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In the present paper, we propose a new magnetic resonance fast scan technique using the phase-scrambling Fourier transform imaging (PSFT), in which the strategy of data acquisition is similar to that of the standard Fourier imaging technique. The Fourier transformed image in the PSFT has a phase modulation in which the local spatial frequency is increased as the position moves away from the center...
The proper segmentation of the vascular system of the retina has a very important role in automatic screening systems. Its detection helps the localization of other anatomical parts and also the detection of possible vascular disorders. State-of-the-art machine learning algorithms are reported to have good performance in this field. However, with the spatial resolution of the fundus images growing,...
Fourier Transform Infrared (FT-IR) spectroscopic imaging is a potentially valuable tool for diagnosing breast and prostate cancer, but its clinical deployment is limited due to long data acquisition times and vast storage requirements. To counter this limitation, we develop a sparse representation for FT-IR absorbance spectra using a learned dictionary. This sparse representation is used as prior...
Single pinhole SPECT can provide high-resolution functional imaging of small animals, while multipinhole SPECT can further increase photon sampling and hence improve system sensitivity. In addition, overlapping projection of a multipinhole system can improve the overall usage of detector area, but such a multiplexing detection inevitably leads to image quality deterioration. Since iterative image...
A staggered detector geometry is proposed for pinhole camera SPECT imaging of breast cancer. Several such systems are simulated in two dimensions, with reconstructed images evaluated for spatial resolution, noise, and artifacts. Designs for dedicated breast SPECT scanners generally involve moving a detector around the breast. Multiple detectors have greater detection efficiency. With enough detectors,...
We propose a method for multiresolution image reconstruction in X-ray micro computed tomography (microCT). It can have a variety of applications, from material characterization to small animal imaging studies. The main idea is to recover an overall image of the sample with a coarse resolution, and with a fine resolution for a region-of-interest (ROI). In a zoo-min CT type setup, two sets of data are...
The objective of this research is to demonstrate a modified statistical system model and an approach of accelerated Monte Carlo simulation for studying the capability of a dual-planar Compton medical imaging system constructed with silicon and NaI detectors to image 364.4 keV energy photons emitted from I131. The Compton imaging system is a potential medical imaging instrument for effectively observing...
A full ring small animal PET camera (MiniPET-II) has been built in our institute as part of an R+D project. In this work we determined the performance parameters of the MiniPET-II scanner. The measurements and data evaluation for this purpose were based on the National Electrical Manufacturers Association (NEMA) NU-4 standards. The spatial resolution varies between 1.4 to 2.1 mm from central to 25...
In this paper, we present a technique to modify the power of the backprojection weight in analytic CT reconstruction formulas. The technique is applicable whenever the processing step that precedes the backprojection can be formulated as a data differentiation. To illustrate its merit, we apply our technique to the classical, ramp-filter based, short-scan fan-beam reconstruction formula to obtain...
SiliSPECT, a multi-pinhole, multi-detector SPECT system, was designed to image targeted-regions of rodents at sub-300 ??m resolution with motionless data acquisition and a special reconstruction method. High spatial resolution is achieved with thick silicon double-sided strip detectors (DSSDs) and 250 ??m pinhole apertures. Each of the two heads contains two stacked DSSDs, which improves total detection...
This work proposes a new restoration method to improve mammographic images by using Anscombe transform and Wiener filter to quantum noise reduction. Besides, it is performed an image enhancement by using a restoration inverse filter, calculated based on the image system modulation transfer function (MTF). This pre-processing technique were used for a set of mammographic phantom images in order measure...
Cone-beam CT system has become a hot issue in current CT technique. Compared with the traditional 2D CT, cone beam CT can greatly reduce the scanning time, improve the utilization ratio of X-ray, and enhance the spatial resolution. In the article, simulation data based on the 3D Shepp-Logan Model was obtained by tracing the X-ray and applying the radial attenuation theory. FDK (Feldkamp, Davis and...
Single photon emission CT (SPECT) systems with a semiconductor detector have several advantages compared with conventional SPECT systems with a NaI(Tl) scintillation detector in terms of energy resolution and spatial resolution. On the other hand, one of the disadvantages of the detector is a small field-of-view (FOV), and thus we proposed a new SPECT system with a diverging collimator to enlarge...
In this study we investigate the feasibility of performing small animal SPECT imaging on a clinical SPECT scanner with a dedicate pinhole collimator. Analytical formulae are used to calculate spatial resolution and absolute sensitivity given a pinhole collimator design scheme. Two optimal pinhole designs are proposed in terms of achieving the best trade-off between spatial resolution and absolute...
We developed SPECT imaging capability on an animal PET scanner by placing a slit-slat collimator inside the PET detector gantry. To perform in vivo animal imaging with minimal gravity induced animal motion, we investigated the performance of hybrid rotation-translation (HRT) tomographic scan scheme in this paper. Three evaluation indices, i.e. sampling completeness (SC), sensitivity, and directional...
The aim of this study is to develop a MR compatible PET that is insertable to MRI and allows simultaneous PET and MR imaging of human brain. The brain PET having 72 detector modules arranged in a ring of 330 mm diameter was designed. Each PET module composed of 4 ? 4 matrix of 3 mm ? 3 mm ? 20 mm LYSO crystals coupled to a tileable 4 ? 4 array Geigermode avalanche photodiode (GAPD) and designed to...
Partial volume effects (PVEs) are well-known consequences of the limited spatial resolution in emission tomography which can affect the quality of PET oncology images both qualitatively and quantitatively and thus impact the diagnostic task. There exists a wide variety of PVE correction methods but they are not all well suited to oncology images. In an attempt to obviate the need for drawing or segmenting...
The LOR rebinning technique for motion correction in PET imaging has been shown to compensate effectively for rigid motion. Each individual event, represented as an LOR, is spatially transformed to compensate for motion of the object during the scan. The main limitation of this technique is that some motion-corrected events which fall out of the acceptance range of the 3D sinogram are discarded, reducing...
We have developed a compact and modular gamma camera system and assessed its performance when used on a small-animal SPECT prototype (rSPECT). Each camera consists of a Hamamatsu H-8500 position sensitive photomultiplier tube coupled to a 30 ?? 30 NaI (Tl) scintillator array (1.4mm ?? 1.4mm ?? 6mm crystal size) and electronics for pre-processing and matching the detector signals to an in-house developed...
For diagnosis of very small lesions of breast cancer on very early stage, a dedicated breast positron emission tomography (PET) scanner consisting of four-layer depth of interaction (DOI) detectors is now under development. We are aiming for the spatial resolution of less than 1 mm across a large effective field of view (FOV), and acquisition time of less than 5 minutes for each breast and 10 minutes...
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