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Diagnosing colorectal tumor using fluorescence techniques
Author
Ang, Wuan Suan
Supervisor
Kwek, Leong Chuan
Abstract
The success of cancer treatment depends in most cases on the degree of invasion and metastasis of the lesion. Present therapeutic methods like radical surgery, chemotherapy, radiotherapy, or photodynamic therapy can offer a realistic chance of survival for many types of cancers as long as the tumor remains local. This implies the necessity of a diagnostic tool that is sensitive to early stage cancers. Laser-Induced Auto fluorescence (LIAF) makes use of the different fluorescent spectra obtained from the cancerous and normal tissues that were excited by high-frequency light source, while time-resolved auto fluorescence monitors events that occur during the lifetime of the excited state of the naturally occurring fluorophores in the specimen. Earlier studies have shown that LIAF is effective in detecting early cancers in vivo as well as in vitro provided that the tissue samples are tested as soon as possible after being removed from the patient to avoid any morphological degradation and contamination. Unfortunately in many cases, tissue samples are not readily available and often they have to be frozen for some time before being tested. Therefore, in this study, we aim to make a comparison between the effectiveness of LIAF and time-resolved auto fluorescence techniques for characterizing normal and tumor tissue samples that are frozen for a period of time. Both LIAF and time-resolved auto fluorescence spectra are obtained from two sets of colorectal tissue samples frozen for different lengths of time. By analyzing spectra from both LIAF and time-resolved techniques, we demonstrated that while LIAF is no longer effective in differentiating cancerous from normal tissues by the conventional peak intensity ratio comparison method, student's t-tests applied to the auto fluorescence lifetimes clearly show that there is still a significant difference between the lifetimes of normal and cancerous colorectal tissues after a period of freezing. This leads us to conclude that for frozen colorectal tissues, time-resolved auto fluorescence is a better technique for differentiating tumor from normal tissues than LIAF, and that a possible potential application of the time-resolved auto fluorescence technique may be in forensic studies.
Date Issued
2006
Call Number
RC78.7.F5 Ang
Date Submitted
2006