Method and apparatus for identifying spectral artifacts

Abstract

The invention provides an apparatus and methods for determining whether spectral data obtained from a region of a tissue sample are affected by an artifact. Artifacts include, for example, lighting artifacts such as glare and shadow and obstruction artifacts, such as blood, a speculum, a smoke tube, or other obstruction. Additionally, the invention provides an apparatus and methods for obtaining redundant spectral data of a given region of a sample. A redundant set of spectral data is useful where one or more artifacts affect some but not all sets of the spectral data, such that the redundant set of data is unaffected by the artifact and is representative of the tissue. An embodiment of the invention comprises using representative spectral data in diagnosing a condition of a region of tissue.

What is claimed is:  
     
         1 - 46 . (canceled)  
     
     
         47 . an apparatus for determining a condition of a region of a tissue sample, the apparatus comprising: 
 illuminating optics for illuminating a region of a tissue sample with electromagnetic radiation incident at a first angle and for illuminating the region of the tissue sample with electromagnetic radiation incident at a second angle;    collecting optics for collecting electromagnetic radiation from the region of the tissue sample; and    a processor adapted to determine a condition of the region of the tissue sample using representative data selected from at least one of: 
 a first set of spectral data corresponding to the collected radiation from the region during illumination with radiation incident at the first angle; and  
 a second set of spectral data corresponding to the collected radiation from the region during illumination with radiation incident at the second angle.  
   
     
     
         48 . The apparatus of  claim 47 , wherein the processor is further adapted to select the representative data based at least in part on a subset of the first set of spectral data and a subset of the second set of spectral data.  
     
     
         49 . The apparatus of  claim 47 , wherein the first set of spectral data comprises reflectance spectral data and the second set of spectral data comprises reflectance spectral data.  
     
     
         50 . The apparatus of  claim 47 , wherein at least one of the first set of spectral data and the second set of spectral data comprises fluorescence spectral data.  
     
     
         51 . The apparatus of  claim 47 , wherein the condition is a state of health.  
     
     
         52 . The apparatus of  claim 51 , wherein the state of health comprises at least one of the conditions of normal squamous tissue, metaplasia, CIN I, CIN II, CIN III, CIS, and cancer.  
     
     
         53 . The-apparatus of  claim 47 , wherein the tissue sample comprises at least one of the group consisting of colorectal, gastroesophageal, urinary bladder, lung, and skin tissue.  
     
     
         54 . The apparatus of  claim 47 , wherein the tissue sample comprises cervical tissue.  
     
     
         55 . The apparatus of  claim 47 , wherein the tissue sample comprises epithelial cells.  
     
     
         56 . An apparatus for determining whether spectral data obtained from a region of a tissue sample are affected by an artifact, the apparatus comprising: 
 illuminating optics for illuminating a region of a tissue sample with electromagnetic radiation incident at a first angle and for illuminating the region of the tissue sample with electromagnetic radiation incident at a second angle;    collecting optics for collecting electromagnetic radiation from the region of the tissue sample; and    a processor adapted to: 
 obtain a first set of spectral data corresponding to collected radiation from the region during illumination of the region with radiation incident at the first angle;  
 obtain a second set of spectral data corresponding to collected radiation from the region during illumination of the region with radiation incident at the second angle; and  
 determine whether the first set of spectral data is affected by an artifact based at least in part on a subset of the first set of spectral data and a subset of the second set of spectral data.  
   
     
     
         57 . The apparatus of  claim 56 , wherein the artifact comprises a lighting artifact.  
     
     
         58 . The apparatus of  claim 57 , wherein the lighting artifact comprises glare.  
     
     
         59 . The apparatus of  claim 57 , wherein the lighting artifact comprises shadow.  
     
     
         60 . The apparatus of  claim 56 , wherein the artifact comprises an obstruction.  
     
     
         61 . The apparatus of  claim 60 , wherein the obstruction comprises blood.  
     
     
         62 . The apparatus of  claim 60 , wherein the obstruction comprises a portion of at least one member of the group consisting of a speculum and a smoke tube.  
     
     
         63 . The apparatus of  claim 60 , wherein the obstruction comprises mucus.  
     
     
         64 . The apparatus of  claim 56 , wherein the first set of spectral data comprises reflectance spectral data and the second set of spectral data comprises reflectance spectral data.  
     
     
         65 . The apparatus of  claim 56 , wherein the processor is further adapted to obtain a third set of spectral data, and wherein the third set of spectral data comprises fluorescence spectral data.  
     
     
         66 . The apparatus of  claim 56 , wherein the processor is adapted to determine whether the first set of spectral data is affected by an artifact by computing a difference between R 1 , a member of the first set of spectral data, and R 2 , a member of the second set of spectral data, and comparing the difference to a constant, where R 1  and R 2  correspond to at least approximately identical wavelengths.  
     
     
         67 . The apparatus of  claim 66 , wherein the difference is a percent difference.  
     
     
         68 . An apparatus for determining whether spectral data corresponding to a region of a tissue sample is affected by an artifact, the apparatus comprising: 
 illuminating optics for illuminating a region of a tissue sample with electromagnetic radiation incident at a first angle and for illuminating the region of the tissue sample with electromagnetic radiation incident at a second angle;    collecting optics for collecting electrogmagnetic radiation from the region of the tissue sample; and    a processor adapted to: 
 obtain a first set of reflectance spectral data corresponding to collected radiation from the region during illumination of the region with radiation incident at the first angle;  
 obtain a second set of reflectance spectral data corresponding to collected radiation from the region during illumination of the region with radiation incident at the second angle;  
 obtain a set of fluorescence spectral data corresponding to the region; and  
 determine whether any of the first set of reflectance spectral data, the second set of reflectance spectral data, and the set of fluorescence spectral data are affected by an artifact based at least in part on at least one of the following: 
 a subset of the first set of reflectance spectral data;  
 a subset of the second set of reflectance spectral data; and  
 a subset of the set of fluorescence spectral data.  
 
   
     
     
         69 . An apparatus for determining a characteristic of a region of a tissue sample, the apparatus comprising: 
 illuminating optics for illuminating a region of a tissue sample with electromagnetic radiation at a first angle and for illuminating the region of the tissue with electromagnetic radiation incident at a second angle;    collecting optics for collecting electromagnetic radiation from the region of the tissue sample; and    a processor adapted to: 
 obtain a first set of reflectance spectral data corresponding to collected radiation from the region during illumination of the region with radiation incident at the first angle;  
 obtain a second set of reflectance spectral data corresponding to collected radiation from the region during illumination of the region with radiation incident at the second angle;  
 determine whether at least one of the first set of reflectance data and the second set of reflectance data is affected by an artifact based at least in part on a subset of the first set of reflectance data and a subset of the second set of reflectance data;  
 reject at least one member of at least one of the first set of reflectance data and the second set of reflectance data determined to be affected by the artifact; and  
 determine a characteristic of the region of the tissue sample based at least in part on at least one member of at least one of the first set of reflectance data and the second set of reflectance data not rejected.  
   
     
     
         70 . The apparatus of  claim 69 , wherein the processor is further adapted to obtain a set of fluorescence spectral data corresponding to collected radiation from the region, and to determine the condition of the region of the tissue sample based at least in part on at least one member of at least ohe of the first set of reflectance data and the second set of reflectance data and at least one member of the set of fluorescence spectral data.