Comparison of spatially and temporally resolved diffuse-reflectance measurement systems for determination of biomedical optical properties.
Time-resolved and spatially resolved measurements of the diffuse reflectance from biological tissue are two well-established techniques for extracting the reduced scattering and absorption coefficients. We have performed a comparison study of the performance of a spatially resolved and a time-resolved instrument at wavelengths 660 and 786 nm and also of an integrating-sphere setup at 550-800 nm. The first system records the diffuse reflectance from a diode laser by means of a fiber bundle probe in contact with the sample. The time-resolved system utilizes picosecond laser pulses and a single-photon-counting detection scheme. We extracted the optical properties by calibration using known standards for the spatially resolved system, by fitting to the diffusion equation for the time-resolved system, and by using an inverse Monte Carlo model for the integrating sphere. The measurements were performed on a set of solid epoxy tissue phantoms. The results showed less than 10% difference in the evaluation of the reduced scattering coefficient among the systems for the phantoms in the range 9-20 cm(-1), and absolute differences of less than 0.05 cm(-1) for the absorption coefficient in the interval 0.05-0.30 cm(-1).
Swartling
Johannes
J
Department of Physics, Lund Institute of Technology, P.O. Box 118, SE-22100 Lund, Sweden. johannes.swartling@fysik.lth.se
Dam
Jan S
JS
Andersson-Engels
Stefan
S
D000818:Animals; D020811:Biomedical Technology; D008460:Meat; D055095:Optics and Photonics; D019047:Phantoms, Imaging; D012542:Scattering, Radiation; D013552:Swine; D013997:Time Factors