Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 37 for “"dose calculation"”.
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Dose Calculation For Electron Therapy
<p>The dose delivered by electron beams has a complex dependence on the shape of the field; any field shaping shields, design of collimator systems, and energy of the beam. This complicated dependence is due to multiple scattering of the electron beam as the beam travels from the accelerator head …
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Pencil beam dose calculation for proton therapy on graphics processing units
… protons enables greater conformity between the dose distribution and the tumour than conventional radiotherapy using X rays. However, the dose distributions are more sensitive to changes in patient anatomy, and tend to deteriorate in the presence of motion. Online dose calculation during …
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Reduction of Dose Calculation Errors For Patients With Metal Implants Receiving Photon Radiation Therapy
… these metal implants can degrade the accuracy of dose calculations. Dose calculation errors result from limitations of modern dose calculation algorithms in modeling metal/tissue interface effects. Metals also cause streak artifacts in the computed tomography (CT) images that are used for …
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Influence on different Monte-Carlo variances at the dose calculation and the impact to the commissioning
… is gradually being introduced for clinical dose computation in the quest to improve the accuracy of predicting the dose distribution to a medium from a given beam setup. Dosimetric measurement is used to verify the accuracy of the calculated dose distribution before the beam setup can be …
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Development of A New Independent Monte Carlo Dose Calculation Quality Assurance Audit to ol For Clinical Trials
… (TPS) may use a number of different radiation dose calculation algorithms during the planning process. The Radiological Physics Center (RPC), tasked with ensuring clinically comparable and consistent dose delivery amongst institutions participating in NCI funded multi-institutional clinical …
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Benchmarking and Implementation of A New Independent Monte Carlo Dose Calculation Quality Assurance Audit to ol For Clinical Trials
… treatment planning systems employ a variety of dose calculation algorithms to plan and predict the dose distributions a patient receives during external beam radiation therapy. Traditionally, the Radiological Physics Center has relied on measurements to assure that institutions participating in …
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Development and application of a multi-modality inverse treatment planning system
… a very high computional speed only simplified dose calculation algorithms are used. Furthermore, approximations are made during the calculation of the fluence matrix. This thesis develops an IMRT planning tool which can be used with any available radiation modality and makes use of improved …
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Patient safety and Errors in Veterinary Anesthesia
… Medicine (UCVM). The third study evaluated dose calculation errors, while the fourth study assessed the effectiveness of an anesthesia safety checklist in reducing incomplete safety tasks. Medication errors were found to be the most commonly reported error in veterinary medicine. A …
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Improving Dose Calculations In Electron-beam Radiation Therapy
… tumour sites. However, the simplistic methods of dose calculation in current clinical use lack sufficient accuracy in many situations of clinical importance. This thesis rests on the premise that a more accurate dose calculation method must incorporate all the major physical processes which shape …
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Thoracic Radiotherapy Treatment Planning With Cine Pet/Ct
… 4D-CT for the purposes of target delineation and dose calculation, and to explore the role of PET in target delineation of lung cancer. Methods: To determine whether cine CT could substitute 4D-CT for small mobile lung tumors, we compared target volumes delineated by a physician on cine CT and …
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Quantifying The Magnitude of to tal Dose Deviation Caused By Various Sources of Error Among Iroc Phantom Irradiation Results
… are treated like patients, and evaluation of the doses received by the thermoluminescent dosimeters (TLDs) inside the phantom, reflects the accuracy with which an institution can image, plan and irradiate a phantom or patient. Recent phantom results show that among the hundreds of various IROC …
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Volumetric Modulated Arc Therapy Evaluation With The Radiological Physics Center Head and Neck Phantom
<p>Validation of treatment plan quality and dose calculation accuracy is essential for new radiotherapy techniques, including volumetric modulated arc therapy (VMAT). VMAT delivers intensity modulated radiotherapy treatments while simultaneously rotating the gantry, adding an additional level of …
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Characterization of Treatment Planning System Photon Beam Modeling Errors In Iroc Houston Phantom Irradiations
… of the treatment planning system’s (TPS) dose calculation algorithm is critical because any errors in this process impact all treatment plans prepared in the system. Previously, TPS errors have been identified as a major cause for poor phantom irradiation performance, which may also mean …
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Proton Computed Tomography: a novel calibration approach for proton treatment planning
… radiotherapy modality offering superior dose localization and reduced damage to healthy tissues, made possible by the unique physical characteristics of protons. Accurate prediction of proton range during treatment planning is critical to its success. However, current methods relying on …
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Multicriteria Optimization in Inverse Radiotherapy Planning
… enhanced the possibilities of shaping the dose distribution. However, because of physical limitations, even with IMRT a certain dose to organs at risk is unavoidable, so in treatment planning often a compromise between different plan criteria has to be found. This thesis presents a new …
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Characterization of Oslds For Use In Small Field Photon Beam Dosimetry
… various correction factors associated with OSLD dose calculations. The uncertainties for each correction factor were also investigated. It was determined that the linearity, depletion, fading, and energy correction factors were identical to the RPC commissioning data for non-masked OSLDs. The …
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Evaluation of The Effectiveness of Anisotropic Analytical Algorithm In Flattened and Flattening-Filter-Free Beams For High Energy Lung Dose Delivery Using The Radiological Physics Center Lung Phantom
… Volume (PTV) received 100% of the prescribed dose while ensuring that normal tissue constraints were followed as well. Calculated doses were exported from the Eclipse TPS and compared with the experimental data as measured using thermoluminescence detectors (TLD) and radiochromic films that …
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Optimization of Image Guided Radiation Therapy for Lung Cancer Using Limited-angle Projections
… acquisition enables scan time and imaging dose reduction and improves the mechanical clearance of imaging.</p><p>First of all, the dissertation developed a phase-matched digital tomosynthesis (DTS) technique using limited-angle (<=30 deg) projections for lung tumor localization. This …
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