Imaging system for detecting diseased tissue using native fluorsecence in the gastrointestinal and respiratory tract

Apparatus for imaging diseases in tissue using autofluorescence comprising:

• a light source for generating excitation light that will cause tissue to generate characteristic autofluorescence light;
• means for illuminating tissue with the excitation light thereby exciting tissue to emit said characteristic autofluorescence light;
• collecting means for gathering reflected excitation light and said characteristic emitted autofluorescence light produced by the tissue;
• a dichroic mirror positioned to receive the reflected excitation light and the emitted autofluorescence light collected by the collecting means, the dichroic mirror operating to separate the spectral components of said autofluorescence light into at least a first spectral band including the reflected excitation light and emitted autofluorescence light having wavelengths where an autofluorescence intensity for abnormal tissue is substantially different from normal tissue and a second spectral band different from said first spectral band including the emitted autofluorescence light having wavelengths where an autofluorescence intensity for abnormal tissue is substantially similar to normal tissue;
• a first optical filter positioned to receive the light within the first spectral band, said first filter operating to remove the reflected excitation light from the light within the first spectral band;
• a second optical filter positioned to receive the light within the second spectral band;
• a first image intensified CCD camera for receiving the autofluorescence light within the first spectral band and for producing a first autofluorescence image signal of the tissue;
• a second image intensified CCD camera for receiving the autofluorescence light within the second spectral band and for producing a second autofluorescence image signal of the tissue;
• a control for adjusting the gain of one of the first or second autofluorescence image signals produced by the intensified CCD cameras as a function of the gain of the other of the first or second autofluorescence image signals;
• and
• a color monitor having at least a first and a second color input, whereby the first color input is coupled to receive the first autofluorescence image signal and the second color input is coupled to receive the second autofluorescence image signal to create a combined, display image in which said abnormal and normal tissue are displayed on the color monitor.

A system for detecting cancerous or precancerous tissue comprising:

• a substantially monochromatic light source for producing excitation light that causes tissue under examination to produce autofluorescence light;
• an endoscope positioned to receive the excitation light and to direct the excitation light into an internal body cavity of a patient and onto the tissue under examination;
• means for collecting the autofluorescence light produced by the tissue under examination;
• a beam splitter for dividing the collected autofluorescence light into a first beam having wavelengths where an intensity of the autofluorescence light from abnormal tissue is substantially different than from normal tissue and a second beam having wavelengths where an intensity of the autofluorescence light from abnormal tissue is substantially the same as from normal tissue;
• a first and second image intensified or non-intensified CCD camera for receiving the first and second beams of autofluorescence light, respectively, the first and second image intensified or non-intensified CCD cameras producing a first and second autofluorescence image signal;
• and
• a color monitor having a red, blue and green color input, the red color input being connected to receive one of the first or second autofluorescence image signals and the blue and green color inputs are connected to receive the other of the first or second autofluorescence image signals in order to produce a display having a color that is representative of a ratio of a magnitude of the first autofluorescence signal and the second autofluorescence signal, said display providing an indication of whether the tissue is normal or abnormal.