Introduction: One of the main steps in the optimization process in diagnostic imaging is the quality control of radiology devices. The usual method of CT scan calibration is used of a phantom. The phantom created a certain weakening for the radiation through which it passes. One of the most suitable methods for quantitative analysis of the resolution and contrast in CT scan im...

PURPOSE To develop an easily-implemented technique with free publicly-available analysis software to measure the modulation transfer function (MTF) and noise-power spectrum (NPS) of a clinical computed tomography (CT) system from images acquired using a widely-available and standardized American College of Radiology (ACR) CT accreditation phantom. METHODS Images of the ACR phantom were acquir...

The modulation transfer function (MTF) is the technical description of spatial resolution for most imaging systems. the MTF describes how well an imaging system processes signal [1,4]. There are several methods for calculation of MTF that can be categorized in theoretical and experimental methods. In this study, in order to compare the performance of five different commercial CT scanner, an exp...

Accurate measurement of spatial resolution in terms modulation transfer function (MTF) is essential computed tomography (CT) images. The purpose this study was to developed a computational phantom that can be used evaluate the effect noise on MTF CT Our phantoms for measuring were with MATLAB software. image blurred by point spread certain standard deviation. Subsequently, different levels adde...

OBJECTIVE: The purpose of the current study was to evaluate the effect of an iterative reconstruction algorithm named advanced modeled iterative reconstruction (ADMIRE) on improving image quality and reducing the radiation dose. MATERIALS AND METHODS: The Catphan phantom (Phantom Lab, USA) was scanned on a SOMATOM Force CT scanner (Siemens Healthcare, Forchheim, Germany) with different exposure...

The image quality (IQ) of imaging systems must be sufficiently high for image-guided radiation therapy (IGRT). Hence, users should implement a quality assurance program to maintain IQ. In our routine IQ tests of the kV cone-beam CT system (Elekta XVI), image noise was quantified by noise standard deviation (NSD), which was the standard deviation of CT numbers measured in a small area in an imag...

Purpose: To experimentally validate the Fastcat cone beam CT (CBCT) simulator against kV and MV CBCT images acquired with a Varian Truebeam linac. Methods: of Catphan 504 phantom were using 100 kVp on-board imager (OBI) 6 treatment electronic portal imaging device (EPID), respectively. The simulation was performed detailed models x-ray source, bowtie filter, high resolution voxelized virtual ph...

Introduction: Total Skin Electron Therapy (TSET) and Total Body Irradiation (TBI) are kinds of treatment which use electron and photon beams to treat special types of cancers. The aim of these techniques are to deliver uniform dose to the entire skin while minimizing delivered dose to organs at risk. To check the homogeneity of dose delivery in TBI and TSET, using a humanoid ph...

PURPOSE Iterative reconstruction (IR) technique is growingly used in clinical CT imaging due to its ability to provide improved image quality at lower patient doses. However, the nonlinear frequency response of IR technique, which may affect quantitative analysis, is rarely explored. This study evaluates noise level and contrast dependent behavior of MTF in IR CT imaging with a multi-contrast s...

The grating-based x-ray differential phase contrast (DPC) CT is emerging as a new technology with the potential for extensive preclinical and clinical applications. In general, the performance of an imaging system is jointly determined by its signal property (modulation transfer function–MTF(k)) and noise property (noise power spectrum–NPS(k)), which is characterized by its spectrum of noise eq...