Frequency-domain reflectance for the determination of the scattering and absorption properties of tissue

Patterson, Michael S.; Moulton, J. David; Wilson, Brian C.; Berndt, Klaus W.; Lakowicz, Joseph R.

doi:10.1364/ao.30.004474

Cited by 219 publications

(113 citation statements)

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“…Because absorption and scattering are interwoven during light transfer in turbid media, fast and accurate measurement of the absorption and scattering coefficients still remains a challenging task. Over the years, researchers in the field of biomedical optics have developed several techniques for measuring the optical properties of biological tissues, which, according to their measurement principles, can be categorized into: time-resolved [93,94], frequency domain [95,96], spatially-resolved [56,97], and spatial frequency domain [98,99]. While time-resolved and frequency domain techniques are able to interrogate the tissues at a greater depth, they generally require more expensive and sophisticated instrumentation and have fewer wavelength selection options.…”

Section: Spatially-resolved Spectroscopic Technique For Optical Propementioning

confidence: 99%

Innovative Hyperspectral Imaging-Based Techniques for Quality Evaluation of Fruits and Vegetables: A Review

Huang

2017

Applied Sciences

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New, non-destructive sensing techniques for fast and more effective quality assessment of fruits and vegetables are needed to meet the ever-increasing consumer demand for better, more consistent and safer food products. Over the past 15 years, hyperspectral imaging has emerged as a new generation of sensing technology for non-destructive food quality and safety evaluation, because it integrates the major features of imaging and spectroscopy, thus enabling the acquisition of both spectral and spatial information from an object simultaneously. This paper first provides a brief overview of hyperspectral imaging configurations and common sensing modes used for food quality and safety evaluation. The paper is, however, focused on the three innovative hyperspectral imaging-based techniques or sensing platforms, i.e., spectral scattering, integrated reflectance and transmittance, and spatially-resolved spectroscopy, which have been developed in our laboratory for property and quality evaluation of fruits, vegetables and other food products. The basic principle and instrumentation of each technique are described, followed by the mathematical methods for processing and extracting critical information from the acquired data. Applications of these techniques for property and quality evaluation of fruits and vegetables are then presented. Finally, concluding remarks are given on future research needs to move forward these hyperspectral imaging techniques.

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Section: Spatially-resolved Spectroscopic Technique For Optical Propementioning

confidence: 99%

Innovative Hyperspectral Imaging-Based Techniques for Quality Evaluation of Fruits and Vegetables: A Review

Huang

2017

Applied Sciences

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“…30 To accurately quantify tissue properties, the effects of light absorption and scatter on photon migration must be separated by either time or frequency domain measurements. 31,32 By operating within a MR scanner, images may be formed with increased accuracy and spatial resolution 33 through the incorporation of prior knowledge of tissue boundaries, similar to one way in which computed tomography aids PET by providing structural details. 34 The MR-guided optical imaging instrument used in this work is shown in Fig.…”

Section: Iia Mr-guided Diffuse Optical Imagingmentioning

confidence: 99%

Monitoring of hemodynamic changes induced in the healthy breast through inspired gas stimuli with MR-guided diffuse optical imaging

et al. 2010

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Purpose: The modulation of tissue hemodynamics has important clinical value in medicine for both tumor diagnosis and therapy. As an oncological tool, increasing tissue oxygenation via modulation of inspired gas has been proposed as a method to improve cancer therapy and determine radiation sensitivity. As a radiological tool, inducing changes in tissue total hemoglobin may provide a means to detect and characterize malignant tumors by providing information about tissue vascular function. The ability to change and measure tissue hemoglobin and oxygenation concentrations in the healthy breast during administration of three different types of modulated gas stimuli (oxygen/carbogen, air/carbogen, and air/oxygen) was investigated. Methods: Subjects breathed combinations of gases which were modulated in time. MR‐guided diffuse optical tomography measured total hemoglobin and oxygen saturation in the breast every 30 s during the 16 min breathing stimulus. Metrics of maximum correlation and phase lag were calculated by cross correlating the measured hemodynamics with the stimulus. These results were compared to an air/air control to determine the hemodynamic changes compared to the baseline physiology. Results: This study demonstrated that a gas stimulus consisting of alternating oxygen/carbogen induced the largest and most robust hemodynamic response in healthy breast parenchyma relative to the changes that occurred during the breathing of room air. This stimulus caused increases in total hemoglobin and oxygen saturation during the carbogen phase of gas inhalation, and decreases during the oxygen phase. These findings are consistent with the theory that oxygen acts as a vasoconstrictor, while carbogen acts as a vasodilator. However, difficulties in inducing a consistent change in tissue hemoglobin and oxygenation were observed because of variability in intersubject physiology, especially during the air/oxygen or air/carbogen modulated breathing protocols. Conclusions: MR‐guided diffuse optical imaging is a unique tool that can measure tissue hemodynamics in the breast during modulated breathing. This technique may have utility in determining the therapeutic potential of pretreatment tissue oxygenation or in investigating vascular function. Future gas modulation studies in the breast should use a combination of oxygen and carbogen as the functional stimulus. Additionally, control measures of subject physiology during air breathing are critical for robust measurements.

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“…In this work, we also discuss the limiting phase velocity of the photon density wave predicted by the (2) is the diffusion coefficient (with units of distance), (3) is the reduced scattering coefficient (with units of inverse distance), g is the average of the cosine of the scattering angle after a photon collision, and p, and p"respectively, are the inverse of the mean-free path for photon absorption and the inverse of the mean-free path for elastic scattering collisions (p, and p, have units of inverse distance). S' '(r, t) is the photon source, with qo(r, t) being the isotropic term in a first-order spherical harmonics expansion of the source term in the Boltzmann transport equation, and q, (r, t) is the first moment in this expansion which describes the dipole-like anisotropy of the source.…”

Section: Introductionmentioning

confidence: 99%

Gigahertz photon density waves in a turbid medium: Theory and experiments

et al. 1996

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The predictions of the frequency-domain standard diffusion equation (SDE) model for light propagation in an infinite turbid medium diverge from the more complete P& approxI'matron to the linear Boltzmann transport equation at intensity modulation frequencies greater than several hundred MHz.The P& approximation is based on keeping only the terms 1=0 and 1=1 in the expansion of the angular photon density in spherical harmonics, and the nomenclature P& approximation is used since the spherical harmonics of order 1=1 can be written in terms of the first order Legendre polynomial, which is traditionally represented by the symbol P&. Frequency-domain data acquired in a quasi-infinite turbid medium at modulation frequencies ranging from 0.38 to 3.2 GHz using a superheterodyning microwave detection system were analyzed using expressions derived from both the P& aproximation equation and the SDE. This analysis shows that the P& approximation provides a more accurate description of the data over this range of modulation frequencies. Some researchers have claimed that the P& approximation predicts that a light pulse should propagate with an average speed of c/&3 in a thick turbid medium. However, an examination of the Green's function that we obtained from the frequency-domain P, approximation model indicates that a photon density wave phase velocity of c/&3 is only asymptotically approached in a regime where the light intensity modulation frequency aproaches infinity. The Fourier transform of this frequency-domain result shows that in the time domain, the P & approximation predicts that only the leading edge of the pulse {i. e. , the photons arriving at the detector at the earliest time) approaches a speed of c /+3. PACS number(s): 05.60.+w

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Frequency-domain reflectance for the determination of the scattering and absorption properties of tissue

Abstract: Measurements of the phase and modulation of amplitudemodulated light diffusely reflected by turbid media can be used to deduce absorption and scattering coefficients.

Cited by 219 publications

References 3 publications

Innovative Hyperspectral Imaging-Based Techniques for Quality Evaluation of Fruits and Vegetables: A Review

Innovative Hyperspectral Imaging-Based Techniques for Quality Evaluation of Fruits and Vegetables: A Review

Monitoring of hemodynamic changes induced in the healthy breast through inspired gas stimuli with MR-guided diffuse optical imaging

Gigahertz photon density waves in a turbid medium: Theory and experiments

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