We developed a compact dual-wavelength multichannel tissue oximeter based on the time-correlated single-photon counting (TCSPC) technique. The light sources are two pulsed diode lasers (output wavelengths of 672 and 818 nm, an average power of 1 mW, a pulse duration of 100 ps, and a pulse-repetition rate as high as 80 MHz). The time-resolved reflectance photons are detected by a multianode photomultiplier, and the output signals are redirected by a router to different memory blocks of the TCSPC personal computer board. The system’s accuracy in determining the absorption μ<sub><i>a</i></sub> and the reduced-scattering μ<sub><i>s</i></sub>′ coefficients and in reconstructing absorber concentrations in diffusive media was tested on phantoms. Preliminary <i>in vivo</i> tissue-oxygenation measurements were performed on healthy volunteers under different physiological conditions with a minimum acquisition time of 100 ms and an injected power of less than 100 μW.
© 1999 Optical Society of America
(170.1470) Medical optics and biotechnology : Blood or tissue constituent monitoring
(170.5280) Medical optics and biotechnology : Photon migration
(170.6510) Medical optics and biotechnology : Spectroscopy, tissue diagnostics
(300.6500) Spectroscopy : Spectroscopy, time-resolved
Rinaldo Cubeddu, Antonio Pifferi, Paola Taroni, Alessandro Torricelli, and Gianluca Valentini, "Compact Tissue Oximeter Based on Dual-Wavelength Multichannel Time-Resolved Reflectance," Appl. Opt. 38, 3670-3680 (1999)