Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1998-05-01
2001-04-24
Kamm, William E. (Department: 3762)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C607S091000
Reexamination Certificate
active
06223071
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to photodynamic therapy using an illuminator that provides a uniform distribution of visible light. In particular, the present invention is directed to an apparatus and method for photodynamic treatment (PDT) or diagnosis (PD) of actinic keratosis of the scalp or facial areas of a patient. The present invention is also directed to an apparatus and method for PDT and PD of other indications (e.g., acne) and other areas of the patient (e.g., arms, legs, etc.).
As they are used here, the term “visible light” refers to radiant energy in the visible range of the electromagnetic radiation spectrum, and the term “light” refers to radiant energy including the ultraviolet (UV), infrared (IR) and visible ranges of the electromagnetic radiation spectrum.
2. Description of Related Art
Photodynamic therapy or photochemotherapy is currently being proposed to treat several types of ailments in or near the skin or other tissues, such as those in a body cavity. For example, PDT is being proposed to treat different types of skin cancer and pre-cancerous conditions. In PDT, a patient is administered a photoactivatable agent or precursor of a photoactivatable agent which accumulates in the tissue being diagnosed or treated. An area of the patient which includes the tissue being diagnosed or treated is then exposed to visible light. The visible light causes chemical and/or biological changes in the photoactivatable agent which in turn selectively locate, destroy or alter the target tissue while at the same time causing only mild and reversible damage to other tissues in the treatment area.
General background information on PDT using 5-aminolevulinic acid (“ALA”) as the precursor of a photoactivatable agent can be found in U.S. Pat. No. 5,079,262, entitled “Method of Detection and Treatment of Malignant and Non-Malignant Lesions Utilizing 5-Aminolevulinic Acid,” issued to James C. Kennedy et al. on Jan. 7, 1992, and U.S. Pat. No. 5,211,938, entitled “Method of Detection of Malignant and Non-Malignant Lesions by Photochemotherapy of Protoporphyrin IX Precursors,” issued to James C. Kennedy et al. on May 18, 1993. The contents of these patents are incorporated herein by reference. The publication of James C. Kennedy et al. in the Journal of Clinical Laser Medicine and Surgery on Nov. 5, 1996, entitled “Photodynamic Therapy (PDT) and Photodiagnosis (PD) Using Endogenous Photosensitization Induced by 5-Aminolevulinic Acid (ALA): Mechanisms and Clinical Results,” is also incorporated herein by reference. The “First Phase III” 1996 Annual Report by DUSA Pharmaceuticals, Inc. (Tarrytown, N.Y.) contains pictures and examples of use of the invention, and is also incorporated herein by reference.
As they are used here, the terms ALA or 5-aminolevulinic acid refer to ALA itself, precursors thereof and pharmaceutically acceptable salts of the same.
Most conventional, non-laser light sources are comprised of just three basic functional blocks: an emission source to generate photons (e.g., a light bulb); coupling elements to direct, filter or otherwise conduct the emitted light so that it arrives at the intended target in a usable form; and a control system to start and stop the production of light when necessary. The common office fluorescent lighting fixture is a good example of such a system. In these fixtures, white visible light is produced by a controlled mercury arc discharge which excites inorganic phosphor materials inside a glass tube. Energy transfer from the arc causes visible white light emission from the tube. The emitted visible light is directed toward the work space by reflectors in the lamp housing; the distribution of visible light to the target is often further increased by using a diffusing system. In the typical office setting, visible light production is controlled by a simple snap switch which interrupts the flow of power to the lamp.
For therapeutic reasons it is desirable to have a power output which is uniform in intensity and color. In particular, it is highly desirable to have an illuminator with a spectral output that overlaps to a large extent with the optical activation spectrum of the target photosensitizer. According to one preferred embodiment of the present invention, blue light having wavelengths exceeding 400 nm (nanometers) is particularly advantageous for certain diagnostic purposes and treatments, especially when ALA is the photoactivatable agent used for PD and PDT of actinic keratosis. However, visible light in other ranges of the spectrum, particularly in the green and red ranges between 400 and 700 nm, may also be used.
Conventional illuminators do not produce visible light that is sufficiently uniform in intensity over a contoured surface.
SUMMARY OF THE INVENTION
It is an object of the present invention, therefore, to provide an improved illuminator for PDT and/or PD.
Another object of the invention i s to provide an illuminator for PDT that produces visible light of consistent uniformity in terms of both spectral characteristics and intensity over a diversely contoured surface. As it is used here, the term contoured surface refers to a non-planar surface.
Yet another object of the invention is to provide an illuminator for PDT or PD which produces visible light almost entirely in a selected wavelength range.
A further object of the present invention is to provide an illuminator for irradiating the face or scalp of a patient.
Yet a further object of the present invention is to provide a cooling system for improving the irradiance uniformity of an illuminator.
An additional object of the present invention is to provide an illuminator comprising a finite emitter that approximates the uniform output of an infinite plane emitter by varying the spacing of individual light sources within the illuminator.
Yet an additional object of the present invention is to provide a monitoring system for an illuminator comprising a single visible light sensor monitoring the visible light output of a plurality of light sources and outputting a signal to adjust the visible light output from the plurality light sources.
In accomplishing the foregoing objects, there has been provided according to the present invention an illuminator for PDT or PD of a contoured surface. The illuminator comprises 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 the plurality of light sources with respect to the contoured surface.
In accomplishing the foregoing objects, there is also provided according to the present invention a method of PDT or PD of a contoured surface. The method comprises topically applying 5-aminolevulinic acid to the contoured surface, and irradiating the contoured surface with substantially uniform intensity visible light from a plurality of light sources generally conforming to the contoured surface.
In accomplishing the foregoing objects, there is also provided according to the present invention a cooling system for an illuminator including an elongated light source having a generally arcuate segment connected to a generally straight segment. The cooling system comprises a plenum enclosing the light source; an intake vent to the plenum receiving ambient air, the intake vent being positioned proximate a free end of the generally straight segment; and an exhaust vent from the plenum discharging heated ambient air, the exhaust vent being positioned proximate a connection between the generally arcuate and straight segments. The generally straight segment and a connection between the generally arcuate and straight segments receives greater cooling relative to the generally arcuate segment.
In accomplishing the foregoing objects, there is also provided according to the present invention a method of providing substantially uniform intensity light from an elongated light source having a generally arcuate segment connected to a generally straight segment. The method
Carroll Ronald
Kozodoy Rebecca
Leppelmeier Elton
Lundahl Scott
DUSA Pharmaceuticals Inc.
Foley & Lardner
Kamm William E.
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