نتایج جستجو برای: variable resolution x ray vrx ct

تعداد نتایج: 1231260  

A.R. Kamali Asl, H. Arabi, S.M. Aghamiri,

Background: A variable resolution X-ray (VRX) CT scanner provides a great increase in the spatial resolution. In VRX CT scanners, the spatial resolution of the system and its field of view (FOV) can be changed according to the object size. One of the main factors that limit the spatial resolution of VRX CT scanner is the effect of the X-ray focal spot. Materials and Methods: A theoreti...

Journal: :Medical physics 2011
Hosein Arabi Ali Reza Kamali Asl Mohammad Reza Ay Habib Zaidi

PURPOSE The variable resolution x-ray (VRX) CT scanner provides substantial improvement in the spatial resolution by matching the scanner's field of view (FOV) to the size of the object being imaged. Intercell x-ray cross-talk is one of the most important factors limiting the spatial resolution of the VRX detector. In this work, a new cell arrangement in the VRX detector is suggested to decreas...

Journal: :iranian journal of medical physics 0
hossein arabi m.sc. student, radiation medicine dept., shahid beheshti university, tehran, iran. alireza kamali asl assistant professor, nuclear engineering dept., shahid beheshti university, tehran, iran. seyed mahmood reza aghamiri associate professor, nuclear engineering dept., shahid beheshti university, tehran, iran.

introduction: variable resolution x-ray (vrx) ct is a new type of ct that can image objects at various spatial resolutions. in a vrx ct scanner, the spatial resolution increases at the cost of reduction in the field of view (fov). an important factor that limits the spatial resolution of the vrx ct is the effect of focal spot size. also, the optimum magnification is different at each incident a...

Journal: :iranian journal of radiation research 0
h. arabi radiation medicine department, shahid beheshti university, tehran, iran a.r. kamali asl radiation medicine department, shahid beheshti university, tehran, iran s.m. aghamiri radiation medicine department, shahid beheshti university, tehran, iran

background: a variable resolution x-ray (vrx) ct scanner provides a great increase in the spatial resolution. in vrx ct scanners, the spatial resolution of the system and its field of view (fov) can be changed according to the object size. one of the main factors that limit the spatial resolution of vrx ct scanner is the effect of the x-ray focal spot. materials and methods: a theoretical study...

Alireza Kamali Asl, Hossein Arabi Seyed Mahmood Reza Aghamiri

Introduction: Variable resolution x-ray (VRX) CT is a new type of CT that can image objects at various spatial resolutions. In a VRX CT scanner, the spatial resolution increases at the cost of reduction in the field of view (FOV). An important factor that limits the spatial resolution of the VRX CT is the effect of focal spot size. Also, the optimum magnification is different at each incident a...

2010
H. Arabi A. R. Kamali Asl S. M. Aghamiri Ali Reza Kamali

*Corresponding author: Dr. Ali Reza Kamali Asl, Radiation Medicine Department, Shahid Beheshti University, Tehran, Iran. Fax: +98 21 22431780 E-mail: [email protected] Background: A variable resolution X-ray (VRX) CT scanner provides a great increase in the spatial resolution. In VRX CT scanners, the spatial resolution of the system and its field of view (FOV) can be changed according to the...

2012
H. Arabi A. R. Kamali

The purpose of this work is measurement of the system presampling MTF of a variable resolution x-ray (VRX) CT scanner. In this paper, we used the parameters of an actual VRX CT scanner for simulation and study of effect of different focal spot sizes on system presampling MTF by Monte Carlo method (GATE simulation software). Focal spot size of 0.6 mm limited the spatial resolution of the system ...

Journal: :Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics 2015
Hossein Arabi Ali Reza Kamali Asl Mohammad Reza Ay Habib Zaidi

OBJECTIVE The purpose of this work is to evaluate the impact of optimization of magnification on performance parameters of the variable resolution X-ray (VRX) CT scanner. METHODS A realistic model based on an actual VRX CT scanner was implemented in the GATE Monte Carlo simulation platform. To evaluate the influence of system magnification, spatial resolution, field-of-view (FOV) and scatter-...

Journal: :Biological research 2005
Mauricio Canals Ricardo Olivares Mario Rosenmann

In this paper we develop a method to estimate lung volume using chest x-rays of small mammals. We applied this method to assess the lung volume of several rodents. We showed that a good estimator of the lung volume is: V*L = 0.496 x VRX approximately equal to 1/2 x VRX, where VRX is a measurement obtained from the x-ray that represents the volume of a rectangular box containing the lungs and me...

Introduction: Crosstalk is a leakage of X-ray or light produced in a matrix of X-ray detectors or array of photodiodes in one element to other elements affecting on image contrast and spatial resolution. In this study, we assessed X-ray crosstalk in a computed tomography (CT) scanner with small detector elements to estimate the effect of various parameters such as X-ray tube voltage, detector e...

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