نتایج جستجو برای: scatter dose

تعداد نتایج: 321996  

Journal: :iranian journal of radiation research 0
m. akram department of physics, the islamia university of bahawalpur pakistan k. iqbal department of physics, the islamia university of bahawalpur pakistan m. isa department of physics, the islamia university of bahawalpur pakistan m. afzal department of physics, the islamia university of bahawalpur pakistan s.a. buzdar department of physics, the islamia university of bahawalpur pakistan

background: it was intended to investigate the effect of physical wedge (pw) and enhanced dynamic wedges (edw) on contralateral breast dose during primary breast irradiation in radiotherapy treatment, using high energy photon beams. materials and methods: the varian’s clinac dual mode linear accelerator model 2100 c/d and siemen’s primus accelerators were used for radiation doses with 6 mv and ...

Ahmad Mostaar, Ghazaleh Sadrieh Khajoo Mahdi Salehi Barough Mohammad Ali Ostadrahimi

Introduction: In the last few decades, a lot of monte carlo codes have been introduced for medical applications. this is important because through simulation, we are fully independent of the spectral scattering factor that we are not able measure in real terms. The effect of the radiation energy, the dimension of the radiation field, the sensitive volume of the ion chamber on t...

2013
Xue Dong Michael Petrongolo Tianye Niu Lei Zhu

Excessive imaging dose from repeated scans and poor image quality mainly due to scatter contamination are the two bottlenecks of cone-beam CT (CBCT) imaging. Compressed sensing (CS) reconstruction algorithms show promises in recovering faithful signals from low-dose projection data but do not serve well the needs of accurate CBCT imaging if effective scatter correction is not in place. Scatter ...

Journal: :Japanese Journal of Radiological Technology 1996

2015
Hiroaki Shimamoto Iori Sumida Naoya Kakimoto Keisuke Marutani Ryoko Okahata Ai Usami Tomomi Tsujimoto Shumei Murakami Souhei Furukawa Sotirios Tetradis

The presence of dental metals creates radiation dose perturbation due to scattered radiation during radiation therapy for the head and neck region. The purpose of our study was to compare the scatter doses resulting from various dental metals in the direction of the buccal mucosa among a single-field technique, three-dimensional conformal radiation therapy (3D CRT), and intensity-modulated radi...

Journal: :Physics in medicine and biology 2006
Oleg N Vassiliev Uwe Titt Falk Pönisch Stephen F Kry Radhe Mohan Michael T Gillin

Basic dosimetric properties of 6 MV and 18 MV photon beams from a Varian Clinac 21EX accelerator operating without the flattening filter have been measured. These include dose rate data, depth dose dependencies and lateral profiles in a water phantom, total scatter factors and transmission factors of a multileaf collimator. The data are reviewed and compared with measurements for the flattened ...

Journal: :iranian journal of nuclear medicine 2004
nasrollah jabbari hossein rajabi hassan firoozabadi fereidoon rastgoo nahid yaghoobi

introduction: scatter radiation is one of the major sources of error in nuclear medicine data processing. different methods of scatter correction have been introduced in order to improve the quality of data. however the best method is to avoid recording of scatter photons in acquisition. the only difference between scattered and non-scattered photons is the energy. pulse height analyzer is the ...

Journal: :Journal of X-ray science and technology 2011
Michael S Gossman Kunal J Paralikar Adam O Hebb Jeffrey D Wilkinson Alison R Graves-Calhoun Raymond C Lawson Jeffrey P Lopez James S Powell

OBJECT Where no society-based or manufacturer guidance on radiation limits to neuromodulation devices is available, this research provides the groundwork for neurosurgeons and radiation oncologists who rely on the computerized treatment plan clinically for cancer patients. The focus of the article is to characterize radiation parameters of attenuation and scatter when an incident therapeutic x-...

2016
Anna Kovalchuk Richelle Mychasiuk Arif Muhammad Shakhawat Hossain Yaroslav Ilnytskyy Abhijit Ghose Charles Kirkby Esmaeel Ghasroddashti Bryan Kolb Olga Kovalchuk

Irradiated cells can signal damage and distress to both close and distant neighbors that have not been directly exposed to the radiation (naïve bystanders). While studies have shown that such bystander effects occur in the shielded brain of animals upon body irradiation, their mechanism remains unexplored. Observed effects may be caused by some blood-borne factors; however they may also be expl...

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