نتایج جستجو برای: dose distribution verification
تعداد نتایج: 975918 فیلتر نتایج به سال:
Background Fast and easily repeatable methods for commissioning procedures for brachytherapy (BT) treatment planning systems (TPS) are needed. Radiochromic film dosimetry with gamma analysis is widely used in external beam quality assurance (QA) procedures and planar film dosimetry is also increasingly used for verification of the dose distribution in BT applications. Using the gamma analysis m...
As is well-known from the literature on oligopolistic competition with incomplete information, firms have incentives to share private value demand information. However, by assuming verifiability of demand data, these models ignore the possibility of strategic misinformation. We show that if firms can send misleading demand information, they will always do so. Furthermore, we derive a costly sig...
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...
PURPOSE To present EBT2 film verification of treatment planning with the eXtend System, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery. METHODS A human head shaped phantom simulated the verification process for fractionated Gamma Knife (GK) treatment. Phantom preparation for eXtend Frame based treatment planning involved creating a dental impression, ...
PURPOSE Proton radiotherapy, with the ability to confine the dose at desired depth, can potentially benefit lung tumor patients by significantly sparing the healthy lung tissue. However, the superior proton dose distribution could be affected by tumor shrinkage due to the quick response and by motion especially related to the respiration. Thus the treatment should be frequently verified and be ...
The purpose of this study was to evaluate a single-scan protocol using Gafchromic EBT3 film (EBT3) by comparing it with the commonly used 24-hr measurement protocol for radiochromic film dosimetry. Radiochromic film is generally scanned 24 hr after film exposure (24-hr protocol). The single-scan protocol enables measurement results within a short time using only the verification film, one calib...
BACKGROUND To implement total body irradiation (TBI) using volumetric modulated arc therapy (VMAT). We applied the Varian RapidArc™ software to calculate and optimize the dose distribution. Emphasis was placed on applying a homogenous dose to the PTV and on reducing the dose to the lungs. METHODS From July 2013 to July 2014 seven patients with leukaemia were planned and treated with a VMAT-ba...
Introduction: In radiation therapy, accurate dose determination and precise dose delivery to the tumor are directly associated with better treatment outcomes in terms of higher tumor control and lower post radiation therapy complications. The current study aims the development and clinical application of the Patient Specific Quality Assurance (PSQA) procedures for nasopharyngea...
Introduction: The use of electronic portal imaging devices (EPIDs) is a method for the dosimetric verification of radiotherapy plans both pretreatment and in-vivo. The aim of this study was to test a 2D EPID-based dosimetry algorithm for dose verification of some plans inside a homogenous and anthropomorphic phantom and in-vivo, as well. Materials and Methods: </strong...
implicit and unobserved errors and vulnerabilities issues usually arise in cryptographic protocols and especially in authentication protocols. this may enable an attacker to make serious damages to the desired system, such as having the access to or changing secret documents, interfering in bank transactions, having access to users’ accounts, or may be having the control all over the syste...
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