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Imaging phantom

About: Imaging phantom is a research topic. Over the lifetime, 28170 publications have been published within this topic receiving 510003 citations. The topic is also known as: phantom.


Papers
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Journal ArticleDOI
15 Oct 2000
TL;DR: In this paper, a method for direct calibration of an optical motion-tracking system to the reconstruction coordinate frame using paired coordinate measurements obtained simultaneously from a PET scanner and tracking system is presented.
Abstract: Methods capable of correcting for head motion in all six degrees of freedom have been proposed for positron emission tomography (PET) brain imaging but not yet demonstrated in human studies. These methods rely on the accurate measurement of head motion in relation to the reconstruction coordinate frame. We present methodology for the direct calibration of an optical motion-tracking system to the reconstruction coordinate frame using paired coordinate measurements obtained simultaneously from a PET scanner and tracking system. We also describe the implementation of motion correction, based on the multiple acquisition frame method originally described by Picard and Thompson (1997), using data provided by the motion tracking system. Effective compensation for multiple six-degree-of-freedom movements is demonstrated in dynamic PET scans of the Hoffman brain phantom and a normal volunteer. We conclude that reduced distortion and improved quantitative accuracy can be achieved with this method in PET brain studies degraded by head movements.

191 citations

Journal ArticleDOI
TL;DR: This paper introduces two real-time elastography techniques based on analytic minimization (AM) of regularized cost functions that produce axial strain and integer lateral displacement, while the second method produces both axial and lateral strains.
Abstract: This paper introduces two real-time elastography techniques based on analytic minimization (AM) of regularized cost functions. The first method (1D AM) produces axial strain and integer lateral displacement, while the second method (2D AM) produces both axial and lateral strains. The cost functions incorporate similarity of radio-frequency (RF) data intensity and displacement continuity, making both AM methods robust to small decorrelations present throughout the image. We also exploit techniques from robust statistics to make the methods resistant to large local decorrelations. We further introduce Kalman filtering for calculating the strain field from the displacement field given by the AM methods. Simulation and phantom experiments show that both methods generate strain images with high SNR, CNR and resolution. Both methods work for strains as high as 10% and run in real-time. We also present in vivo patient trials of ablation monitoring. An implementation of the 2D AM method as well as phantom and clinical RF-data can be downloaded.

191 citations

Journal ArticleDOI
TL;DR: Estimation of patient dose and personnel exposure from phantom measurements during computed tomographic (CT) fluoroscopy is used to provide users with dose information, and to recommend methods to reduce exposure.
Abstract: PURPOSE: To estimate patient dose and personnel exposure from phantom measurements during computed tomographic (CT) fluoroscopy, to use the estimates to provide users with dose information, and to recommend methods to reduce exposure. MATERIALS AND METHODS: Surface dose was estimated on a CT dosimetric phantom by using thermoluminescent dosimetric (TLD) and CT pencil chamber measurements. Scatter exposure was estimated from scattered radiation measured at distances of 10 cm to 1 m from the phantom. Scatter exposures measured with and without placement of a lead drape on the phantom surface adjacent to the scanning plane were compared. RESULTS: Phantom surface dose rates ranged from 2.3 to 10.4 mGy/sec. Scattered exposure rates for a commonly used CT fluoroscopic technique (120 kVp, 50 mA, 10-mm section thickness) were 27 and 1.2 μGy/sec at 10 cm and 1 m, respectively, from the phantom. Lead drapes reduced the scattered exposure by approximately 71% and 14% at distances of 10 and 60 cm from the scanning pl...

191 citations

Journal ArticleDOI
TL;DR: This study shows that the newly developed cone beam CT system produces high resolution three-dimensional volumetric images that will be useful for the examination of dentomaxillofacial disorders.
Abstract: Objective: The purpose of this paper is to present the system configuration and physical properties of a new dentomaxillofacial X-ray cone beam CT system (CB MercuRay™) being developed. Methods: The system consists of an image intensifier and a cone beam X-ray source. There are two different models of this system, each with a different size image intensifier, 9″ or 12″. Each system has three field of view (FOV) modes. The 12″ system has facial (F), panoramic (P) and implant (I) FOV modes. The 9″ system has P, I and dental (D) modes. Images produced by these systems consist of 512×512×512 isotropic voxels. Physical properties such as resolution, noise and distortion of the images were evaluated in this study. Modulation transfer function (MTF) was measured using Boone's method. Image noise was measured as the standard deviation of the CT value in water. Circularity of the axial images yielded by the two models was measured using an 8 mm diameter acrylic pipe phantom. Results: The resolving power at a MTF o...

191 citations

Journal ArticleDOI
TL;DR: A novel speed function for surface evolution that is derived from either diffusion tensor data, high angular resolution diffusion data, or a combined DT-HARD hybrid approach is introduced, which uses the model-free q-ball imaging approach for HARD reconstruction.

190 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,623
20223,476
20211,221
20201,482
20191,568
20181,503