Laser apparatus for concurrent analysis and treatment

• US 4,973,848 A
• Filed: 07/28/1989
• Issued: 11/27/1990
• Est. Priority Date: 07/28/1989
• Status: Expired due to Fees

• Current Assignee: George Wolken Jr, James S. Mccaughan Jr
• Original Assignee: J Mccaughan
• Inventors: Kolobanov, Alexander S., Barabash, Rostislav D.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US07/388,983
• Time in Patent Office: 487 Days
• Field of Search: 250/461.2, 250/461.1, 250/458.1, 128/634, 128/633, 128/665
• US Class Current: 250/458.1
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61B 2017/00057 Light
• CPC Class Codes: A61B 2018/00636 Sensing and controlling the application of energy
• CPC Class Codes: A61B 2018/00904 Automatic detection of target tissue
• CPC Class Codes: A61B 2018/20359 by movable mirrors, e.g. galvanometric
• CPC Class Codes: A61N 2005/0642 Irradiating part of the body at a certain distance
• CPC Class Codes: A61N 5/062 Photodynamic therapy, i.e. excitation of an agent

Abstract

The present invention discloses an apparatus in which two laser beams are concurrently scanned across a region of tissue to be treated by laser therapy. A first "analysis" beam is used to excite characteristic light emission or reflection from the surface. This scattered light is detected and analyzed to determine the properties of the small portion of the surface under illumination and at that instant by the analysis beam. A second "treatment" beam is scanned concurrently with the analysis beam. The properties of the surface at each small region (as determined by the analysis beam) are used to adjust the power and other properties of the treatment beam such that each small region of the surface receives optimal exposure. Automatic controlled scanning of both beams allows very rapid treatment of large areas of tissue, while adjusting in real-time the power levels of the lasers to achieve optimal treatment at each point treated.

Claims

1. An apparatus for concurrent laser analysis and laser treatment of a two-dimensional surface comprising:

(a) a first laser, emitting a first beam of laser light having a wavelength and power sufficient to cause characteristic fluorescence when said first beam is directed upon the surface of a target requiring treatment;

(b) a second laser, emitting a second beam of laser light having a wavelength and power sufficient, when directed upon said target surface, to cause desired alterations in the properties of said target;

(c) a first means for modulating the intensity of said first laser beam;

(d) a second means for modulating the intensity of said second laser beam;

(e) a first and a second means for focusing said first laser beam and said second laser beam, respectively, onto the same point of said target surface;

(f) a means for detecting and measuring the intensity of characteristic fluorescence emitted by said target when struck by said first laser beam;

(g) a means for regulating the intensity of said second laser beam in accordance with the measured fluorescence caused by said first laser beam;

(h) first and second two-coordinate optical scanners arranged so as to scan simultaneously said first laser beam and said second laser beam, respectively, over the same points on the surface of said target;

(i) a signal generator providing concurrent scan and trigger pulses for the control of said first and second optical scanners.

2. An apparatus as in claim (1) wherein said intensity regulating means comprises optical filtering means and feedback control circuits automatically controlling the intensity of said second laser beam by means of adjustments to said second modulator.

3. An apparatus as in claim (1) further comprising:

(a) a means for detecting the light from said first laser beam which is diffusely reflected from said target;

(b) a means to display said diffusely reflected light for visualization by an operator, creating thereby an image of said target area under treatment.

4. An apparatus as in claim (1) wherein said first and second lasers comprise semiconductor lasers pumped by electron beams, and wherein said first and second optical scanners comprise electrostatic deflecting means for deflecting said electron beams as an integral part of said lasers.

5. An apparatus as in claim (3) further comprising:

(a) a means for the display and visualization by said operator said characteristic fluorescence emitted by said target;

(b) a means for said operator to control said scanning of both said first and second laser beams over said target in response to information provided said operator by said visualizations means and said measured fluorescence intensity.

6. An apparatus as in claim (1) further comprising a means for joining said first laser beam and said second laser beam into a single beam of partially coherent light having a common direction of travel.

7. An apparatus as in claim (6) further comprising a single two-dimensional optical scanner positioned so as to scan said single joined beam over said target surface.

8. An apparatus as in claim (1) further comprising a narrowband optical filter transmitting at the wavelength of said first laser beam and positioned to filter said fluorescence from said first laser beam in reaching said detector thereof, and wherein said detector of said fluorescence from said first laser beam comprises a rectifying detector adjusted to rectify and detect at said modulation frequency of said first laser beam.