Potential and Current Uses of Luminescence in Medical Diagnosis

Abstract

Biological luminescence stimulated by optical excitation results in signals which are characteristic of the host tissue. The spectrum of the emitted light, the intensity, and the excited state lifetimes are modified as the result of disease or by activation through addition of cell selective phosphors. There is an opportunity to identify diseased tissue both by the spectral signals from activators or, in some cases, by the differences of the natural luminescence responses. For practical reasons, defined by the sensitivity range of standard luminescence detectors, much of the current work has focussed on the short wavelength emissions driven by laser activation. However, the techniques are poised to undergo a dramatic expansion in scope with the advent of higher sensitivity photocathodes with high efficiency responses at long wavelengths. It is now possible to utilise a greater range of emission features with improved discrimination. Further, movement to longer wavelength excitation, and emission, open the way to probe deeper beneath the surface of tissue. The current overview will focus on recent examples from detection of cancer to tooth caries and indicate how the non-destructive luminescence probes can distinguish between tissue changes at an early stage of development.

Biophysical characterization of human breast tissues by photoluminescence excitation-emission spectroscopy

“…Modern medicine is constantly looking for more accurate diagnostic techniques. Those based on optical spectroscopy, called "optical biopsy", had made a giant step on the field of early cancer detection [3][4][5]. Very important properties of these techniques are speed, non invasiveness, reliability and high sensitivity.…”

Laser induced autofluorescence studies of animal skin used in modeling of human cutaneous tissue spectroscopic measurements

“…Nitrogen laser (337.1 nm), helium–cadmium laser (442 nm) and argon‐ion laser (488 nm, 514 nm) are used commonly as laser excitation sources (1–3, 7). Recently with the fast development of semiconductor technologies, ultraviolet and blue light emitting diodes, with narrow spectral width and high power, appear in the market and are also applied for bioluminescence purposes (4). However, the excitation wavelength around 340 nm, is found as optimal for inducing autofluorescence from endogenous chromophores (25, 26).…”

“…The laser-induced fluorescence spectroscopy detection gives a possibility for real-time, non-invasive diagnosis of tumors ('optical biopsy') and other tissue pathologies, e.g. atherosclerosis (2)(3)(4)(5)(6).…”

Laser- and Light-Induced Autofluorescence Spectroscopy of Human Skin in Dependence on Excitation Wavelengths

“…With increase in knowledge about optical properties of different tissues and their pathologies, as well as with the improvement of spectroscopic equipment and the optimization of measurement methodologies new diagnostic approaches are introduced for the medical diagnosis purposes [1][2][3][4].…”