نتایج جستجو برای: spect slit slat collimator

تعداد نتایج: 23367  

2010
A. Vahidian Kamyad M. H. Noori Eskandari M. Naji Midani M. Hajizadeh Saffar

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...

2014
Carmen Bouckaert Stefaan Vandenberghe Roel Van Holen

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...

Journal: :Annals of nuclear medicine 2004
Akihiro Kojima Seiji Tomiguchi Koichi Kawanaka Daisuke Utsunomiya Shinya Shiraishi Takeshi Nakaura Noboru Katsuda Masanori Matsumoto Yasuyuki Yamashita Nobutoku Motomura Takashi Ichihara

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...

Journal: :Physics in medicine and biology 1997
Z Liang J Cheng J Ye

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...

2001
Junhai Wen Tianfang Li Zhengrong Liang

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...

Journal: :Physics in medicine and biology 2015
Patricia Cambraia Lopes Enrico Clementel Paulo Crespo Sebastien Henrotin Jan Huizenga Guillaume Janssens Katia Parodi Damien Prieels Frauke Roellinghoff Julien Smeets Frederic Stichelbaut Dennis R Schaart

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...

Journal: :Annals of nuclear medicine 2013
Yusuke Higaki Masato Kobayashi Tomoya Uehara Hirofumi Hanaoka Yasushi Arano Keiichi Kawai

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 ...

Journal: :Annals of Nuclear Medicine 2021

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 ...

2006
Jan De Beenhouwer Roel Van Holen Stefaan Vandenberghe Steven Staelens Yves D'Asseler Ignace Lemahieu

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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