نتایج جستجو برای: scatter dose

تعداد نتایج: 321996  

Journal: :AJR. American journal of roentgenology 2002
Jerry N King Anna M Champlin Charles A Kelsey David A Tripp

OBJECTIVE The purpose of this paper is to show the effectiveness of a new radiation protection method designed to decrease the amount of scatter radiation received by practitioners performing procedures under fluoroscopic guidance. MATERIALS AND METHODS A sterile, disposable, lead-free surgical drape containing radiation protection material composed primarily of bismuth was evaluated for effe...

M. Allahverdi, M. Hoseini-Ghahfarokhi, M. Shahriari, M. Zabihzadeh, M.R. Ay, S.R. Mahdavi,

Background: During intensity modulated radiation therapy (IMRT) technique, theoretically, presence of flattening filter (FF) across the beamline of clinical linear accelerator (linac) is not essential to obtain uniform lateral profiles due to intensity modulation of photon beams by multileaf collimators (MLCs). The aim of this study was to investigate the dosimetrical properties of 18 MV photon...

Bachground: Hadron therapy is a novel technique of cancer radiation therapy which employs charged particles beams, 1H and light ions in particular. Due to their physical and radiobiological properties, they allow one to obtain a more conformal treatment, sparing better the healthy tissues located in proximity of the tumor and allowing a higher control of the disease.  Objective: As it is well ...

Mansour Zabihzadeh Mohammad Reza Ay, Mojtaba Hoseini- Ghahfarokhi Seyed Rabee Mahdavi

Introduction: During intensity modulated radiation therapy (IMRT) technique, theoretically, presence of flattening filter (FF) across the beamline of clinical linear accelerator (linac) is not essential to obtain uniform lateral profiles due to intensity modulation of photon beams by multileaf collimators (MLCs). The aim of this study was to investigate the dosimetrical propert...

F Shahedi, H Gholamhosseinian M H Bahreyni M Mohammadi, M Momennezhad, R Salek, S Bayani, S M Hashemi, S Nasseri

Background: The present study aimed to introduce a rapid transmission dosimetry through an electronic portal-imaging device (EPID) to achieve two-dimensional (2D) dose distribution for homogenous environments. Material and Methods: In this Phantom study, first, the EPID calibration curve and correction coefficients for field size were obtained from EPID and ionization chamber. Second, the...

Journal: :Clinical journal of oncology nursing 2015
Susan Doyle-Lindrud

Although major advances have been made in radiation techniques, concerns still exist about the treatment-related acute and long-term side effects. This issue is most notable in the pediatric population because of developing organs and tissues combined with longer life expectancies. Proton beam therapy has the advantage of a reduced dose of radiation with less scatter to normal tissue, which may...

Journal: :Clinical science 1995
A T Cole N M Garlick A M Galvin C J Hawkey R A Robins

1. We report a flow cytometric method in which changes in forward angle light scatter are shown to correlate with microscopically evaluated shape change in stimulated human neutrophils. Neutrophil movement and chemotaxis is conventionally measured using Boyden chambers, which is a laborious and exacting technique. Microscopic scoring of neutrophil shape change has been shown to correlate well w...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2008
Masanobu Ibaraki Shuichi Miura Eku Shimosegawa Shigeki Sugawara Tetsuro Mizuta Akihiro Ishikawa Masaharu Amano

UNLABELLED Quantitative PET with (15)O provides absolute values for cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rate of oxygen (CMRO(2)), and oxygen extraction fraction (OEF), which are used for assessment of brain pathophysiology. Absolute quantification relies on physically accurate measurement, which, thus far, has been achieved by 2-dimensional PET (2D PET), t...

Journal: :Journal of radiological protection : official journal of the Society for Radiological Protection 2013
S A Mitchell C J Martin

Doses for panoramic dental radiography are assessed in terms of the dose-width product (DWP) or dose-area product, which gives a measure of the radiation through a whole exposure. The DWP can be measured using a pencil ionisation chamber (IC) similar to that used for computed tomography dose assessment. However, ICs are sensitive to radiation incident from all directions and so backscatter from...

Journal: :Medical physics 2009
Lei Zhu Yaoqin Xie Jing Wang Lei Xing

Cone-beam CT (CBCT) is being increasingly used in modern radiation therapy for patient setup and adaptive replanning. However, due to the large volume of x-ray illumination, scatter becomes a rather serious problem and is considered as one of the fundamental limitations of CBCT image quality. Many scatter correction algorithms have been proposed in literature, while a standard practical solutio...

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