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Showing 1 to 20 of 64 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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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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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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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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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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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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DOSIMETRIC STUDY OF BETA-MINUS EMITTER PRASEODYMIUM-142 : APPLICATIONS IN MICROSPHERE BRACHYTHERAPY FOR HEPATOCELLULAR CARCINOMA AND BRACHYTHERAPY FOR OCULAR SQUAMOUS CELL CARCINOMA
… (19.12 h) allows this source to deliver high dose rates to the target. Penetration of the beta component of ¹⁴²Pr radiation in tissue is limited to a few millimeters, therefore limiting dose deposition to the treated site. The large neutron activation cross-section of the parent isotope (11.40 …
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Development and Evaluation of Advanced Dose Calculations for Modern Radiation Therapy Techniques
… fail to predict precisely the physical radiation dose distribution. Thus the clinical outcome of the treatment can not be properly evaluated by physicians. By using more sophisticated dose calculations based on superposition or Monte Carlo techniques this problem would be reduced or would actually …
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Synthesis and evaluation of radioactive gold nanoparticles for cancer treatment and imaging
… model of a human prostate, and then estimate the dose distribution that is deposited by radioactive gold nanoparticles (198AuNPs or 199AuNPs). The results from in vivo evalution of MGF-198AuNPs indicated that MGF-198AuNPs have significant therapeutic effect and they were able to control the tumor …
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A sensitivity-driven greedy approach to fluence map optimization in intensity-modulated radiation therapy
… sacrifices that can be tolerated in so-called dose-volume constraints. Efficiently imposing such constraints, which are fundamentally combinatorial in nature, poses a major challenge due to the large amount of data. Also, the IMRT technology limits which dose distributions are actually …
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