نتایج جستجو برای: Universal physical wedge

تعداد نتایج: 773679  

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: :Asian Pacific journal of cancer prevention : APJCP 2016
Azin Shamsi Mohammad Javad Tahmasebi Birgani Mohammad Ali Behrooz Sholeh Arvandi Jafar Fatahiasl Reza Maskny Neda Abdalvand

BACKGROUND 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 presented by the comb...

Journal: :iranian journal of radiation research 0
gh. geraily department of medical physics, tehran university of medical science, tehran, iran m. mirzapour department of electronic, east tehran branch, islamic azad university, tehran, iran s.r. mahdavi department of medical physics, tehran university of medical science, tehran, iran m. allahverdi department of medical physics, tehran university of medical science, tehran, iran a. mostaar department of biomedical engineering and medical physics, shahid beheshti university of medical science, tehran, iran m. masoudifar department of radiation oncology, mahak hospital, tehran, iran

background: physical wedges are still widely used as beam modifiers in external beam radiotherapy. however the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. the aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value l...

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...

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 ...

ژورنال: سنجش و ایمنی پرتو 2019

This research aimed to measure the received photon and thermal neutron doses to contralateral breast (CB) surface in breast cancer radiation therapy for different field sizes in presence of dynamic and physical wedges. The photon and thermal neutron doses were measured by thermo uminescent dosimeter (TLDs) chips for 11 × 13, 11 × 17 and 11 × 21 cm2 field sizes in presence of physical and dynamic ...

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...

1999
Sha X. Chang John P. Gibbons

A non-physical wedge generates a spatial dose distribution similar to that produced by a physical wedge without a physical filter in the photon beam. Instead, an exponential fluence profile is produced via motion of one of the collimating jaws. Proposed in the late 1970s, nonphysical wedges have been implemented on both Varian and Siemens’ accelerators as the Varian Dynamic Wedge (DW) and Sieme...

Journal: :Reports of practical oncology and radiotherapy : journal of Greatpoland Cancer Center in Poznan and Polish Society of Radiation Oncology 2011
Sathiyan Saminathan Ravikumar Manickam Sanjay S Supe

BACKGROUND Wedge filters can be used as missing tissue compensators or wedge pairs to alter the shape of isodose curves so that two beams can be angled with a small hinge angle at a target volume without creating a hotspot. AIM In this study the dosimetric properties of Varian Enhanced Dynamic Wedge (EDW) and physical wedges (PW) were analyzed and compared. MATERIALS AND METHODS Ionometric ...

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