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Diffuse reflectance spectroscopy for optical soft tissue differentiation as remote feedback control for tissue‐specific laser surgery
Author(s) -
Stelzle Florian,
TangermannGerk Katja,
Adler Werner,
Zam Azhar,
Schmidt Michael,
Douplik Alexandre,
Nkenke Emeka
Publication year - 2010
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.20909
Subject(s) - diffuse reflectance infrared fourier transform , soft tissue , nervous tissue , diffuse reflection , integrating sphere , linear discriminant analysis , muscle tissue , biomedical engineering , subcutaneous tissue , pathology , materials science , laser , chemistry , anatomy , medicine , optics , computer science , artificial intelligence , physics , biochemistry , photocatalysis , psychiatry , catalysis
Background and Objective Laser surgery does not provide haptic feedback for operating layer‐by‐layer and thereby preserving vulnerable anatomical structures like nerve tissue or blood vessels. Diffuse reflectance spectra can facilitate remote optical tissue differentiation. It is the aim of the study to use this technique on soft tissue samples, to set a technological basis for a remote optical feedback system for tissue‐specific laser surgery. Materials and Methods Diffuse reflectance spectra (wavelength range: 350–650 nm) of ex vivo types of soft tissue (a total of 10,800 spectra) of the midfacial region of domestic pigs were remotely measured under reduced environmental light conditions and analyzed in order to differentiate between skin, mucosa, muscle, subcutaneous fat, and nerve tissue. We performed a principal components (PC) analysis (PCA) to reduce the number of variables. Linear discriminant analysis (LDA) was utilized for classification. For the tissue differentiation, we calculated the specificity and sensitivity by receiver operating characteristic (ROC) analysis and the area under curve (AUC). Results Six PCs were found to be adequate for tissue differentiation with diffuse reflectance spectra using LDA. All of the types of soft tissue could be differentiated with high specificity and sensitivity. Only the tissue pairs nervous tissue/fatty tissue and nervous tissue/mucosa showed a decline of differentiation due to bio‐structural similarity. However, both of these tissue pairs could still be differentiated with a specificity and sensitivity of more than 90%. Conclusions Analyzing diffuse reflectance spectroscopy with PCA and LDA allows for remote differentiation of biological tissue. Considering the limitations of the ex vivo conditions, the obtained results are promising and set a basis for the further development of a feedback system for tissue‐specific laser surgery. Lasers Surg. Med. 42:319–325, 2010. © 2010 Wiley‐Liss, Inc.