Optical properties of biological tissues: a review (original) (raw)
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Optical Reflectance and Transmittance of Tissues: Principles and Applications
This paper presents a discussion of diagnostic and dosi-metric optical measurements in medicine and biology. The introduction covers the topics of tissue optical properties, tissue boundary conditions , and invasive versus noninvasive measurements. Clinical applications of therapeutic dosimetry and diagnostic spectroscopy are discussed. The principles of diffuse reflectance and transmittance measurements are presented. Experimental studies illustrate reflectance spectroscopy and steady-state versus time-resolved measurements.
Optics of living tissues with controlled scattering properties
Proceedings of SPIE - The International Society for Optical Engineering
Results of in vitro and in vivo experimental studies of the optical properties of the rabbit eye, the human eye sclera, and the human skin controlled by administration of osmotically active chemicals, such as glucose, trazograph, and the 50% -Glycerol + DMSO solution are presented. Glucose and other solutions administration induces the diffusion of matter and as a result the equalization of the refractive indices of collagen fibrils and ground material, and corresponding changes of reflectance and transmittance spectra of living tissue. Transmittance and reflectance spectra measurements of tissues, as well as optical anisotropy determination using color measurements were provided. The diffusion coefficient for glucose within scleral tissue was estimated; the average value is 6 6 10 64 . 1 10 62 . 5 − − ⋅ ± ⋅
Optical properties of peritoneal biological tissues in the spectral range of 350–2500 nm
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The optical characteristics of biological tissues sampled from the anterior abdominal wall of laboratory rats are for the first time experimentally studied in a wide wavelength range (350-2500 nm). The experiments have been performed in vitro using a LAMBDA 950 (PerkinElmer, United States) spectrophotometer. Inverse Monte Carlo simulation is used to restore the spectral dependences for scattering and absorption coefficients, as well as the scattering anisotropy factor for biological tissue based on the recorded spectra of diffuse reflection and total and collimated transmissions.
Optics Express, 2008
A novel, multi-wavelength, fiberoptic system was constructed, evaluated and implemented to determine internal tissue optical properties at ultraviolet A (UVA) and visible (VIS) wavelengths. Inverse modeling was performed with a neural network to estimate absorption and reduced scattering coefficients based on spatially-resolved reflectance distributions. The model was calibrated with simulated reflectance datasets generated using a condensed Monte Carlo approach with absorption coefficients up to 85 cm -1 and reduced scattering coefficients up to 118 cm -1 . After theoretical and experimental evaluations of the system, optical properties of porcine bladder, colon, esophagus, oral mucosa, and liver were measured at 325, 375, 405, 445 and 532 nm. These data provide evidence that as wavelengths decrease into the UVA, the dominant tissue chromophore shifts from hemoglobin to structural proteins such as collagen. This system provides a high level of accuracy over a wide range of optical properties, and should be particularly useful for in situ characterization of highly attenuating biological tissues in the UVA-VIS.
Bulk optical properties of healthy female breast tissue
2002
Abstract We have measured the bulk optical properties of healthy female breast tissues in vivo in the parallel plate, transmission geometry. Fifty-two volunteers were measured. Blood volume and blood oxygen saturation were derived from the optical property data using a novel method that employed a priori spectral information to overcome limitations associated with simple homogeneous tissue models. The measurements provide an estimate of the variation of normal breast tissue optical properties in a fairly large population.
Reflectance-based determination of optical properties in highly attenuating tissue
Journal of Biomedical Optics, 2003
Accurate data on in vivo tissue optical properties in the ultraviolet A (UVA) to visible (VIS) range are needed to elucidate light propagation effects and to aid in identifying safe exposure limits for biomedical optical spectroscopy. We have performed a preliminary study toward the development of a diffuse reflectance system with maximum fiber separation distance of less than 2.5 mm. The ultimate objective is to perform endoscopic measurement of optical properties in the UVA to VIS. Optical property sets with uniformly and randomly distributed values were developed within the range of interest: absorption coefficients from 1 to 25 cm −1 and reduced scattering coefficients from 5 to 25 cm −1. Reflectance datasets were generated by direct measurement of Intralipid-dye tissue phantoms at =675 nm and Monte Carlo simulation of light propagation. Multivariate calibration models were generated using feed-forward artificial neural network or partial least squares algorithms. Models were calibrated and evaluated using simulated or measured reflectance datasets. The most accurate models developed-those based on a neural network and uniform optical property intervals-were able to determine absorption and reduced scattering coefficients with root mean square errors of Ϯ2 and Ϯ3 cm −1 , respectively. Measurements of ex vivo bovine liver at 543 and 633 nm were within 5 to 30% of values reported in the literature. While our technique for determination of optical properties appears feasible and moderately accurate, enhanced accuracy may be achieved through modification of the experimental system and processing algorithms.
A review of in-vivo optical properties of human tissues and its impact on PDT
Journal of Biophotonics, 2011
A thorough understanding of optical properties of biological tissues is critical to effective treatment planning for therapies such as photodynamic therapy (PDT). In the last two decades, new technologies, such as broadband diffuse spectroscopy, have been developed to obtain in vivo data in humans that was not possible before. We found that the in vivo optical properties generally vary in the ranges μ a =0.03-1.6 cm −1 and μ s '=1.2-40 cm −1 , although the actual range is tissuetype dependent. We have also examined the overall trend of the absorption spectra (for μ a and μ s ') as a function of wavelength within a 95% confidence interval for various tissues in vivo. The impact of optical properties on light fluence rate is also discussed for various light application geometries including superficial, interstitial, and within a cavity.
Study of Scattering and Polarization of Light in Biological Tissues
2013
INTRODUCTION 1.1 State of-the-art 1.2 Objectives of the dissertation 2 SELECTED METHODS OF INVESTIGATION 2.1 Modeling of photon transport in tissue 9 2.1.1 Radiative transfer equation 3 EXPERIMENTAL RESULTS 3.1 Stokes vector polarimeter 3.2 Monte Carlo analysis of multiscattered light 3.2.1 Intensity and degree of polarization 3.2 Ageing process 4 CONCLUSION 5 REFERENCES