نتایج جستجو برای: kilovoltage

تعداد نتایج: 427  

2018
Christophe Furstoss

The Canadian Organization of Medical Physicists (COMP) in close partnership with the Canadian Partnership for Quality Radiotherapy (CPQR) has developed a series of Technical Quality Control (TQC) guidelines for radiation treatment equipment. These guidelines outline the performance objectives that equipment should meet in order to ensure an acceptable level of radiation treatment quality. The T...

Journal: :Medical physics 2006
Martin J Butson Tsang Cheung Peter K N Yu

Gafchromic XRCT, radiochromic film is assessed over a broad energy range, from kilovoltage to megavoltage x rays for variations in reflected optical density to dose response. A large energy dependence was found with reflected optical density output for the same delivered dose varying from 7.8±0.35 at 25.5keV (50kVp) peaking at 12.1±0.5 at 54keV (125kVp) to 0.975±0.03 at 2300keV (10MV) when norm...

2015
Nam P. Nguyen Ulf Lennart Karlsson

During most of the last century, verification of patient position on the radiotherapy treatment table was considered adequate if exposed on a photographic film by a megavoltage beam. It was a general standard to expose such a film once a week, to be approved by a radiation oncologist. The latter approved it after comparison to a kilovoltage simulation film exposed at the time of initial setup o...

2014
Kenshiro Shiraishi Masahiko Futaguchi Akihiro Haga Akira Sakumi Katsutake Sasaki Kentaro Yamamoto Hiroshi Igaki Kuni Ohtomo Kiyoshi Yoda Keiichi Nakagawa

Time-averaged intreatment prostate localization errors were calculated, for the first time, by three-dimensional prostate image cross-correlation between planning CT and intrafraction kilovoltage cone-beam CT (CBCT) during volumetric modulated arc therapy (VMAT). The intrafraction CBCT volume was reconstructed by an inhouse software after acquiring cine-mode projection images during VMAT delive...

Journal: :AJR. American journal of roentgenology 1980
R E Latchaw J T Payne R B Loewenson

Thirty-eight enhancing intracranial neoplasms were evaluated with a dual kilovoltage technique to measure the change of effective atomic number (delta Z), and linear attenuation coefficients with the use of iodinated contrast material. The change of effective atomic number was found to separate intracranial neoplasms into three major groups: gliomas, meningiomas, and metastases. Other parameter...

2017
Gerben R. Borst

Purpose: Kilovoltage cone-beam computed tomography (CBCT) has been developed to provide accurate soft-tissue and bony setup information. We evaluated clinical CBCT setup data and compared CBCT measurements with electronic portal imaging device (EPID) images. Material and Methods: The setup error for CBCT scans at the treatment unit relative to the planning CT was measured for 62 patients (524 s...

2012
Joerg Lehmann Stanley Skubic

Precise targeting of the tumor is very important and imaging can be immensely helpful in this process. Hence the quality assurance of the imaging systems used to guide the beam is also essential. One could argue that it is as critical as quality assurance for the radiation dose output, since the right amount of radiation dose delivered to the wrong location can be as detrimental as delivering t...

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