Determination of visible near-IR absorption coefficients of mammalian fat using time- and spatially resolved diffuse reflectance and transmission spectroscopy

2005 ◽  
Vol 10 (5) ◽  
pp. 054004 ◽  
Author(s):  
R. L. P. van Veen ◽  
H. J. C. M. Sterenborg ◽  
A. Pifferi ◽  
A. Torricelli ◽  
E. Chikoidze ◽  
...  
Keyword(s):  
Diffuse Reflectance ◽  
Ir Absorption ◽  
Absorption Coefficients ◽  
Spatially Resolved ◽  
Near Ir ◽  
Transmission Spectroscopy

Simultaneous Determination of Absorption Coefficients for Skin and Muscle Tissues Using Spatially Resolved Measurements

2011 ◽  
Vol 222 ◽  
pp. 309-312 ◽  
Author(s):  
Hiroshi Suzuki ◽  
Masatsugu Niwayama ◽  
Toshitaka Yamakawa ◽  
Masaki Ohkubo ◽  
Ryotaro Kime ◽  
...  
Keyword(s):  
Near Infrared ◽  
Absorption Coefficients ◽  
Calculation Algorithm ◽  
Spatially Resolved ◽  
Muscle Tissues ◽  
In Vivo Tests ◽  
Deep Layers

We present a method for simultaneous measurement of optical absorption coefficients for skin (μas) and muscle (μam) tissues using spatially resolved near-infrared spectroscopy (SRS). A novel calculation algorithm was developed to determine the absorption coefficients of superficial and deep layers within a three-layered structure using Monte Carlo simulation. A method for measuring the skin and muscle absorption coefficients was proposed based on this algorithm. In vitro experiments with tissue-like phantom and in vivo tests were performed using the SRS system with four separate detectors. The results show that the absorption coefficients for both skin and muscle tissues were obtained accurately.

Quantitative Determination of the Scattering and Absorption Coefficients from Diffuse Reflectance and Transmittance Measurements: Application to Pharmaceutical Powders

1997 ◽  
Vol 51 (3) ◽  
pp. 309-317 ◽  
Author(s):  
T. Burger ◽  
J. Kuhn ◽  
R. Caps ◽  
J. Fricke
Keyword(s):  
Particle Size ◽  
Diffuse Reflectance ◽  
Pharmaceutical Powders ◽  
Separate Determination ◽  
Absorption Coefficients ◽  
Absorption Properties ◽  
Flux Approximation ◽  
Reflectance Measurements ◽  
Made In

A measurement and data evaluation technique for the separate determination of the scattering and absorption properties of loose pharmaceutical powders is described. The equation of radiative transfer for diffuse reflectance and transmittance is analytically solved by using a three-flux approximation. Combined transmittance and reflectance measurements then allow one to derive both the scattering and the absorption coefficients. The scattering and absorption coefficients provide more information about particle size, degree of agglomeration, and chemical composition of the samples in comparison to the usual determination of only the ratio of the coefficients from diffuse reflectance measurements on optically thick samples. Furthermore, the theory of diffuse reflectance of optically thick samples according to Kubelka and Munk is compared to the three-flux approximation. The influence of the particle size on the scattering and absorption coefficient is investigated, and it is shown that the assumption of a wavelength-independent scattering coefficient, though often made in reflectance spectroscopy, is not generally valid.

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