Optical biopsy - a new armamentarium to detect disease using light

Abstract

Optical spectroscopy has been considered a promising method for cancer detection for past thirty years because of its advantages over the conventional diagnostic methods of no tissue removal, minimal invasiveness, rapid diagnoses, less time consumption and reproducibility since the first use in 1984. It offers a new armamentarium. Human tissue is mainly composed of extracellular matrix of collagen fiber, proteins, fat, water, and epithelial cells with key molecules in different structures. Tissues contain a number of key fingerprint native endogenous fluorophore molecules, such as tryptophan, collagen, elastin, reduced nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD) and porphyrins. It is well known that abnormalities in metabolic activity precede the onset of a lot of main diseases: carcinoma, diabetes mellitus, atherosclerosis, Alzheimer, and Parkinson's disease, etc. Optical spectroscopy may help in detecting various disorders. Conceivably the biochemical or morphologic changes that cause the spectra variations would appear earlier than the histological aberration. Therefore, "optical biopsy" holds a great promise as clinical tool for diagnosing early stage of carcinomas and other deceases by combining with available photonic technology (e.g. optical fibers, photon detectors, spectrographs spectroscopic ratiometer, fiber-optic endomicroscope and nasopharyngoscope) for in vivo use. This paper focuses on various methods available to detect spectroscopic changes in tissues, for example to distinguish cancerous prostate tissues and/or cells from normal prostate tissues and/or cells. The methods to be described are fluorescence, stokes shift, scattering, Raman, and time-resolved spectroscopy will be reviewed. The underlying physical and biological basis for these optical approaches will be discussed with examples. The idea is to present some of the salient works to show the usefulness and methods of Optical Biopsy for cancer detection and show new directions.

Fluorescence biomarkers of malignant melanoma detectable in urine

“…MM is one of the most aggressive forms of cancer. Neoplastic changes in skin cells are predominantly due to physical damage, such as an inappropriate exposure to UV radiation (mainly UVc) [44], which damages the genetic information of healthy melanocytes and leads to tumour transformation (UVb radiation is required to activate provitamin D in the dermis). Repeated sunburn caused by inadequate exposure to sunlight, and therefore UV radiation, increases the risk of MM.…”

Discrimination and quantification of autofluorescence spectra of human lung cells

“…A plaque in the bronchial epithelium is too difficult to be diagnosed in situ due to the thin layer of cells, which is about 10 cells-in millimeter ranges-across [1][2][3]. Because of the lack of in situ, high resolution, fast and noninvasive diagnostic methods, optical biopsy is a promising technique for in vitro and in vivo cancer detection [4]. In recent years autofluorescence spectroscopy or native fluorescence spectroscopy is one of the optical biopsy methods that has drawn attention for studying generally cell biology and, in particular, cell metabolism, cell membrane, protein and DNA structure in cancer diagnosis.…”