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Measurement of time‐resolved autofluorescence
Author(s) -
SCHWEITZER D,
SCHENKE S,
JENTSCH S,
QUICK S,
GEHLERT S,
HAMMER M,
BERGMANN N
Publication year - 2008
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2008.5312.x
Subject(s) - autofluorescence , fluorescence , picosecond , fluorescence lifetime imaging microscopy , excitation , optics , emission spectrum , chemistry , laser , nuclear magnetic resonance , materials science , spectral line , physics , quantum mechanics , astronomy
Purpose Functional alterations are first signs of reversible pathologic processes. Whereas microcirculation studies metabolism globally, autofluorescence of endogenous fluorophores has the potential for description of cellular basic processes. Therefore, a discrimination of fluorophores is required in the tissue. Methods Besides excitation and emission spectra, the fluorescence lifetime after short‐time excitation is a promising substance‐specific mark. Using the opto‐mechanical system of a HRA II (Heidelberg Engineering), a fluorescence lifetime mapper was developed. Picosecond pulse‐lasers (448nm, 468nm, 100ps FWHM, 80MHz) can be used for excitation and the emission will be detected in 2 spectral ranges (490‐560nm, 560‐700nm). The dynamic fluorescence will be detected in time‐correlated single photon counting (SPC 150, Becker/Hickl, Berlin). An on line image registration is realised by simultaneously detected infrared images during measuring time. Approximating the fluorescence decay by 3‐exponential model function, images (lifetime and amplitudes), histograms, and cluster diagrams can be calculated for interpretation. Results Examples are given for healthy subjects, AMD patients (non‐exudative, exudative, geographic atrophy), diabetic retinopathy, and oedema. Measurements of excitation and emission spectra as well as lifetimes are performed of expected substances and of anatomical ocular structures for comparison. Conclusion Fluorescence lifetime measurement at the eye is a new method for evaluation of functional metabolic state.