adjacent ones of said plurality of light sources varies along the contoured surface.

36. The illuminator according to claim 32, wherein said light sources generate visible light substantially entirely within the blue region.