ABSTRACT
Different from endoscopy field imaging modalities, which measure light intensity distributions of very few wavebands over a centimeters size field of view of the tissue under examination, endoscopic spectroscopy measures light intensity as a function of wavelength or frequency over a tissue area (spot/point) of millimeter size or smaller. For diagnostic purposes, field imaging and point spectroscopy are complimentary. Imaging facilitates quick survey and localization of suspicious areas/spots over a large field. Spectroscopy can be used to perform detailed analysis of suspicious area/spots identified by imaging. Imaging determines diagnostic sensitivity, while spectroscopy can improve diagnostic specificity, reducing false positive biopsies. Sometimes, spectroscopy measurements over many randomly selected spots can also improve diagnostic sensitivity, such as in the case of Barrett’s esophagus management. Combination of imaging and spectroscopy often leads to improvement of the overall diagnostic performance. Not all optical spectroscopy modalities can be conveniently implemented for endoscopic applications due to the technical
6.1 Basics of Reflectance and Fluorescence Spectroscopy through Endoscopy .......................................................................................................66
6.2 Spectral Measurement Geometries for Optimizing Imaging System Design ................................................................................................ 67
6.3 Integrated Endoscopy System for Simultaneous Imaging and Spectroscopy without Using a Fiber Catheter ................................................69
6.4 Transport Theory Modeling for Spectral Data Interpretation for Improving Diagnostic Specificity ................................................................... 73 6.4.1 Clinical Measurements ....................................................................... 74 6.4.2 Modeling of the Reflectance Spectra .................................................. 75 6.4.3 Inverse Algorithms ............................................................................. 78 6.4.4 Statistical Analysis ............................................................................. 79 6.4.5 Results ................................................................................................. 79
References ................................................................................................................ 82
challenges associated with endoscopy. We will focus on the three most common spectroscopy modalities: reflectance spectroscopy (including light scattering spectroscopy) and fluorescence spectroscopy in this chapter, and Raman spectroscopy in the next chapter.
