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Photodiagnosis of oral malignancy using laser-induced fluorescence and diffuse reflectance spectroscopy

Shodhganga@INFLIBNET

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Title Photodiagnosis of oral malignancy using laser-induced fluorescence and diffuse reflectance spectroscopy
 
Contributor Subhash, N
 
Description Oral cancer represents a significant and growing concern worldwide due to its high prevalence.
Current clinical procedure for detection of oral cancer involves visual inspection
and ensuing biopsy guided histopathological analysis, which is considered as “gold standard”.
This intact procedure is subjective, time consuming, agonizing and costly. Consequently,
exploration and development of new techniques for early oral cancer diagnosis
assume great significance. Researchers have been trying to develop various instruments
based on optical spectroscopic techniques for detection of different types of cancer during
the last two decades. These optical spectroscopic techniques could facilitate noninvasive
and real-time tissue characterization and help to eliminate or reduce the need
for multiple biopsies and increase the cure and survival rates. However, development of
an optimal cost-effective optical system with adequate sensitivity and specificity for clinical
use is still a challenge.
Two non-thermal regimens of light interaction with biological tissues are mainly discussed
in the present work, namely laser-induced autofluorescence (LIAF) and diffuse reflectance
(DR) for detection of oral malignancy or pre-malignancy. The work described in this thesis
is mainly of applied nature, focusing on the analysis of data from ex-vivo tissue samples
and extending these results to diagnose oral cancer in a clinical environment. The present
work mainly aims to improve and contribute to the contemporary research on fluorescence
and diffuse reflectance for tissue characterization. Towards this, a portable and
compact laser-induced fluorescence and reflectance spectroscopic system (LIFRS) has been
developed for point monitoring of fluorescence and diffuse reflectance spectra of oral
tissues/lesions. The LIFRS system uses a 405 nm diode laser in the violet region for excitation
of tissue fluorescence and a white light source (tungsten halogen lamp) for tissue DR
studies.
Both LIAF and DR studies were performed for oral cancer diagnosis, but special emphasis
was given to discern between different tissue types and for early detection of the disease.
The normal LIAF and DR fingerprint spectra form healthy population exhibit different characteristics
with the tissue abnormality. In DR studies, a novel approach that uses oxygenated
hemoglobin absorption band ratio (R545/R575) was introduced for tissue grading
and early detection of cancer. This work also introduces a new criteria based on spectral
ratio reference standard (SRRS) scatter plots of fluorescence intensity ratios (F500/F635,
F500/F685 and F500/F705) for oral pre-cancer detection and tissue grading with excellent
diagnostic accuracies, validated with the blind-tests. In addition, optimum accumu-
Abstract
Bibliography p. 159-175
 
Date 2010-11-26T12:05:00Z
2010-11-26T12:05:00Z
2010-11-26
August, 2008
 
Type Ph.D.
 
Identifier http://hdl.handle.net/10603/1258
 
Language English
 
Rights university
 
Format 175P.
DVD
 
Publisher Cochin
Cochin University of Science and Technology
Centre of Earth Science Studies
 
Source INFLIBNET