نتایج جستجو برای: spect slit slat collimator
تعداد نتایج: 23367 فیلتر نتایج به سال:
Background: Photon attenuation as an inevitable physical phenomenon influences on the diagnostic information of SPECT images and results to errors in accuracy of quantitative measurements. This can be corrected via different physical or mathematical approaches. As the correction equation in mathematical approaches is nonlinear, in this study a new method of linearization called ‘Piece Wise Line...
MEDISIP, Department of Electronics and Information Systems, Ghent University-iMinds Medical ITIBiTech, Ghent, Belgium Digital photon counters (DPC, Philips Digital Photon Counting) are compact photon detectors that are promising for the design of a compact SPECT insert for MRI. Given the small bore of most preclinical MR scanners such an insert has to fulfil strict space constraints. In DPCs th...
For transmission computed tomography (TCT) systems using a centered transmission source with a fan-beam collimator, the transmission projection data are truncated. To achieve sufficiently large imaging field of view (FOV), we have designed the combination of an asymmetric fan-beam (AsF) collimator and a small uncollimated sheet-source for TCT, and implemented AsF sampling on a two-head SPECT sy...
In order to model photon attenuation and detector resolution variation as a depth-dependent convolution for efficient reconstruction of quantitative SPECT, a central-ray approximation is necessary. This work investigates the impact of the approximation upon reconstruction accuracy and computational efficiency. A patient chest CT image was acquired and converted into an object-specific attenuati...
Single photon emission computed tomography (SPECT) is based on the measurement of radiation emitted by a radiotracer injected into the patient. Because of photoelectric absorption and Compton scatter, the gamma photons are attenuated inside the body before arriving at the detector. A quantitative reconstruction must consider the attenuation, which is usually nonuniform. Novikov has derived an e...
Proton range monitoring may facilitate online adaptive proton therapy and improve treatment outcomes. Imaging of proton-induced prompt gamma (PG) rays using a knife-edge slit collimator is currently under investigation as a potential tool for real-time proton range monitoring. A major challenge in collimated PG imaging is the suppression of neutron-induced background counts. In this work, we pr...
OBJECTIVE Almost all small animal SPECT is performed with pinhole collimators (PH), including single-PH (SPH) and multi-PH (MPH). In the clinical study, not only PH but also parallel-hole collimator (PAH) is often used in planar and SPECT imaging. However, there have been no comparative studies on image quality with various collimators on the small animal imaging. This study compared the basic ...
To examine the impact of acquisition time on Lutetium-177 (177Lu) single-photon emission computed tomography (SPECT) images using Monte Carlo simulation. A gamma camera simulation based method was performed to produce SPECT images. The phantom modeled a NEMA IEC BODY including six spheres as tumors. After administration 7.4 GBq 177Lu, radioactivity concentrations tumor/liver at 6, 24, and 72 h ...
3D iterative reconstruction of Single Photon Emission Computed Tomography (SPECT) acquisitions is a widely used but computationaly intensive process. Reconstructing data from a rotating slat collimated system increases the computation time even further. Since the sensitivity profile of such a camera is not constant over the field of view, it is important to include a system model that is as acc...
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