نتایج جستجو برای: high energy photon beam
تعداد نتایج: 2686543 فیلتر نتایج به سال:
The secondary positron beams produced by linear electron accelerators are used in scattering experiments with stationary targets, in electron-positron colliding beam experiments, and in the production of annihilation photon beams : they now approach primary electron beams in their energy, intensity, and range of application. (To be published in physics Today) Work supported by the U.S. Atomic E...
This paper investigates a method of reconstructing images from energy-resolved CT data with negligible beam-hardening artifacts and improved contrast-to-nosie ratio (CNR) compared to conventional energy-weighting methods. Conceptually, the investigated method first reconstructs separate images from each energy bin. The final image is a linear combination of the energy-bin images, with the weigh...
High-intensity x-ray pulses from an x-ray free-electron laser are used to heat and probe a solid-density aluminum sample. The photon-energy-dependent transmission of the heating beam is studied through the use of a photodiode. Saturable absorption is observed, with the resulting transmission differing significantly from the cold case, in good agreement with atomic-kinetics simulations.
The interference of Deeply Virtual Compton Scattering (DVCS) and Bremsstrahlung leads to a beam-charge asymmetry that can be observed for exclusive photon production in the collision of high energy leptons and nucleons/nuclei. Recent results for a hydrogen and a deuterium target are reported and a consistent tendency for a rise of the cosine φ coefficient with momentum transfer |t| has been found.
PURPOSE The aim of this work was to comprehensively evaluate a new large field ion chamber transmission detector, Integral Quality Monitor (IQM), for online external photon beam verification and quality assurance. The device is designed to be mounted on the linac accessory tray to measure and verify photon energy, field shape, gantry position, and fluence before and during patient treatment. ...
Background: This paper aimed to analyze the output constancy of a medical linear accelerator using PTW QUICKCHECKwebline and studied the sensitivity of the PTW QUICKCHECKwebline. Materials and Methods: The paper statistically analyzed the output doses of 6 MV and 10 MV of photons and 6 MeV, 9 MeV, and 12 MeV of electrons from a medical linear accelerator measured before the daily treatment to ...
This study presents the beam data measurement results from the commissioning of three TrueBeam linear accelerators. An additional evaluation of the measured beam data within the TrueBeam linear accelerators contrasted with two other linear accelerators from the same manufacturer (i.e., Clinac and Trilogy) was performed to identify and evaluate any differences in the beam characteristics between...
For the production of a clinical 15 MV photon beam, the design of accelerator head assembly has been optimized using Monte Carlo based FLUKA code. The accelerator head assembly consists of etarget, flattening filter, primary collimator and an adjustable rectangular secondary collimator. Accelerators used for medical radiation therapy generate continuous energy gamma rays called bremsstrahlung r...
Introduction: One of scientific concern is increasing of unwanted neutron dose to the patient, in head and neck radiation therapy due to the presence of some isotopes in dental restorations and head of medical linac. The aim of this study is to measure the equivalent dose of thermal and fast neutron due to head of Siemens Primus Linac and a healthy tooth, Amalgam, Ni-Cr alloy a...
ID: 1109 Title: Integral Dose in External Beam Photon Radiotherapy Integral dose is the volume integral of the dose deposited in the patient and is equal to the mean dose times the volume. The integral dose is also the area under the curve of a differential dose absolute-volume histogram. It is widely believed that IMRT increases the integral dose to normal tissues as compared to conventional r...
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