نتایج جستجو برای: wedge
تعداد نتایج: 11897 فیلتر نتایج به سال:
In this research, numerical simulation of a symmetric impact of a 2-D wedge, considering dynamic equations in two-phase flow is taken into account. The two-phase flow around the wedge is solved based on finite volume method and volume of fluid (VOF) scheme. The dynamic mesh model is used to simulate dynamic motion of the wedge, thereby the effects of different dynamic meshes in both structured ...
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 ...
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...
A universal wedge filter of 15W × 20 cm(2) and 60° nominal wedge angle is designed and placed between the collimating jaws and penumbra trimmers inside the treatment head. A pneumatically driven actuating mechanism toggles the wedge between the wedge IN position and wedge OUT position. The effective wedge angles were determined using an analytical formula. An accumulated wedge profile at a dept...
triphalangeal thumb is characterized by the interposition of an extra-phalanx between two normal ones. in this article the authors present the case of a 24-year-old man with bilateral triphalangeal thumb of opposable type, without any other associated anomaly or genetic syndrome. the patient had triangular delta extra-phalanxes that caused ulnar deviation of both thumbs. surgical procedure for ...
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...
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BACKGROUND Theoretical considerations suggest that leg length increases after opening wedge high tibial osteotomy (HTO) and decreases after closing wedge HTO; however, in vivo studies have yielded conflicting results. This meta-analysis therefore assessed changes in leg length after opening wedge and closing wedge HTO. METHODS All studies comparing pre- and postoperative leg length in patient...
background: one of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment. objective: in the present study the impact of wedge and block on neutron contamination production is investigated. the evaluations are conducted for a 15 mv siemens primus linear accelerator. methods: simulations were performed using mcnpx mon...
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 bet...
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