نتایج جستجو برای: 3 d dosimetry
تعداد نتایج: 2222421 فیلتر نتایج به سال:
AAPM Task Group 119 has produced quantitative confidence limits as baseline expectation values for IMRT commissioning. A set of test cases was developed to assess the overall accuracy of planning and delivery of IMRT treatments. Each test uses contours of targets and avoidance structures drawn within rectangular phantoms. These tests were planned, delivered, measured, and analyzed by nine facil...
PURPOSE Well-known defect of TG-43 based algorithms used in brachytherapy is a lack of information about interaction cross-sections, which are determined not only by electron density but also by atomic number. TG-186 recommendations with using of MBDCA (model-based dose calculation algorithm), accurate tissues segmentation, and the structure's elemental composition continue to create difficulti...
1Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York; 2Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; 3Department of Nuclear Medicine, Philips-University of Marburg, Marburg, Germany; 4Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York; and 5Department of Radiology, School of Medicine, Jo...
• evaluate the accuracy of the calculation methods used in NEA Member countries for predicting long-term radiation doses to reactor pressure vessels and internal structures; • identify points for improvement and validate the performance of improved methods for fluence calculations; • initiate a study on the modelling of radiation-induced damage in metals. This report fulfils the first and secon...
BACKGROUND Peptide receptor radionuclide therapy (PRRT) plays an important role in the treatment of neuroendocrine tumors (NET). Pre-therapeutic dosimetry using the area under the measured time-activity curve (AUC) is important. The sampling schedule for this dosimetry determines the accuracy and reliability of the obtained AUC. The aim of this study was to investigate the effect of reduced num...
Background: The present work aims to study the out-of-field photon calculation accuracy of a commercial treatment planning system (TPS), Oncentra, for three-dimensional conformal radiotherapy (3D-CRT) and intensity modulated radiation therapy (IMRT) treatment techniques from Elekta Synergy medical linear accelerator. Materials and Methods: Accuracy of individual out-of-field dose components was...
The present paper addresses reference dose measurements using thimble ionization chambers for quality assurance in IMRT fields. In these radiation fields, detector fluence perturbation effects invalidate the application of open-field dosimetry protocol data for the derivation of absorbed dose to water from ionization chamber measurements. We define a correction factor C(Q)IMRT to correct the ab...
The purpose of this review is to summarize the peer-reviewed literature in relation to sunlight exposure assessment and the validity of using sunlight exposure questionnaires to quantify vitamin D status. There is greater variability in personal ultraviolet (UV) light exposure as the result of personal behavior than as the result of ambient UV light exposure. Although statistically significant,...
Amorphous silicon (a-Si) electronic portal imaging devices (EPIDs) are x-ray detectors frequently used in radiotherapy imaging and dosimetry applications. EPIDs employ a copper plate and gadolinium oxysulfide phosphor screen with an array of a-Si photodiodes to indirectly detect incident radiation. In this study, a previously developed Monte Carlo (MC) model of an aSi EPID has been extended for...
Radiation detection is essential for determining of radiation dose. Depend on the detector and dosimetry method, detection process is performed in different levels. Pulse counting is the first level of detection. Typically, the output of a radiation detector for determining value of the radiation dose cannot be used directly. Through changing the response function or the readout detector, is tr...
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