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Laser-induced autofluorescence spectra studies for in-vivo biologic tissue
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Type
Thesis
Author
Fu, Sheng
Supervisor
Chai, Teck Chee
Abstract
Diagnostic technique based on optical spectroscopy has the potential to link the morphological properties of tissues to individual patient care. In particular, the technique is fast, noninvasive and sensitive in cancer diagnosis. Furthermore, it can be used to elucidate key tissue features, such as cellular metabolic rate, vascularity, intravascular oxygenation and alterations in tissue morphology. These tissue features can be interpreted to shed light on a variety of clinical problems, such as precancerous and cancerous growth and atherosclerosis. If applied successfully, optical spectroscopy has the potential to represent an important step forward advances in diagnostic and therapeutic medical applications.
Spectroscopy technology is a study of the interaction of electromagnetic radiation with matter. There are three aspects to a spectroscopic measurement: irradiation of a sample with electromagnetic radiation; measurement of the absorption, spontaneous emission (fluorescence, phosphorescence) and/or scattering from the sample; and analysis and interpretation of these measurements. Detailed study of absorption, spontaneous emission, for example, autofluorescence provides information that can be classified broadly as analytical, structured, dynamic and energetic.
In the past decade, laser induced autofluorescence (LIAF) spectra technique has been studied and shown to be useful in the early diagnosis of many kinds of organ cancer. LIAF diagnosis technique is so popular because of its several advantages. The technique gives additional diagnostic help to improve the probability of earlier cancer discovery. The technique eliminates the need for surgical removal of biopsy tissue samples, as well as to reduce health care costs as a consequence of eliminating the need for histological examination. Moreover, the immediacy of diagnostic information also reduces the emotional trauma to the patient awaiting the outcome of his medical condition. Hence, the development of efficient and reliable LIAF spectra technique for the early cancer diagnosis is promised. This thesis mainly studies the application of the celebrated LIAF spectra technique to the in vivo diagnosis of skin cancer and diagnosis of early colorectal cancer.
Specifically, in this thesis, LIAF technique is studied to explore the diagnosis information from fluorescence spectra properties of normal and tumor rabbit skin, normal human skin, more important in diagnosis of colorectal tract of rat during their carcinoma formation and human colorectal cancer. A particular emphasis is placed on LIAF early diagnosis of in vivo human colorectal disease like polyps, precancer and cancer. In vitro human colorectal tissues samples are also used in the study. In vivo rabbits' skin cancer model and rats' colorectal tract carcinoma model are built during this study.
In this thesis, comparisons of LIAF spectra from in vivo and in vitro normal rabbit skin tissues are addressed. The results show that the autofluorescence (AF) spectra of in vivo and in vitro skin tissues are similar. This presents an initial step for the future clinical application of LIAF spectra technique to the diagnosis of skin cancer and exhibits an obvious advantage of the in vivo LIAF diagnosis technique than conventional in vitro diagnosis of skin cancer. Comparisons of LIAF spectra from in vivo normal rabbit skin tissues with those from in vivo cancer rabbit skin tissues are presented. The study demonstrates that the LIAF spectra from normal and cancer tissues are different. The study result provides a possibility of LIAF spectra technique application to the in vivo diagnosis of human skin cancer. LIAF spectral intensity ratios from in vivo normal human skin of different genders, ages and races are studied. The study reveals the useful information about the changes of the skin spectra. The results show that the LIAF spectra technique is a promising technique for the investigation of in vivo human skin. Moreover, studies of LIAF spectra changes in colorectal mucosa of in vivo rats during early colorectal carcinoma progression in rats' colorectal tract are presented. The derived diagnosis algorithm displays that LIAF spectra of normal and carcinoma colorectal tissues exhibit the significant differences. The results are potentially useful for the development of clinical study for the diagnosis of human colorectal cancer. The study of LIAF spectra technique to diagnose the in vitro human colorectal normal and cancer tissues is addressed. The result shows that there exists distinct difference between normal and cancer tissues. Finally, co-operated with the doctors of Singapore General Hospital (SGH), the clinical application of LIAF spectra technique to early diagnosis of in vivo human colorectal tract disease like carcinoma is explored. It is the first time for LIAF spectra technique is applied to the clinical diagnosis as an assistant tool of clinical endoscopy in Singapore. The results show that the LIAF spectra technique provides much more advantage for diagnosing the disease of human colorectal tract than conventional colonoscopy and LIAF technique is a real time and noninvasive tool for clinical patient examination.
Spectroscopy technology is a study of the interaction of electromagnetic radiation with matter. There are three aspects to a spectroscopic measurement: irradiation of a sample with electromagnetic radiation; measurement of the absorption, spontaneous emission (fluorescence, phosphorescence) and/or scattering from the sample; and analysis and interpretation of these measurements. Detailed study of absorption, spontaneous emission, for example, autofluorescence provides information that can be classified broadly as analytical, structured, dynamic and energetic.
In the past decade, laser induced autofluorescence (LIAF) spectra technique has been studied and shown to be useful in the early diagnosis of many kinds of organ cancer. LIAF diagnosis technique is so popular because of its several advantages. The technique gives additional diagnostic help to improve the probability of earlier cancer discovery. The technique eliminates the need for surgical removal of biopsy tissue samples, as well as to reduce health care costs as a consequence of eliminating the need for histological examination. Moreover, the immediacy of diagnostic information also reduces the emotional trauma to the patient awaiting the outcome of his medical condition. Hence, the development of efficient and reliable LIAF spectra technique for the early cancer diagnosis is promised. This thesis mainly studies the application of the celebrated LIAF spectra technique to the in vivo diagnosis of skin cancer and diagnosis of early colorectal cancer.
Specifically, in this thesis, LIAF technique is studied to explore the diagnosis information from fluorescence spectra properties of normal and tumor rabbit skin, normal human skin, more important in diagnosis of colorectal tract of rat during their carcinoma formation and human colorectal cancer. A particular emphasis is placed on LIAF early diagnosis of in vivo human colorectal disease like polyps, precancer and cancer. In vitro human colorectal tissues samples are also used in the study. In vivo rabbits' skin cancer model and rats' colorectal tract carcinoma model are built during this study.
In this thesis, comparisons of LIAF spectra from in vivo and in vitro normal rabbit skin tissues are addressed. The results show that the autofluorescence (AF) spectra of in vivo and in vitro skin tissues are similar. This presents an initial step for the future clinical application of LIAF spectra technique to the diagnosis of skin cancer and exhibits an obvious advantage of the in vivo LIAF diagnosis technique than conventional in vitro diagnosis of skin cancer. Comparisons of LIAF spectra from in vivo normal rabbit skin tissues with those from in vivo cancer rabbit skin tissues are presented. The study demonstrates that the LIAF spectra from normal and cancer tissues are different. The study result provides a possibility of LIAF spectra technique application to the in vivo diagnosis of human skin cancer. LIAF spectral intensity ratios from in vivo normal human skin of different genders, ages and races are studied. The study reveals the useful information about the changes of the skin spectra. The results show that the LIAF spectra technique is a promising technique for the investigation of in vivo human skin. Moreover, studies of LIAF spectra changes in colorectal mucosa of in vivo rats during early colorectal carcinoma progression in rats' colorectal tract are presented. The derived diagnosis algorithm displays that LIAF spectra of normal and carcinoma colorectal tissues exhibit the significant differences. The results are potentially useful for the development of clinical study for the diagnosis of human colorectal cancer. The study of LIAF spectra technique to diagnose the in vitro human colorectal normal and cancer tissues is addressed. The result shows that there exists distinct difference between normal and cancer tissues. Finally, co-operated with the doctors of Singapore General Hospital (SGH), the clinical application of LIAF spectra technique to early diagnosis of in vivo human colorectal tract disease like carcinoma is explored. It is the first time for LIAF spectra technique is applied to the clinical diagnosis as an assistant tool of clinical endoscopy in Singapore. The results show that the LIAF spectra technique provides much more advantage for diagnosing the disease of human colorectal tract than conventional colonoscopy and LIAF technique is a real time and noninvasive tool for clinical patient examination.
Date Issued
2003
Call Number
RC268.4 Fu
Date Submitted
2003