Extraction of intrinsic fluorescence from single fiber fluorescence measurements on a turbid medium: experimental validation.
U A Gamm, C L Hoy, F van Leeuwen-van Zaane, H J C M Sterenborg, S C Kanick, D J Robinson, A Amelink
Author Information
U A Gamm: Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
C L Hoy: Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
F van Leeuwen-van Zaane: Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
H J C M Sterenborg: Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
S C Kanick: Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, New Hampshire 03755, USA.
D J Robinson: Department of Otorhinolaryngology-Head and Neck Surgery, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
A Amelink: Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
The detailed mechanisms associated with the influence of scattering and absorption properties on the fluorescence intensity sampled by a single optical fiber have recently been elucidated based on Monte Carlo simulated data. Here we develop an experimental single fiber fluorescence (SFF) spectroscopy setup and validate the Monte Carlo data and semi-empirical model equation that describes the SFF signal as a function of scattering. We present a calibration procedure that corrects the SFF signal for all system-related, wavelength dependent transmission efficiencies to yield an absolute value of intrinsic fluorescence. The validity of the Monte Carlo data and semi-empirical model is demonstrated using a set of fluorescent phantoms with varying concentrations of Intralipid to vary the scattering properties, yielding a wide range of reduced scattering coefficients (μ's = 0-7 mm (-1)). We also introduce a small modification to the model to account for the case of μ's = 0 mm (-1) and show its relation to the experimental, simulated and theoretically calculated value of SFF intensity in the absence of scattering. Finally, we show that our method is also accurate in the presence of absorbers by performing measurements on phantoms containing red blood cells and correcting for their absorption properties.
