نتایج جستجو برای: head scatter factor sc medical accelerator mini phantom

تعداد نتایج: 1631298  

Journal: :Medical physics 2014
Ida Häggström C Ross Schmidtlein Mikael Karlsson Anne Larsson

PURPOSE The aim of this study was to investigate the effect of scatter and its correction on kinetic parameters in dynamic brain positron emission tomography (PET) tumor imaging. The 2-tissue compartment model was used, and two different reconstruction methods and two scatter correction (SC) schemes were investigated. METHODS The gate Monte Carlo (MC) software was used to perform 2 × 15 full ...

ژورنال: سنجش و ایمنی پرتو 2020

Radiotherapy using linear accelerators is known as an effective modality for cancer treatment. The photons energy of treatment beams significantly affect the dose distribution. Therefore, it is important to accurately evaluate the photon energy spectra. In this study, MCNPX Monte Carlo code (version 2.6.0) was used to simulate an 18 MV photon beam of a Varian 2100C/D linear accelerator. By matc...

Journal: :iranian journal of nuclear medicine 2013
mohsen hajizadeh saffar shabnam oloomi peter knoll hadi taleshi

introduction: scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. accurate estimation of scatter in projection data of spect is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. methods: the objective of this paper is to develop and validate a scatter correction technique ...

Hadi Taleshi Mohsen Saffar Peter Knoll, Shabnam Oloomi

Introduction: Scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. Accurate estimation of scatter in projection data of SPECT is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. Methods: The objective of this paper is to develop and validate a scatter correction technique ...

2018
Chalinee Thanasupsombat Saowapak S Thongvigitmanee Sorapong Aootaphao Pairash Thajchayapong

The quality of images obtained from cone-beam computed tomography (CBCT) is important in diagnosis and treatment planning for dental and maxillofacial applications. However, X-ray scattering inside a human head is one of the main factors that cause a drop in image quality, especially in the CBCT system with a wide-angle cone-beam X-ray source and a large area detector. In this study, the X-ray ...

Journal: :Journal of nuclear medicine technology 2003
Douglass C Vines Masanori Ichise Jeih-San Liow Hiroshi Toyama Robert B Innis

OBJECTIVE Scatter correction is an important factor in quantitative SPECT. In this study, we evaluated 2 methods of scatter correction for brain SPECT. The first is based on thresholding the energy spectrum (ES), and the second is based on a modification of the transmission-dependent convolution subtraction (TDCS) method. METHODS SPECT imaging of a skull striatal phantom was performed using a...

Journal: :NeuroImage 2003
Marie-Louise Montandon Daniel O Slosman Habib Zaidi

It is recognized that scatter correction can supply more accurate absolute quantification, and that iterative reconstruction results in better noise properties and significantly reduces streak artefacts; however, it is not entirely clear whether they produce significant changes in [18F]-FDG distribution of reconstructed 3D brain PET images relative to not scatter corrected images and analytic r...

Journal: :علوم پیراپزشکی و بهداشت نظامی 0
سید سلمان ذکریایی seyed salman zakariaee department of radiology, faculty of paramedicine, aja university of medical sciences, tehran, iranگروه رادیولوژی، دانشکده ی پیراپزشکی، دانشگاه علوم پزشکی ارتش، تهران، ایران. ولی اله صبا valiallah saba department of radiology, faculty of paramedicine, aja university of medical sciences, tehran, iranگروه رادیولوژی، دانشکده ی پیراپزشکی، دانشگاه علوم پزشکی ارتش، تهران، ایران.

introduction: in diagnostic and therapeutic procedures, dosimetric studies are performed on the dosimetric systems in order to comply the radiation safety standards. monte carlo methods are used due to the high complexity and cost of patient-specific phantom construction. the high complexity of the digitized phantoms greatly increases the time and computational task of the monte carlo calculati...

Journal: :Medical physics 2012
James L Robar David Parsons Avery Berman Alex Macdonald

PURPOSE This is a proof-of-concept study addressing volume of interest (VOI) cone beam CT (CBCT) imaging using an x-ray beam produced by 2.35 MeV electrons incident on a carbon linear accelerator target. Methodology is presented relevant to VOI CBCT image acquisition and reconstruction. Sample image data are given to demonstrate and compare two approaches to minimizing artifacts arising from re...

ژورنال: سنجش و ایمنی پرتو 2019

Human tissue equivalent phantoms are widely used in medicine. They are used for dosimetry, calibration of medical devices, and quality control of radiotherapy equipment, as well as training students. Regarding to development of radiotherapy techniques for treatment of cancers and also development of educational centers in the country, the human equivalent phantoms are needed. Several phantoms h...

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