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...

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...

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...

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...

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...

*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...

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 ...

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-...

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...