Rapid multi-spectral imaging methods and apparatus and applications for cancer detection and localization

Abstract

Methods and apparatus for video rate or near video rate quantitative imaging of tissue physiological and morphological properties from visible/NIR light spectral images obtain rapid multi-spectral reflectance images by illuminating with a series of spectra containing multiple narrow wavelength bands. An iterative light-transport based inversion algorithm may be applied for correcting the intensity of the spectral images from the geometry/coupling effect as well as from the scattering amplitude distortions. The method can produce video rate absorption as well as scattering spectral images that can be further analyzed very rapidly, using matrix-based rapid inversion algorithms to produce more detailed quantitative images containing information relevant to tissue physiology and morphology.

1 . Apparatus for multispectral imaging of an object, the apparatus comprising:
 a light source for illuminating an object, the light source being adapted to generate simultaneously light in a plurality of narrow wavelength bands to produce a plurality of spectral images, each of the narrow wavelength bands containing different wavelengths within a visible/NIR range, wherein the light source is configured to change the wavelengths of the plurality of narrow bands with time to create different illumination spectral profiles;   an image detecting device for receiving the images; and   an image processing device for processing and analyzing the plurality of spectral images and producing corrected albedo spectral images, or corrected absorption and corrected scattering spectral images, and deriving at least one physiological image of the object and at least one morphological image of the object based from the corrected albedo spectral images or the corrected absorption and corrected scattering spectral images.   
     
     
         2 . An apparatus according to  claim 1  wherein the light source is selected from the group comprising a wide band light source, a programmable digital micro-mirror light source, a laser driven light source and a light emitting diode. 
     
     
         3 . Apparatus according to  claim 2 , wherein the light source comprises a wide band light source which further comprises a rotating filter wheel with a plurality of filters that each pass two or more narrow bands simultaneously, each of the narrow bands being within different wavelength. 
     
     
         4 . Apparatus according to  claim 2  comprising an endoscope, wherein the light source comprises a plurality of light emitting diodes located at a distal end of the endoscope and the plurality of light emitting diodes are arranged to provide uniform illumination of an area of the object in a plurality of narrow wavelength bands. 
     
     
         5 . Apparatus according to  claim 1 , wherein the different narrow band wavelengths are evenly spaced. 
     
     
         6 . Apparatus according to  claim 1 , wherein the different narrow band wavelengths are unevenly spaced. 
     
     
         7 . Apparatus according to  claim 1 , wherein the plurality of narrow bands include at least one narrow band in a blue wavelength range, at least one narrow band in a green wavelength range and at least one narrow band in a red/near infrared wavelength range. 
     
     
         8 . Apparatus according to  claim 1 , wherein the image detecting device comprises at least three CCDs. 
     
     
         9 . Apparatus according to  claim 1  comprising an endoscope wherein the image detecting device is located at a distal end of an endoscope. 
     
     
         10 . Apparatus according to  claim 1 , wherein the image detecting device comprises a Bayer filter mosaic color camera, wherein the Bayer filter mosaic camera is calibrated to obtain reflectance imaging signals that correspond to reflectance images for each of the plurality of narrow wavelength bands. 
     
     
         11 . Apparatus according to  claim 10 , comprising a data store containing calibration information comprising a square calibration matrix. 
     
     
         12 . Apparatus according to  claim 1  comprising an intensity calibration module for obtaining the corrected albedo spectral images or the corrected absorption and corrected scattering spectral images, and a rapid inversion module for quantifying the at least one physiological image and at least one morphological image based on the corrected albedo spectral images or the corrected absorption and corrected scattering spectral images. 
     
     
         13 . Apparatus according to  claim 12  wherein the intensity calibration module uses measured reflectance spectra from a pixel of an image and in-vitro optical absorption spectra of the object to correct the intensity of the plurality of spectral images. 
     
     
         14 . Apparatus according to  claim 12 , wherein the intensity calibration module defines at least a measurement geometry intensity calibration constant Ka to correct for a coupling angle and measurement distance variation between the object and an imaging means, and an albedo correction intensity calibration constant Ks to correct for a relative intensity nature of measurements. 
     
     
         15 . Apparatus according to  claim 14  wherein the apparatus is configured to apply the geometry constant Ka to determine the corrected albedo spectral images and the apparatus is configured to apply the albedo correction constant Ks to determine the corrected absorption and corrected scattering spectral images from an albedo image using an in-vitro absorption spectra of the object. 
     
     
         16 . Apparatus according to  claim 13 , wherein the rapid inversion module is based on a linear matrix inversion model. 
     
     
         17 . A method for quantification of tissue physiological and morphological information, the method comprising the steps of:
 illuminating an object simultaneously with plurality of narrow wavelength bands of illumination, each of the narrow bands having a different wavelength in a visible/NIR range;   producing a plurality of spectral images;   correcting an intensity of the spectral images using measured reflectance spectra from a pixel of the image and obtaining corrected albedo spectral images or corrected absorption and corrected scattering spectral images; and   deriving at least one physiological image and at least one morphological image from the corrected albedo spectral images or the corrected absorption and corrected scattering spectral images.