نتایج جستجو برای: photon dose measurement
تعداد نتایج: 796871 فیلتر نتایج به سال:
Introduction: Background: Radiotherapy of parotid tumors is achieved by different radiotherapy techniques. So they deliver the dose to organs at risk such as contralateral parotid, temporal lobe & spinal cord. The consequences of high dose to OARs are xerostomia, Temporal lobe necrosis and loss of hearing. Purpose: The aim of this study was to compare different treatment tech...
Introduction: Physical wedge as a useful tool has been utilized in radiotherapy to modify photon beam shape and intensity such that it distributes dose uniformly in tumor site and reduces hot points. Since during Linac commissioning dosimetric parameters like output factors and lateral dose profiles are measured only for symmetric open and wedged fields, so calculation the par...
In radiation therapy with high-energy photon beams (E > 10 MV) neutrons are generated mainly in LINACs head thorough (γ,n) interactions. These neutrons affect the shielding requirements in radiation therapy rooms. According to the AAPMTG-34 report, photon absorbed dose of 10Gy can cause permanent damage to the pacemaker and the dose of 2Gy can make minor changes in the functioning of the pac...
Introduction: Many studies have shown the effects of delivered dose distribution due to the incident photon energy on the tumor and healthy tissues. The ability to access the most appropriate radiation energy is essential to achieve the optimal treatment planning but there is a serious limitation in number of energies available on radiation therapy machines can restrict it. <s...
INTRODUCTION AND PURPOSE Conventional x-ray films and radiochromic films have inherent challenges for high precision radiotherapy dosimetry. Here we have investigated basic characteristics of optically stimulated luminescence (OSL) of irradiated films containing carbon-doped aluminum oxide (Al2O3:C) for dosimetry in therapeutic photon and electron beams. MATERIALS AND METHODS The OSL films co...
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 ...
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 and purpose: Beam shaper is a type of applicator used in conjunction with the intraoperative electron radiotherapy. This study aimed at quantitative evaluation of the photon contamination of this applicator using Monte Carlo simulation. Materials and methods: In this experimental study, at first the head of LIAC accelerator was simulated along with the beam shaper applicator using...
Background: The present study aimed to investigate the equivalent dose in vital organs, including heart and lung, due to secondary particles produced during breast proton therapy. Materials and Methods: The numerical ORNL female-phantom was improved and simulated using the Monte Carlo MCNPX code. The depth-dose profile of proton beams with different energies was simulated. The proper energy ran...
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