In vivo fluorescence photometer

• US 5,062,431 A
• Filed: 03/30/1990
• Issued: 11/05/1991
• Est. Priority Date: 11/08/1988
• Status: Expired due to Term

• Current Assignee: Health Research Incorporated
• Original Assignee: Health Research Incorporated
• Inventors: Potter, William R.
• Primary Examiner(s): Smith, Ruth S.
• Application Number:
  US07/502,447
• Time in Patent Office: 585 Days
• Field of Search: 128/665, 128/664, 128/666, 128/633, 128/634, 128/395, 128/398, 606/3
• US Class Current: 600/478
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/418 lymph vessels, ducts or nodes
• CPC Class Codes: A61N 5/0601 Apparatus for use inside the body
• CPC Class Codes: A61N 5/062 Photodynamic therapy, i.e. excitation of an agent

Abstract

A method and apparatus for in vivo detection of abnormal tissue in patients by irradiating a diagnostic region simultaneously with at least two wavelengths of incident light, and detecting the resulting fluorescence of normal and abnormal tissue. The patient is provided with a photosensitizer which preferentially collects in abnormal tissue, and beams of light--preferably at about 612 and 632.8 nm--are directed to the diagnostic region. The beams of light are chopped at 90 and 135 Hz, respectively. Fluorescent light from the diagnostic region is then detected, and an electronic signal is generated relating to the intensity of the fluorescence. Because of the chopping of the incident beams, the fluorescent light and the resulting electronic signal area also chopped. The electronic signal is provided as input to phase-locked amplifier circuitry, which differentiates between the contribution to the signal resulting from each of the 612 and 632.8 nm incident beams. A difference signal is provided as output to headphones, and the operator of the apparatus is notified of presence of abnormal tissue by changes in pitch of the difference signal. The source for the light may be lasers or an arc lamp, and there may be three or more incident wavelengths used.

Claims

1. An apparatus for in vivo detection of abnormal tissue in a patient, comprising:

at least one light source for providing a first light beam having a first wavelength and a second light beam having a second wavelength;

means for imparting characteristics to said first and second beams for differentiating between them;

means for transmitting said first and second beams simultaneously to a diagnostic region of the patient;

means for detecting a fluorescent signal from both the abnormal tissue in the patient and from normal tissue in the vicinity of the abnormal tissue, said fluorescent signal resulting from irradiation of the diagnostic region by said first and second beams and having an intensity related to an amount of each of the normal and abnormal tissue present at the diagnostic region;

means for converting said fluorescent signal to a first electronic signal having a signal strength related to said intensity;

means for electronically differentiating a first portion of said first electronic signal from a second portion of said first electronic signal, by means of said characteristics, where said first portion results from said first incident beam and said second portion results from said second incident beam;

means for generating a second electronic signal relating to a difference in magnitude between said first and second portions of said first electronic signal; and

means for providing said second electronic signal as an output for indicating the presence of abnormal tissue.

2. The apparatus of claim 1, wherein said imparting means includes a first chopper for interrupting said first beam at a first frequency and a second chopper for interrupting said second beam at a second frequency.

3. The apparatus of claim 2, wherein said differentiating means includes a first amplifier having a first filter for passing said first frequency, and a second amplifier having a second filter for passing said second frequency.