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Early detection and diagnosis of skin cancer is essential to treating the malignancy and preventing death. Subsurface features and depth information are critical in evaluating a skin lesion for this early malignancy screening. We present a novel voxel-based Monte Carlo simulation of light propagation in skin tissue which runs in a highly parallel environment on desktop graphics processors, resulting...
We present a system to keep track of a destructive process such as a medical specimen dissection, from data acquisition to interactive and immersive visualization, in order to build ground truth models. Acquisition is a two-step process, first involving a 3D laser scanner to get a 3D surface, and then a high resolution camera for capturing the texture. This acquisition process is repeated at each...
Electroencephalography (EEG) and magneto-encephalography (MEG) are both currently used to reconstruct brain activity. The performance of inverse source reconstructions is dependent on the modality of signals in use as well as inverse techniques. Here we used a recently proposed sparse source imaging technique, i.e., the variation-based sparse cortical current density (VB-SCCD) algorithm to compare...
Magnetic Resonance Electrical Impedance Tomography (MREIT) produces cross-sectional images of a conductivity distribution inside the human body. We use an MRI scanner as a tool to measure induced internal magnetic flux density distributions subject to externally injected currents. Recent experimental MREIT studies demonstrated conductivity image reconstructions of in vivo animal and human subjects...
In this study, an electromagnetics-based inverse sensitivity mapping method is introduced for applications in high field MRI. Instead of using simplistic numerical approximations, the sensitivity of the radio-frequency coil was determined through a field approach by using iterative optimization. The current study is an extension to previous studies on the inverse method, which has restricted itself...
Algebraic Reconstruction Technique (ART) is a widely employed method in computed tomography since it has certain advantages, such as allowing reconstruction of data with missing projections in some angle ranges, over other techniques such as Filtered Back Projection (FBP). Recently, a regularisation technique for ART, RegART, was introduced which provides greatly reduced noise levels. However, a serious...
Microwave Tomography (MT) can determine the permittivity and conductivity of a volume of interest; it has been shown that a contrast exists between these electrical properties in healthy and malignant tissues, and MT can be used to discern the dielectric contrast image of these tissues by recovering their electrical property values. Simulation and phantom experiments of objects with known spatial...
ISAF (icosahedral symmetry-adapted functions) algorithm is the new high-resolution algorithm of icosahedral molecules. But its running speed is very slow because of the time-consuming operations of mapping sampling points into 3D space. In this paper, a fast mapping method is proposed to increase the running speed of this stage. First of all, the angle corresponding to one pixel arc in the maximum...
We have constructed a thermal stereoscope utilizing three digital SLR cameras and an infrared camera for rapid surface reconstruction of diabetic foot geometry and temperature distribution. A structured light pattern is projected on to the foot to provide approximately 2500 reconstructed points. The reconstructed point cloud is then fitted to a finite element model, producing root mean squared errors...
One of the main sources of signal degradation in rapid MR acquisitions, such as Echo Planar Imaging (EPI), is magnetic field variations caused by field inhomogeneities and susceptibility gradients. If unaccounted for during the reconstruction process, this spatially-varying field can cause severe image artifacts. In this paper, we show that correcting for the resulting degradations can be formulated...
Compressed Sensing (CS) takes advantage of the sparsity of MR images in certain bases or dictionaries to obtain accurate reconstructions from undersampled k-space data. The (pseudo) random sampling schemes used most often for CS may have good theoretical asymptotic properties; however, with limited data they may be far from optimal. In this paper, we propose a novel framework for improved adaptive...
Fast MRI makes it possible to visualize dynamic biological phenomena and can potentially reduce the cost of diagnostic imaging. Constrained imaging methods such as compressive sense (CS) and optimal lattice sampling (OLS) have proven to be effective for speeding up MRI. In doing so, CS takes advantage of the image sparsity or compressibility and OLS utilizes the known signal/spectrum support. Interestingly,...
A robust lesion segmentation method is critical for quantification of lesion activity in positron emission tomography (PET), especially for the cases where lesion boundary is not discernible in the corresponding computed tomography (CT). However, lesion delineation in PET is a challenging task, especially for small lesions, due to the low intrinsic resolution, image noise and partial volume effect...
Epilepsy patients with Landau-Kleffner syndrome (LKS) usually have a normal brain structure, which makes it a challenge to identify the epileptogenic zone only based on magnetic resonance imaging (MRI) data. A sparse source imaging technique called variation based sparse cortical current density (VB-SCCD) imaging was adopted here to reconstruct cortical sources of magnetoencephalography (MEG) interictal...
Head motion during brain CT studies can degrade the reconstructed image by introducing distortion and loss of resolution, thereby contributing to misdiagnosis of diseases. In this paper, we have proposed a correlation coefficient and Least Squares Support Vector Machines (LS-SVM) based approach to detect and mitigate motion artifacts in FDK based three-dimensional cone-beam tomography. Motion is detected...
The objective of this study is to develop an innovative close range digital photogrammetry (CRDP) system using the commercial digital SLR cameras to measure and reconstruct the 3D surface of prosthetics and orthotics. This paper describes the instrumentation, techniques and preliminary results of the proposed system. The technique works by taking pictures of the object from multiple view angles. The...
Registration of histology to three-dimensional (3D) magnetic resonance (MR) images is often required for the analysis of brain structure and investigation of brain pathologies. A novel algorithm for deformable registration of an individual histological section to a brain MR image is described. The cost function uses a novel hybrid intensity- and boundary surface-based measure that reflects the contrast...
In this paper, we formulate the parallel magnetic resonance imaging(pMRI) as a multichannel blind deconvolution problem with subsampling. First, the model allows formal characterization of image solutions consistent with data obtained by uniform subsampling of k-space. Second, the model allows analysis of the minimum set of required calibration data. Third, the filter bank formulation provides analysis...
Digital breast tomosynthesis (DBT) is a limited-angle tomographic x-ray imaging technique that reduces the effect of tissue superposition observed in planar mammography. An integrated imaging platform that combines DBT with near infrared spectroscopy (NIRS) to provide co-registered anatomical and functional imaging is under development. Incorporation of anatomic priors can benefit NIRS reconstruction...
Transcranial sonography has been an increasingly widespread diagnostic tool for the diagnosis of neural diseases like Parkinson's disease. However, the utilization of modern 3D ultrasound techniques has been hampered by the acoustical barrier of the skull bones. We report the development of and preliminary results from an ultrasound helmet which uses mechanical beam-steering to allow 3-D reconstruction...
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