نتایج جستجو برای: wedge factor

تعداد نتایج: 855483  

Estimation of the possible instability that may be encountered in the excavation slope(s) during the planning and application steps of the rock excavation processes is an important issue in geoengineering. In this paper, a modelling method is presented for assessing the probability of wedge failure involving new permanent or temporary slope(s) along the planned excavation dir...

ژورنال: مهندسی دریا 2012
جواهریان, محمد جواد, حسنی چالکسرا, احسان, زراعتگر, حمید, یوسف نژاد, رضا,

Analysis of wedge water entry as a basic problem has wide application. Model testing is a powerful means to deal with the said problem. In this study, a set of water entry tests on wedges of 20, 30 and 40 degrees deadrise angles has been conducted and the pressure distributions are recorded. Free falling method in symmetry conditions are considered in this research. A parametric study on pressu...

Introduction: Physical wedge by modify photon beam shape and intensity has been utilized in radiotherapy to obtain uniformly dose distribution in tumor site with reduced hot spots. Calculation of dosimetric parameters for both symmetric and asymmetric wedged fields is proved necessary during linear accelerator (Linac) commissioning. The present study aimed to achieve o...

ژورنال: توانبخشی 2016

Objective Osteoarthritis is a degenerative disease of joints that causes degeneration and corrosion of joint surface. Because of osteoarthritis, the smooth and even movemvement of joints get interrupted. Osteoarthritis is the most common kind of arthritis and its prevalence is 19.3% in Iran. Patients with knee osteoarthritis usually have geno varum and hyperpronation of foot. The...

Journal: :iranian journal of radiation research 0
m. momennezhad nuclear medicine research center, emam reza hospital, mashhad university of medical sciences, mashhad, iran m.t. bahreyni toosi medical physics research center, mashhad university of medical sciences, mashhad, iran r. sadeghi nuclear medicine research center, emam reza hospital, mashhad university of medical sciences, mashhad, iran h. gholamhoseinian department of medical physics, medical school, mashhad university of medical sciences, mashhad, iran sh. nasseri department of medical physics, medical school, mashhad university of medical sciences, mashhad, iran

background: the presence of a wedge filter in the beam trajectory can modify the beam quality and cause some changes in the dosimetry parameters which are usually difficult to be measured directly and accurately. material and methods: in this study the mcnp-4c monte carlo code was used to simulate the 9 mv photon beam generated by a linear accelerator. upon getting a good agreement between the ...

2005
Richard A. Popple Ivan A. Brezovich Jun Duan Sui Shen Prem N. Pareek Sung‐Joon Ye

Some modern treatment-planning systems (TPSs) provide for input of wedge factor (WF) tables covering the entire range of square and elongated fields available on the LINAC. Depending on the field size increment chosen and the number of available wedge orientations, one may have to take more than 100 measurements per wedge and photon energy to commission the TPS. To expedite TPS commissioning wh...

Journal: :iranian journal of medical physics 0
mohammad javad t ahmasebi associated professor, medical physics & radiotherapy dept., golestan hospital, ahwaz university of medical sciences, ahwaz, iran mohammad ali behrooz professor, medical physics dept., ahwaz university of medical sciences, ahwaz, iran shole arvandi assistant professor, radiotherapy & oncology dept., golestan hospital, ahwaz university of medical sciences, ahwaz, iran davood khezerloo m.sc. medical physics dept., ahwaz university of medical sciences, ahwaz, iran mojtaba karbalai m.sc. medical physics dept., golestan hospital, ahwaz university of medical sciences, ahwaz, iran

introduction: nowadays,  considerable developments  in  the field  of  radiotherapy have  been  achieved.  they  include  the  advances  made  in  the  equipments  and  treatment  planning  techniques  which  require  highly complex calculations. such achievements have made it possible to treat cancer patients not only  with  higher  radiation  dose  but  also  with  higher  precision  and  con...

Azin Shamsi Jafar Fatahiasl Mohammad Ali Behrooz Mohammad Javad Tahmasebi Birgani Neda Abdalvand Reza Maskny Shole Arvandi

Introduction: Wedge filters are commonly used in radiation oncology for eliminating hot spots and creating a uniform dose distribution in optimizing isodose curves in the target volume for clinical aspects. These are some limited standard physical wedges (15°, 30°, 45°, 60°), or creating an arbitrary wedge angle, like motorized wedge or dynamic wedge, ... The new formulation is...

Journal: :iranian journal of radiation research 0
h. acar department of radiation oncology, selcuklu faculty of medicine, selcuk university, turkey g. yavas department of radiation oncology, selcuklu faculty of medicine, selcuk university, turkey c. yavas department of radiation oncology, konya training and research hospital, turkey

background: in radiation therapy, the peripheral dose is important when anatomical structures with very low dose tolerances are involved. in this study, the two available calculation algorithms of the varian eclipse 8.6 treatment planning system(tps), the anisotropic analytic algorithm (aaa) and pencil-beam convolution (pbc) was used to compare measured and calculated peripheral dose distributi...

Fathollah Bouzarjomehri Mahdie Behjati Mohammad Amin Mosleh-Shirazi, Mostafa Sohrabpour Seyed Pezhman Shirmardi,

Introduction: Wedge filters are used in radiotherapy to modify photon beam and improve dose uniformity in the target volume. Determination of wedge dose distribution is important to improve treatment planning accuracy. The utilization of treatment planning software to obtain dose distribution is not always available. In this work an analytical model has been developed to calcu...

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