Journal ArticleDOI
Influence of overlying tissue and probe geometry on the sensitivity of a near-infrared tissue oximeter
TLDR
The Monte Carlo simulation results showed that the sensitivity of the near infrared spectroscopy (NIRS) oximeter declined greatly with increasing overlying tissue thickness, and increasing the distance between the light source and the detector improved the sensitivity.Abstract:
In this paper, the influences of overlying tissue and detecting distance between the source and the detector on the measurement of a tissue oximeter were discussed. The signal-noise-ratio of the detector was also examined. A semi-infinite multi-layer Monte Carlo model was induced to simulate the migration of the photons in the skin, adipose and muscle. The thickness of the adipose layer and the separation between the source and the detector in the muscle were changed to simulate the clinical application. Partial pathlength was introduced as a characteristic parameter to evaluate the sensitivity of the oximeter. A two-wavelength (700 and 830 nm) tissue oximeter was developed to verify the results of the simulation. The Monte Carlo simulation results showed that the sensitivity of the near infrared spectroscopy (NIRS) oximeter declined greatly with increasing overlying tissue thickness. Increasing the distance between the light source and the detector improved the sensitivity. However, in order to achieve a sufficiently high signal-to-noise ratio, it was necessary to limit this distance. The results of a bicycle ergometer exercise verified the above results and showed that, for a special adipose thickness (AT), there may be a reasonable range of the emitter-detector separation.read more
Citations
More filters
Journal ArticleDOI
Optical coherence tomography - principles and applications
TL;DR: OCT as discussed by the authors synthesises cross-sectional images from a series of laterally adjacent depth-scans, which can be used to assess tissue and cell function and morphology in situ.
Journal ArticleDOI
Mobile monitoring with wearable photoplethysmographic biosensors
TL;DR: The ring sensor is an ambulatory, telemetric, continuous health-monitoring device that combines miniaturized data acquisition features with advanced photoplethysmographic techniques to acquire data related to the patient's cardiovascular state using a method far superior to existing fingertip PPG sensors.
Journal ArticleDOI
Utility of the photoplethysmogram in circulatory monitoring.
TL;DR: Overall, the photoplethysmogram provides a wealth of circulatory information, but its complex etiology may be a limitation in some novel applications.
Journal ArticleDOI
Ultrahigh sensitive optical microangiography for in vivo imaging of microcirculations within human skin tissue beds.
Lin An,Jia Qin,Ruikang K. Wang +2 more
TL;DR: It is demonstrated for the first time that the detailed cutaneous blood flow at capillary level within dermis of human skin can be imaged by optical micro-angiography (OMAG) technique.
Journal ArticleDOI
Microvascular imaging: techniques and opportunities for clinical physiological measurements
John F. Allen,Kevin Howell +1 more
TL;DR: The wide variety of methods now available for imaging of the microvasculature and their key applications are described, with a clinical focus, to show their potential as techniques that could become established tools for clinical microvascular assessment.
References
More filters
Journal ArticleDOI
A review of the optical properties of biological tissues
TL;DR: The known optical properties (absorption, scattering, total attenuation, effective attenuation and/or anisotropy coefficients) of various biological tissues at a variety of wavelengths are reviewed in this article.
Journal ArticleDOI
Performance comparison of several published tissue near-infrared spectroscopy algorithms
TL;DR: Multiwavelength near-infrared attenuation spectra on human forearm muscle, the adult rat head, and newborn piglet head are collected to compare the changes in chromophore concentration derived from these data using published algorithms from four groups, finding differences between the results from the algorithms on each data set.
Journal ArticleDOI
Optical properties of human dermis in vitro and in vivo
TL;DR: The in vivo values for the absorption coefficients and the reduced scattering coefficients appear to be much smaller than the values from the in vitro measurements, that have been assumed until now.
Journal ArticleDOI
Influence of a superficial layer in the quantitative spectroscopic study of strongly scattering media.
TL;DR: It is found that the measured effective optical coefficients are representative of the underlying block if the superficial layer is less than ~0.4 cm thick, whereas they are Representative of the superficiallayer if it is more than ~1.3 cm thick.
Journal ArticleDOI
Measuring absorption coefficients in small volumes of highly scattering media: source-detector separations for which path lengths do not depend on scattering properties
TL;DR: It is demonstrated, using both Monte Carlo simulations and experimental measurements, that for an appropriate separation between light-delivery and light-collection fibers the path length of the collected photons does not depend on scattering parameters for the range of parameters typically found in tissue.