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Showing 1 to 20 of 70 for “"dose distribution"”.
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Comparison of Tumor Shrinkage and Cumulative Dose Distribution For Lung Cancers
… is that they deliver most of their radiation dose to the target volume and deliver no dose to the normal tissue distal to the tumor. Previously, numerous studies have shown unique advantages of proton therapy over intensity-modulated radiation therapy (IMRT) in conforming dose to the tumor and …
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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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Analysis of a Low Pressure UV reactor under Multiple Upstream Elbow Configurations using UV Sensitive Fluorescent Microspheres
… influence of upstream configuration on the UV dose distribution has not been experimentally investigated. This research was performed to evaluate the UV reactor dose distribution under multiple upstream configurations using UV sensitive fluorescent microspheres. The upstream hydraulics …
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Improved Calculation and Display for Dose Distributions Associated With Intrauterine Radiotherapy.
A computer program has been developed for dose distribution calculations associated with an intrauterine applicator. The program reconstructs the exact source positions from two orthogonal x-ray projections. The dosages delivered to reference points A and B are calculated. In addition, isodose …
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Radiobiology of normal rat lung in Boron Neutron Capture Therapy
… beam facility was found to provide a suitable dose distribution for this project. A delimiter was designed and constructed for the rat lung irradiations as a lithiated-polyethylene plate of 1.5 cm thickness with an aperture tapered from 4 to 3 cm in width to expose the lung to the beam and …
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Beyond The Dvh - Spatial And Biological Radiotherapy Treatment Planning
… biological parameters and retains spatial dose information.</p> <p><strong>Methods</strong>: A software system named SABER (<strong>S</strong>patial <strong>A</strong>nd <strong>B</strong>iological <strong>E</strong>valuation for <strong>R</strong>adiotherapy) is developed which provides …
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Measured dose distributions of iodine-125 sources and the computerised optimisation of their positions in brachytherapy planning
… and becoming increasingly varied. The spatial dose distributions around two types of 1-125 seeds in general use, were measured using a Geiger-Muller chamber. Seeds with the 1-125 adsorbed onto resin spheres had a 10% less anisotropic dose distribution than seeds containing a silver wire with …
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Geometric Algorithms and Data Structures for Simulating Diffusion Limited Reactions
… in radiation therapy is the estimation of dose distribution in the treated patient, which is key to determining the treatment outcome and potential side effects of the therapy. Biological dose — the level of biological damage (e.g., cell killing ratio, DNA damage, etc.) inflicted by the …
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3D Scintillator Detector Quenching Characterization For Scanning Proton Beams
… proton pencil beams provide a highly conformal dose distribution. The complex dose distribution poses challenges for quality assurance measurements leading to sophisticated detector setups and time consuming measurements. Fast 3D measurements are therefore desirable to verify the complex dose …
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A Complete Dosimetric Model of the Gamma Knife Perfexion Using Penelope Monte Carlo Codes
… damage to the target structure while minimizing dose to adjacent healthy tissue. Tungsten collimators are organized into eight sectors of 24 sources each; each sector can be set to one of three collimation sizes. The collimators can produce nominal spheres of dose 16 mm, 8 mm, or 4 mm in diameter …
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Direct optimization of 3D dose distributions using collimator rotation
… plan without compromising the quality of the dose distribution. It is also shown that an arrangement of equispaced collimator angles takes full advantage of the flexibility associated with collimator rotation. A study including ten recurring nasopharynx cancer patients is used to evaluate the …
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Image-Guided Proton Therapy For Online Dose-Evaluation and Adaptive Planning
… will affect the proton range and the resultant dose distribution, making it difficult to estimate the impact of visible anatomic changes to the patient dose distribution. In order to better understand the effect of anatomy change on proton dose, some form of treatment-time verification is …
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Verification of The Clinical Implementation of The Respiratory Gated Beam Delivery Technique With Synchrotron-Based Proton Irradiation
… high-energy x-rays stems from their unique depth-dose distribution, which delivers essentially no dose beyond the end of range. In order to achieve it, accurate localization of the tumor volume relative to the proton beam is necessary. For cases where the tumor moves with respiration, the …
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Enhancement of the Real-Time Dose Tracking System for Interventional Fluoroscopic Procedures through Monte Carlo Investigations
… time and patients can receive relatively high dose, thus the inherent risks that must be evaluated and minimized. We have previously developed a dose tracking system (DTS) to provide a real-time color-coded 3D-mapping of skin dose. The purpose of this work is to add the capability to determine …
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Microdosimetry of radiohalogens in thyroid models
… advantages, for example, by enabling relevant biodistribution and dosimetric studies important for dose-planning before radionuclide therapy. 211At, with its relatively long half-life, stable daughter nuclide, and production and labelling possibilities is considered as one of the most attractive …
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Evaluation of Intensity Modulated Radiation Therapy (Imrt) Delivery Error Due to Imrt Treatment Plan Complexity and Improperly Matched Dosimetry Data
… is a technique that delivers a highly conformal dose distribution to a target volume while attempting to maximally spare the surrounding normal tissues. IMRT is a common treatment modality used for treating head and neck (H&N) cancers, and the presence of many critical structures in this region …
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Incorporating range uncertainty into proton therapy treatment planning
… they are traversing, resulting in a steep dose gradient at the distal edge of the Bragg peak. These characteristics, together with advancements in computation and technology have led to the ability to plan and deliver treatments with greater conformality, sparing normal tissue and organs at …
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Dose analysis of the Model 112A Pulserad Pulsed X-Ray Generator by ITS/CYLTRAN.
… beam parameters such as beam radius and angular distribution. A previously unexplained measured dip in the radiation dose at the beam center line can be explained with an angular divergence of the electron beam from the cathode. The simulation is successful in explaining the pattern of the dose …
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Readout of polymer gel dosimeters using a prototype fan-beam optical computed tomography scanner
… curve was less capable of describing PAGAT dose response than a quadratic calibration curve. Intra-gel calibration using another dose distribution was shown to be no less accurate than self calibration, but inter-gel calibrations saw a statistically significant increase in absolute readout …
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Volumetric, Magnetic Resonance-Visible, and Radiation-Sensitive Detectors For Magnetic Resonance Image-Guided Radiation Therapy
… the magnetic field cause perturbations of the dose distribution in three dimensions. Current vendor-supplied electronic quality assurance tools can provide at best quasi-3D sampling of the dose distribution and cannot be MR imaged. As a result, there was a growing need for volumetric, …
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