نتایج جستجو برای: phantom ct mtf phantom autocad modulation

تعداد نتایج: 300098  

Journal: :iranian journal of radiation research 0
f. babapour mofrad faculty of engineering, science and research branch, islamic azad university, tehran, iran r. aghaeizadeh zoroofi control and intelligent processing center of excellence, school of electrical and computer engineering, college of engineering, university of tehran, tehran, iran a. abbaspour tehrani fard electrical and electronic engineering school, sharif university of technology, tehran, iran sh. akhlaghpoor department of interventional radiology, sina hospital, tehran university of medical sciences, tehran, iran y.w. chen college of information and science, ristumeikan university, shiga, japan y. sato division of image analysis, graduate school of medicine, osaka university, osaka, japan

background: in nuclear medicine application often it is required to use computational methods for evaluation of organ absorbed dose. monte carlo simulation and phantoms have been used in many works before. the shape, size and volume in organs are varied, and this variation will produce error in dose calculation if no correction is applied. materials and methods: a computational framework for co...

2013
Jing Zou Xiao-Dong Hu Hanyu Lv Xiaotang Hu

The effects of calibration phantoms on the correction results of the empirical artifacts correction method (ECCU) for the case of tube modulation were investigated. To improve the validity of the ECCU method, the effect of the geometry parameter of a typical single-material calibration phantom (water calibration phantom) on the ECCU algorithm was investigated. Dual-material calibration phantoms...

2010
Thomas Boltz William Pavlicek Robert Paden Markus Renno Angela Jensen Metin Akay

The current work describes an anthropomorphic beating heart phantom constructed as a tool for the assessment of technological advances in cardiac x-ray computed tomography (CT). The phantom is comprised of a thorax, a compressor system, an ECG system, a beating heart with tortuous coronary arteries, and the option to add or remove pathologies such as aberrant beats, stents, and plaques. Initial...

Journal: :Physics in medicine and biology 2008
Kathy Willowson Dale L Bailey Clive Baldock

A method for achieving quantitative single-photon emission computed tomography (SPECT) based upon corrections derived from x-ray computed tomography (CT) data is presented. A CT-derived attenuation map is used to perform transmission-dependent scatter correction (TDSC) in conjunction with non-uniform attenuation correction. The original CT data are also utilized to correct for partial volume ef...

Journal: :AJR. American journal of roentgenology 2013
Yoon Kyung Kim Yon Mi Sung Jin Ho Choi Eun Young Kim Hyung Sik Kim

OBJECTIVE The objective of our study was to evaluate the effect of organ-based tube current modulation and bismuth shielding on image quality and breast radiation dose in women undergoing low-dose chest CT. SUBJECTS AND METHODS From March 2011 through July 2011, 80 women prospectively underwent low-dose chest CT to screen for lung cancer. The patients were randomly assigned to a control group...

Introduction: Recent studies of Computed Tomography (CT) conducted on patient dose reduction have recommended using an iterative reconstruction algorithm and mA (mili-Ampere) dose modulation. The current study aimed to evaluate Iterative Dose Reduction Algorithm (IDREAM) as an iterative reconstruction algorithm. Material and Methods: Two CT p...

Journal: :Medical physics 2004
William C Lavely Christopher Scarfone Hakan Cevikalp Rui Li Daniel W Byrne Anthony J Cmelak Benoit Dawant Ronald R Price Dennis E Hallahan J Michael Fitzpatrick

Radiotherapy treatment planning integrating positron emission tomography (PET) and computerized tomography (CT) is rapidly gaining acceptance in the clinical setting. Although hybrid systems are available, often the planning CT is acquired on a dedicated system separate from the PET scanner. A limiting factor to using PET data becomes the accuracy of the CT/PET registration. In this work, we us...

2000
Hidetaka Arimura Takuji Date Kaoru Morikawa Hideaki Kubota Masao Matsumoto Hitoshi Kanamori

For the optimization of the image quality of radiographs, the effect of the blur due to the scattered x rays on the image signal of radiographs has been ignored. The purpose of this study is to investigate the effect of the scattered x rays on the object sharpness of radiographs for tube voltages of 50 to 100 kV. For the purpose, using a phantom of the polymethyl methacrylate (PMMA) with an alu...

2014
Lei Fu Harold Perera Xiao Ying Yan Yu

The purpose of this study is to quantify the discrepancy between optical guidance platform (OGP) frameless localization system (Varian) and Trilogy on-board imaging (OBI) system (Varian) for setting up phantom and stereotactic radiosurgery (SRS) patient; and to determine whether cone-beam CT (CBCT) is necessary for OGP patient setup, and compare CBCT and orthogonal kV-kV in term of their verifi...

2014
Mana Akamatsu Yasuo Yamashita Go Akamatsu Yuji Tsutsui Nobuyoshi Ohya Yasuhiko Nakamura Masayuki Sasaki

OBJECTIVES The aim of this study was to evaluate the influences of reconstruction and attenuation correction on the differences in the radioactivity distributions in (123)I brain SPECT obtained by the hybrid SPECT/CT device. METHODS We used the 3-dimensional (3D) brain phantom, which imitates the precise structure of gray matter, white matter and bone regions. It was filled with (123)I soluti...

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