共查询到20条相似文献,搜索用时 15 毫秒
1.
Non-invasive glucose sensing with near-infrared spectroscopy enhanced by optical measurement conditions reproduction technique 总被引:1,自引:0,他引:1
Kexin Xu Qingjun Qiu Jingying Jiang Xiuyan Yang 《Optics and Lasers in Engineering》2005,43(10):1096-1106
Non-invasive glucose sensing utilizing near-infrared spectroscopy (NIRS) has been a focusing topic in biomedical optics applications. However, different probing locations and contact pressures between the probe and skin cause variations in the light propagation paths within tissue, making it very hard to obtain stable near-infrared spectra concerning body content. This paper proposes one possible solution to the reproduction of light propagation within tissue for near-infrared non-invasive glucose sensing systems by introducing the optical measurement conditions reproduction technique. Results of experiments on glucose concentrations within human body through application of our proposed system show a RMSEP value of 15–20 mg/dL and a correlation coefficient greater than 0.8. 相似文献
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We present a novel implementation of high-resolution ultrasound-modulated optical tomography that, based on optical contrast, can image several millimeters deep into soft biological tissues. A long-cavity confocal Fabry-Perot interferometer, which provides a large etendue and a short response time, was used to detect the ultrasound-modulated coherent light that traversed the scattering biological tissue. Using 15-MHz ultrasound, we imaged with high-contrast light-absorbing structures placed >3 mm below the surface of chicken breast tissue. The resolution along the axial and the lateral directions with respect to the ultrasound propagation direction was better than 70 and 120 microm, respectively. The resolution can be scaled down further by use of higher ultrasound frequencies. This technology is complementary to other imaging technologies, such as confocal microscopy and optical-coherence tomography, and has the potential for broad biomedical applications. 相似文献
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The measurement of the blood glucose level utilizing the optical nonlinearity observed by a single-optical beam Z-scan technique is proposed. The glucose level is calculated by measuring the nonlinear refractive index (n 2) of the sample. The results are compared with the measurement made by the conventional colorimetric method and are found to be in good agreement. 相似文献
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A novel frequency-swept ultrasound-modulated optical tomography technique was developed to image scattering media. A frequency-swept ultrasonic wave was used to modulate the laser light passing through a scattering medium. The modulated light was received by an optical detector and was heterodyned with a reference frequency sweep. The heterodyned signal was recorded in the time domain and was then analyzed in the frequency domain to yield a one-dimensional image along the ultrasonic axis. Multiple one-dimensional images obtained at various positions perpendicular to the ultrasonic axis were combined to yield a two-dimensional tomographic image of the medium. 相似文献
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We have proposed a tested in tissue phantoms and in vivo a novel sensor based on optical coherence tomography (OCT) for noninvasive and continuous monitoring of blood glucose concentration. OCT images were obtained from pig and rabbit skin before and after glucose administration. Slopes of OCT signals decreased substantially (~40% in tissues in vivo) and linearly with the increase of blood glucose concentration from 4 to 30 mM, typical for normal and diabetic subjects. Phantom studies demonstrated 1% accuracy of scattering-coefficient measurement. Our theoretical and experimental studies suggest that glucose concentration can potentially be measured noninvasively with high sensitivity and accuracy with OCT systems. 相似文献
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We used multiple optical wavelengths to study ultrasound-modulated optical tomography (UOT) in tissue phantoms. By using intense acoustic bursts and a CCD camera-based speckle contrast detection technique, we observed variations of the ultrasound-modulated signal at various optical absorptions. The experimental variations were found to be highly correlated with predictions from Monte Carlo simulations. By irradiating the sample at two optical wavelengths, we quantitatively estimated the total concentration and the concentration ratio of double dyes in objects embedded in tissue phantoms. The results suggest that UOT can potentially provide noninvasive functional imaging of the total concentration and oxygen saturation of hemoglobin in biological tissue. 相似文献
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In this paper, our investigations suggest that the modulation phase of ultrasound-modulated light escaping from the different locations in the ultrasonic field is different. In turbid media, the modulation phase causes the ultrasound-modulated light intensity collected outside the media to fluctuate. However, the ultrasound-modulated optical technology uses the ultrasound-modulated light signals to image. Consequently, the modulation phase affects the quality of ultrasound-modulated optical imaging. 相似文献
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We show the feasibility of imaging objects having different optical scattering coefficients relative to the surrounding scattering medium using ultrasound-modulated optical tomography (UOT). While the spatial resolution depends on ultrasound parameters, the image contrast depends on the difference in scattering coefficient between the object and the surrounding medium. Experimental measurements obtained with a CCD-based speckle contrast detection scheme are in agreement with Monte Carlo simulations and analytical calculations. This study complements previous UOT experiments that demonstrated optical absorption contrast. 相似文献
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Frequency-swept ultrasound-modulated optical tomography in biological tissue by use of parallel detection 总被引:1,自引:0,他引:1
A frequency-swept ultrasonic beam was focused into a biological tissue sample to modulate the laser light passing through the ultrasonic beam inside the tissue. Parallel detection of the speckle field formed by the transmitted laser light was implemented with the source-synchronous-illumination lock-in technique to improve the signal-to-noise ratio. The ultrasound-modulated laser light reflects the local optical and mechanical properties in the ultrasonic beam and can be used for tomographic imaging of the tissue. Sweeping the ultrasonic frequency provides spatial resolution along the ultrasonic axis, which is scalable with the frequency span of the sweep. Two-dimensional images of biological tissue with buried objects were successfully obtained experimentally. 相似文献
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We propose a new detection method for ultrasound-modulated optical tomography that allows us to perform parallel speckle detection with optimum shot-noise sensitivity, using a CCD camera. Moreover, we show that making use of a spatial filter system allows us to fully filter out speckle decorrelation noise. This method is confirmed by a test experiment. 相似文献
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Intense acoustic bursts as a signal-enhancement mechanism in ultrasound-modulated optical tomography
Biophotonic imaging with ultrasound-modulated optical tomography (UOT) promises ultrasonically resolved imaging in biological tissues. A key challenge in this imaging technique is a low signal-to-noise ratio (SNR). We show significant UOT signal enhancement by using intense time-gated acoustic bursts. A CCD camera captured the speckle pattern from a laser-illuminated tissue phantom. Differences in speckle contrast were observed when ultrasonic bursts were applied, compared with when no ultrasound was applied. When CCD triggering was synchronized with burst initiation, acoustic-radiation-force-induced displacements were detected. To avoid mechanical contrast in UOT images, the CCD camera acquisition was delayed several milliseconds until transient effects of acoustic radiation force attenuated to a satisfactory level. The SNR of our system was sufficiently high to provide an image pixel per acoustic burst without signal averaging. Because of the substantially improved SNR, the use of intense acoustic bursts is a promising signal enhancement strategy for UOT. 相似文献
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We propose a new method imaging through scattering media. An object hidden between two biological tissues (chicken breast) is reconstructed from any speckled images obtained from the output of a multichannel optical imaging system. The effect of multiple imaging is achieved with a microlens array. Each lens is the array projects a different speckled image onto a digital camera. The set of speckled images from the entire array is first shifted to a common center and then accumulated into a single average picture. 相似文献
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《中国光学快报(英文版)》2017,(8)
In this Letter, a miniature wearable Raman spectroscopy system is developed. A wearable fiber-optic probe i employed to help the stable and convenient collection of Raman spectra. A nonlinear partial least squares mode based on a multivariate dominant factor is employed to predict the glucose level. The mean coefficients of de termination are 0.99, 0.893, and 0.844 for the glucose solution, laboratory rats, and human volunteers. Th results demonstrate that a miniature wearable Raman spectroscopy system is feasible to achieve the noninvasiv detection of human blood glucose and has important clinical application value in disease diagnosis. 相似文献
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C. A. Millar 《Optical and Quantum Electronics》1981,13(2):125-131
An apparatus which determines optical fibre break angles by a diffraction technique is described. The device measures break angles to an accuracy of 0.15° and is shown to be useful in the evaluation and optimization of breaking machines as well as in the study of properties dependent on the end angle of the fibre in a system. 相似文献
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Chen Z Milner TE Srinivas S Wang X Malekafzali A van Gemert MJ Nelson JS 《Optics letters》1997,22(14):1119-1121
We report the development of an optical technique for noninvasive imaging of in vivo blood flow dynamics and tissue structures with high spatial resolution (2-10 microm) in biological systems. The technique is based on optical Doppler tomography (ODT), which combines Doppler velocimetry with optical coherence tomography to measure blood flow velocity at discrete spatial locations. The exceptionally high resolution of ODT permits noninvasive in vivo imaging of both blood microcirculation and tissue structures surrounding the vessel, which has significance for biomedical research and clinical applications. Tomographic imaging of in vivo blood flow velocity in the chick chorioallantoic membrane and in rodent skin is demonstrated. 相似文献
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Blood flow contrast between tumor and normal tissues in patients with malignant and benign breast cancer was measured by diffuse optical correlation methods. The measurements were carried out with a hand-held optical probe that was manually scanned over the tumor-bearing breast. Increased blood flow was observed in tumor regions relative to healthy tissue, and control subjects did not exhibit significant blood flow heterogeneity. The measurements introduce a new optical contrast for diffuse optical mammography. 相似文献