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1.
Fluorescence diffuse optical tomography (FDOT) is a computationally demanding imaging problem. The discretizations of FDOT forward and inverse problems pose a trade-off between the accuracy and the computational efficiency of the image reconstruction. To address this trade-off, we analyzed the effect of discretization on the accuracy of FDOT imaging and proposed novel adaptive meshing algorithms for FDOT in a series of studies. In this Letter, we apply these new adaptive meshing algorithms to FDOT imaging using real data from a phantom experiment to demonstrate the practical advantages of our algorithms in FDOT image reconstruction. 相似文献
2.
Optical Review - Fluorescent diffuse optical tomography (FDOT) is an emerging imaging modality, with great prospects in areas such as biology and medicine. However, current FDOT encounters... 相似文献
3.
Experimental three-dimensional fluorescence reconstruction of diffuse media by use of a normalized Born approximation 总被引:5,自引:0,他引:5
We present a normalized Born expansion that facilitates fluorescence reconstructions in turbid, tissuelike media. The algorithm can be particularly useful for tissue investigations of fluorochrome distributionin vivo, since it does not require absolute photon-field measurements or measurements before contrast-agent administration. This unique advantage can be achieved only in fluorescence mode. We used this algorithm to three-dimensionally image and quantify an indocyanine fluorochrome phantom, using a novel fluorescence tomographic imager developed for animals. 相似文献
4.
We present a new technique that produces en face tomographic images with a 10-micros acquisition time per image. The setup consists of an interference microscope with stroboscopic illumination provided by a xenon arc flash lamp (10-micros flashes at 15 Hz). The tomographic images are obtained from two phase-opposed interferometric images recorded simultaneously by two synchronized CCD cameras. Transverse resolution better than 1.0 microm is achieved by use of high-numerical-aperture microscope objectives. The short coherence length of the source yields an axial resolution of 0.9 microm. 3 x 3 pixel binning leads to a detection sensitivity of 71 dB. Our system is suitable for various applications, particularly in biology for in vivo cellular-level imaging. 相似文献
5.
Yang VX Mao YX Munce N Standish B Kucharczyk W Marcon NE Wilson BC Vitkin IA 《Optics letters》2005,30(14):1791-1793
Doppler optical coherence tomography (OCT) can image tissue structure and blood flow at micrometer-scale resolution but has limited imaging depth. We report a novel, linear-scanning, needle-based Doppler OCT system using angle-polished gradient-index or ball-lensed fibers. A prototype system with a 19-guage (diameter of approximately 0.9 mm) echogenic needle is constructed and demonstrates in vivo imaging of bidirectional blood flow in rat leg and abdominal cavity. To our knowledge, this is the first demonstration of Doppler OCT through a needle probe in interstitial applications to visualize deeply situated microcirculation. 相似文献
6.
A new three-dimensional (3D) optical fluorescent tomographic imaging scheme is proposed with structured illumination and spatial Fourierdomain decomposition methods for the first time. In this spatial Fourier-decomposition optical fluorescence tomography (SF-OFT), the intensity of focused excitation light from an objective lens is modulated to be a cosine function along the optical axis of the system. For a given position in a two-dimensional (2D) raster scanning process, the spatial frequency of the cosine function along the optical axis sweeps in a proper range while a series of fluorescence intensity are detected accordingly. By making an inverse discrete cosine transformation of these recorded intensity profiles, the distribution of fluorescent markers along the optical axis of a focused laser beam is obtained. A 3D optical fluorescent tomography can be achieved with this proposed SF-OFT technique with a simple 2D raster scanning process. 相似文献
7.
Rocheva V. V. Savelyev A. G. Nechaev A. V. Generalova A. N. Semchishen V. A. Zvyagin A. V. Khaydukov E. V. 《Optics and Spectroscopy》2019,126(1):92-94
Optics and Spectroscopy - We propose a method for obtaining a fluorescence tomographic image for visualization and diagnosis of tissues of a living organism. The method is based on the excitation... 相似文献
8.
A two-dimensional (2D) shape-based approach of image reconstruction using a boundary element method is developed for diffuse optical tomography (DOT). The experimental validation uses a four-channel time- correlated single photon counting (TCSPC) system for detection and an intensity data-type for image reconstruction. The optical and geometric parameters are simultaneously recovered using a difference imaging scheme. Results demonstrate that the proposed DOT modality is a promising methodology of in vivo reconstruction of the optical structures of tissues. 相似文献
9.
Scattering and absorption in the tissues are major problems for in vivo imaging based on a fluorescence reflectance imaging
technique. We evaluated the quantitative relationship between body thickness and fluorescent signals from a deep abdominal
source in intact mice. Mice were injected with quantum dots (peak emission, 800 nm) into the right rear footpad, and fluorescent
signals from the iliac lymph node located deeply in the abdomen were assessed by fluorescence reflectance imaging. Stepwise
compression of the mouse abdomen to reduce the body thickness was attained using a homemade simple device. The iliac node
signals were weak and diffuse without compression but became stronger and more localized with decreasing body thickness. Using
excitation light of approximately 710 nm wavelength, the lymph node/background contrast increased about 16 times with a 4 mm
reduction in body thickness. Contrast enhancement was more evident using shorter wavelength excitation light. Overlying tissues
profoundly affect signals from a deep source in fluorescence reflectance imaging. Our simple compression method may contribute
to quantitatively assessing deep fluorescent sources. 相似文献
10.
Spectroscopic optical coherence tomography 总被引:12,自引:0,他引:12
Morgner U Drexler W Kärtner FX Li XD Pitris C Ippen EP Fujimoto JG 《Optics letters》2000,25(2):111-113
Spectroscopic optical coherence tomography (OCT), an extension of conventional OCT, is demonstrated for performing cross-sectional tomographic and spectroscopic imaging. Information on the spectral content of backscattered light is obtained by detection and processing of the interferometric OCT signal. This method allows the spectrum of backscattered light to be measured over the entire available optical bandwidth simultaneously in a single measurement. Specific spectral features can be extracted by use of digital signal processing without changing the measurement apparatus. An ultrabroadband femtosecond Ti:Al(2)O(3) laser was used to achieve spectroscopic imaging over the wavelength range from 650 to 1000 nm in a simple model as well as in vivo in the Xenopus laevis (African frog) tadpole. Multidimensional spectroscopic data are displayed by use of a novel hue-saturation false-color mapping. 相似文献
11.
Pengfei Sun Biao Deng Guohao Du He Li Weidong Sun Jiangbo Ren Tiqiao Xiao 《X射线光谱测定》2015,44(6):442-446
X‐ray fluorescence computed tomography is an emerging imaging modality that allows for the nondestructive reconstruction of the internal distribution of elements within a sample. The common use of X‐ray excitation energy (up to approximately 20 keV) has necessitated the use of l ‐shell fluorescence for heavy elements. In this study, based on high energy X‐ray at BL13W1 of the Shanghai Synchrotron Radiation Facility, we employed high‐energy excitation for tomographic imaging of the heavy metals (rare earth elements) in fish teeth from deep‐sea sediments on the micrometer scale using K‐shell X‐ray fluorescence. The virtual cross‐sectional distribution of La, Ce, Pm, Pr, Nd, and Sm were obtained, thereby providing a feasible approach for analyzing the enrichment mechanism of rare earth elements. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
12.
The study of flow dynamics in complex geometry vessels is highly important in various biomedical applications where the knowledge
of the mechanic interactions between the moving fluid and the housing media plays a key role for the determination of the
parameters of interest, including the effect of blood flow on the possible rupture of atherosclerotic plaques. Doppler Optical
Coherence Tomography (DOCT), as a functional extension of Optical Coherence Tomography (OCT), is an optic, non-contact, noninvasive
technique able to achieve detailed analysis of the flow/vessel interactions. It allows simultaneous high resolution imaging
(∼10 μm typical) of the morphology and composition of the vessel and determination of the flow velocity distribution along
the measured cross-section. We applied DOCT system to image high-resolution one-dimensional and multi-dimensional velocity
distribution profiles of Newtonian and non-Newtonian fluids flowing in vessels with complex geometry, including Y-shaped and
T-shaped vessels, vessels with aneurism, bifurcated vessels with deployed stent and scaffolds. The phantoms were built to
mimic typical shapes of human blood vessels, enabling preliminary analysis of the interaction between flow dynamics and the
(complex) geometry of the vessels and also to map the related velocity profiles at several inlet volume flow rates. Feasibility
studies for quantitative observation of the turbulence of flows arising within the complex geometry vessels are discussed.
In addition, DOCT technique was also applied for monitoring cerebral mouse blood flow in vivo. Two-dimensional DOCT images
of complex flow velocity profiles in blood vessel phantoms and in vivo sub-cranial mouse blood flow velocities distributions
are presented. 相似文献
13.
14.
The intrinsic aberrations of high-NA gradient refractive index (GRIN) lenses limit their image quality as well as field of view. Here we used a pupil-segmentation-based adaptive optical approach to correct the inherent aberrations in a two-photon fluorescence endoscope utilizing a 0.8 NA GRIN lens. By correcting the field-dependent aberrations, we recovered diffraction-limited performance across a large imaging field. The consequent improvements in imaging signal and resolution allowed us to detect fine structures that were otherwise invisible inside mouse brain slices. 相似文献
15.
多功能无线光电鼠标运用2个图像摄影芯片,通过轨迹球滚动和鼠标座身移动两种方式实现光标移动。通过比较原始鼠标光路中2个图像摄影芯片能够接收到的最小光通量百分比,选择ADNS7530作为鼠标中唯一保留的图像摄影芯片。保持轨迹球光路不变,鼠标座光路中增加一个与轨迹球光路相同的LED光源。比较鼠标座的桌面反射光分别通过轨迹球反射、棱镜反射和平面镜反射后,最终到达图像摄影芯片的光通量百分比。确定并验证了鼠标座光路采用平面反射镜的设计方案,实现了无线空中操作鼠标轨迹球光路和鼠标座光路共用1个图像摄影芯片的目的。 相似文献
16.
We demonstrate high-speed complex conjugate artifact (CCA) resolved imaging of human retina in vivo using spectral domain optical coherence tomography. This technique utilizes sinusoidal reference mirror modulation to implement high-speed integrating buckets acquisition and a quadrature projection reconstruction algorithm in postprocessing. This method is illustrated experimentally using sets of four integrating bucket phase scans, acquired at 52 kHz, for DC suppression of 73 dB and complex conjugate suppression of 35 dB. Densely sampled (3000 A-scans/image, acquired at 4.3 images/s) full-depth in vivo images of optic nerve head show CCA suppression for most image reflections to the noise floor. 相似文献
17.
Our preliminary results on two-dimensional (2D) optical tomographic imaging of hemodynamic changes in a preterm infant brain are reported. We use the established 16-channel time-correlated single photon counting system for the detection and generalized pulse spectrum technique based algorithm for the image reconstruction. The experiments demonstrate that diffuse optical tomography may be a potent means for investigating brain functions and neural development of infant brains in the perinatal period. 相似文献
18.
We present three-dimensional tomographic images of the absorption coefficient that is due to the presence of a fluorophore reconstructed from frequency domain fluence measurements of a tissue phantom containing a single, fluorescence contrast-enhanced inclusion. We show that such a reconstruction may be improved when the importance of measurement error correlations between relative phase shift and amplitude is assessed and when measurements are preprocessed to reduce the magnitude and the bias of system error. 相似文献
19.
This paper describes a new application of optical heterodyne detection using a laser beam for two-dimensional imaging of the internal structure of strongly scattering media in which the structure is completely obstructed from normal visual observation. The directional resolution capability for image formation due to the excellent antenna properties of the heterodyne technique is verified experimentally using a ground glass to cause strong scattering of the signal beam. Successful image detection of a test target placed in a highly scattering absorptive medium, with spatial resolution better than 400 m in the case of our experiments, demonstrates that this Coherent Detection Imaging (CDI) method can overcome the diffuse nature of images in media such as those of biomedical interest and others to achieve scanning and tomographic imaging. 相似文献
20.
This Letter presents a useful method that combines the full range complex Fourier domain optical coherence tomography (OCT) with the ultrahigh sensitive optical microangiography (OMAG) to achieve full range complex imaging of blood flow within microcirculatory tissue beds in vivo. We propose to use the fast scanning axis to realize the full range complex imaging, while using the slow axis to achieve OMAG imaging of blood flow. We demonstrate the proposed method by using a high speed 1310?nm OCT/OMAG system running at 92?kHz line scan rate to image the flow phantoms in vitro, and the blood flows in tissue beds in vivo. 相似文献