Vision enhancement system for detection of oral cavity neoplasia based on autofluorescence

Abstract

Background. Early detection of squamous cell carcinoma (SCC) in the oral cavity can improve survival. It is often difficult to distinguish neoplastic and benign lesions with standard white light illumination. We evaluated whether a technique that capitalizes on an alternative source of contrast, tissue autofluorescence, improves visual examination.Methods. Autofluorescence of freshly resected oral tissue was observed visually and photographed at specific excitation/ emission wavelength combinations optimized for response of the human visual system and tissue fluorescence properties. Perceived tumor margins were indicated for each wavelength combination. Punch biopsies were obtained from several sites from each specimen. Sensitivity and specificity were evaluated by correlating histopathologic diagnosis with visual impression.Results. Best results were achieved with illumination at 400 nm and observation at 530 nm. Here, sensitivity and specificity were 91% and 86% in discrimination of normal tissue from neoplasia. This compares favorably with white light examination, in which sensitivity and specificity were 75% and 43%.Conclusions. Oral cavity autofluorescence can be easily viewed by the human eye in real time. Visual examination of autofluorescence enhances perceived contrast between normal and neoplastic oral mucosa in fresh tissue resections.

Analysis of surgical margins in oral cancer using in situ fluorescence spectroscopy

“…However, this approach does not completely remove all the abnormal tissue in all individuals. Poh et al and Svistun et al showed that most tumors have occult changes and that the width for subclinical extension ranges between 4 and 25 mm, often extending in at least one direction by over 10 mm with some potentially malignant disorder, thus increasing the chance of tumor recurrence [21,23]. In this study, all surgical margins were clinically normal and had negative results for malignancy, but subclinical alterations showed mild spectral changes confirming the need for further investigation at the molecular level.…”

“…For instance, direct fluorescence visualization has been used in different tissues and organs and successfully distinguished premalignant and malignant lesions that cannot be detected by naked eye [22][23][24][25][26]. In our study, spectroscopy satisfactorily discriminated normal tissue and slightly altered mucosa from cancerous lesions.…”

Design and preliminary analysis of a study to assess intra-device and inter-device variability of fluorescence spectroscopy instruments for detecting cervical neoplasia

“…The measured fluorescence intensity also indicates absorption, particularly from hemoglobin. There has been some success using fluorescence spectroscopy to detect cancer and pre-cancer [1][2][3][4][5]. One of the important issues in the successful implementation of any spectroscopic device is the proper calibration and the control of extraneous variation.…”

Real‐time detection of epidermal growth factor receptor expression in fresh oral cavity biopsies using a molecular‐specific contrast agent

“…Optical techniques can quantitatively assess the presence of bound contrast agent noninvasively in near real-time, in contrast to current diagnostic techniques of invasive biopsy and delayed microscopic assessment. The optical signature of the contrast agent could be easily detected and quantified in vivo using spectroscopy, [6][7][8][9][10][11][12] low resolution 2D imaging [13][14][15][16] or high resolution 3D confocal microscopy. [17][18][19][20][21][22][23][24][25] Several studies have previously investigated the use of in vivo fluorescence spectroscopy based on autofluorescence to diagnose malignancy in the oral cavity.…”

“…The longer excitation wavelength of the fluorescent dye avoids interference from many of the molecules present in tissue that absorb and scatter light at the optimal wavelengths for autofluorescence (300-440 nm). 7,8,[10][11][12][13] Using a dye that fluoresces at a longer wavelength also allows for increased penetration depth. Also, the intensity of fluorescence emitted by the contrast agent is higher than that of endogenous fluorophores, resulting in a stronger optical signal.…”