Clinical imaging fluorescence apparatus for the endoscopic photodetection of early cancers by use of Photofrin II

Abstract

A fluorescence imaging device applied to the detection of early cancer is described. The apparatus is based on the imaging of laser-induced fluorescence of a dye that localizes in a tumor with a higher concentration than in the surrounding normal tissue after iv injection. Tests carried out in the upper aerodigestive tract, the tracheobronchial tree, and the esophagus with Photofrin II (1 mg/kg of body weight) as the fluorescent agent are reported as examples. The fluorescence is induced by violet (410-nm) light from a continuous-wave (cw) krypton-ion laser. The fluorescence contrast between tumor and surrounding tissue is enhanced by real-time image processing. This is done by the simultaneous recording of the fluorescence image in two spectral domains (470-600 and 600-720 nm), after which these two images are digitized and manipulated with a mathematical operator (look-up table) at video frequency. Among the 7 photodetections performed in the tracheobronchial tree, 6 were successful, whereas it was the case for only 5 of the 15 lesions investigated in squamous mucosa (upper aerodigestive tract and esophagus). The sources of false positives and false negatives are evaluated in terms of the fluorescent dye, tissue optical properties, and illumination optics.

In vivo autofluorescence spectroscopy of human bronchial tissue to optimize the detection and imaging of early cancers

“…The Pentax system works with a single range detection principle, 20 whereas a multiple range approach has been preferred for the Xillix and the Storz systems 19,32 and some laboratory systems. 8,17,18 It is interesting to note that our results are in good agreement with these previous results. Indeed, we also found that the autofluorescence of the early cancerous lesions sharply decreases when excited in the blue-violet range and decreases less significantly in the red region.…”

“…However, the changes occurring during the first stages of the cancerization process make it difficult in most cases for the endoscopist to accurately localize the lesions under white light illumination. Several examples of the use of light-induced fluorescence ͑LIF͒ have been proposed for point fluorescence measurements and imaging applications with [4][5][6][7][8] and without 4,[9][10][11][12][13][14][15] the addition of an exogenous drug to enhance the contrast between the early cancerous lesion and the healthy surrounding area. 16 Because they rely upon the natural fluorescence of the tissues, the latter are termed ''autofluorescence'' methods.…”

“…In this paper, we are thus reporting on a study about the autofluorescence of the bronchial tissue. Several experimental 8,17,18 and commercially available systems ͑Xillix, 10,11 Storz, 19 SAFE-1000 ͑Pentax͒, 20 ͒ use autofluorescence to create images of the bronchial tissue. The goal of these systems is to detect and distinguish the precancerous and early cancerous lesions from the healthy surrounding area.…”

“…To do so, most of these systems excite the autofluorescence with blue and/or violet light and detect the autofluorescence in one, 20 or several spectral regions. 8,10,11,19 However, no systematic optimization work has been reported for the spectral design of these systems. Improvement might be possible by optimizing the domains of excitation and detection wavelengths.…”

Wavelet-based characterization of spectral fluctuations in normal, benign, and cancerous human breast tissues

“…Over the past 15 years its diagnostic potential has been tested in different organs of the body, including the mouth, breast, esophagus, and bladder, etc. [9][10][11][12][13][14][15][16][17] Diagnosis of human breast cancer through fluorescence studies has been an active area of research for quite some time. Although more than 80% of breast lumps are not cancerous, biopsy is the only way to diagnose.…”