نتایج جستجو برای: treatment planning system out of field dose
تعداد نتایج: 21524488 فیلتر نتایج به سال:
BACKGROUND Radiotherapy plays an important role in the management of most malignant and many benign primary central nervous system (CNS) tumors. Radiotherapy affects both tumor cells and uninvolved normal cells; so, it is important to estimate absorbed dose to organs at risk in this kind of treatment. The aim of this study was to determine the absorbed dose to chiasma, lens, optic nerve, retina...
introduction: the complex geometry of breast and also lung and heart inhomogeneities near the planning target volume (ptv) result in perturbations in dose distribution. this problem can result in overdosage or underdosage in the match region of the three treatment fields. the purpose of this study is to create a homogeneous dose distribution in the match region between the supraclavicular and t...
what has been discussed here has been a study of international immigration law. this branch of law has not been a major player in the field of international law. no collective law exists, and no codification has been carried out as yet. however, the need for such a set of laws has forced the international community to pay more attention to this issue. the need for a better life in the so-call...
Introduction: Brachytherapy is a type of radiotherapy in which radioactive sources are used in proximity of tumors normally for treatment of malignancies in the head, prostate and cervix. Materials and Methods: The Cs-137 Selectron source is a low-dose-rate (LDR) brachytherapy source used in a remote afterloading system for treatment of different cancers. This system uses active and inactive sp...
Background: The purpose of this study was to evaluate nodal irradiation with conventional three-field's technique. Materials and Methods: Fifty patients with breast cancer were enrolled in this study. Computed tomography scans in the supine treatment position were imported into a treatment planning system. Levels I-III axillary and supraclavicular nodes were identified and their depths to the a...
Introduction: This study was aimed to investigate the beneficial effects of functional magnetic resonance imaging (fMRI) data in treatment planning for patients with CNS tumors in order to decrease the injury of functional regions of the brain followed by increase in life quality and survival of patients. This study pursues a novel approach in planning for the treatment of brai...
Introduction: Presence of dental filling material (DFM) such as amalgam in treatment patient with nasopharyngeal cancer (NPC) is common. Streaking artifact Arising from this high density material in computed tomography (scan), may lead to perturbation in dose calculation and dose delivery. Widespread performance of intensity-modulated radiotherapy (IMRT) for NPC using anterior...
plagiarism in esl/efl learning contexts has been established as a dynamic and multi-layered phenomenon and has become a topic engaging many researchers in a heated debate in recent years. comparisons of student-generated texts with their source texts have shown that students rely on source texts in their writings and copying is a major strategy used by both l1 and l2 writers. in our country a...
Background: One major challenge in brachytherapy is to verify the accuracy of dose distributions calculated by the treatment planning system. In this project, a new phantom design has been introduced for quality assurance of dose distributions in gynocological (GYN) brachytherapy implants using EBT GafChromic film. Materials and Methods: This phantom has been designed and fabricated from 90 sla...
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