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Machined brass skin collimation with variable thickness for electron therapy
Title
Machined brass skin collimation with variable thickness for electron therapy.
Creator
Gomez, Facenda Alianna, Ouhib, Zoubir, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description
Skin collimation in electron therapy ensures sharper penumbra and maximal protection to adjacent critical structures. It also provides a better clinical dose to the target and avoids recurrences at the periphery. The thickness of the electron skin collimation must be adequate for shielding purposes, not too thick to cause discomfort to the patient and be conformal to the skin. This study assessed the clinical potential of machined brass skin collimation with variable thickness. Brass...
Show moreSkin collimation in electron therapy ensures sharper penumbra and maximal protection to adjacent critical structures. It also provides a better clinical dose to the target and avoids recurrences at the periphery. The thickness of the electron skin collimation must be adequate for shielding purposes, not too thick to cause discomfort to the patient and be conformal to the skin. This study assessed the clinical potential of machined brass skin collimation with variable thickness. Brass transmission factors for 6, 9, and 12 MeV electron beams were measured and used to determine the skin collimation clinically acceptable thickness. Dosimetric performance of the variable thickness skin collimation was evaluated for 9 MeV electrons within a rectilinear water-equivalent phantom and a water-filled head phantom. Results showed the variable thickness skin collimation is dosimetrically equivalent to the uniform thickness collimation. Favorable dosimetric advantages for brass skin collimation for small electron fields were achieved.
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Date Issued
2021
PURL
http://purl.flvc.org/fau/fd/FA00013731
Subject Headings
Skin, Radiotherapy, Electron beams
Format
Document (PDF)
MODE-MODE COUPLING IN AN ELECTRON BEAM PLASMA
Title
MODE-MODE COUPLING IN AN ELECTRON BEAM PLASMA.
Creator
ELKMAN, WILLIAM ROBERT., Florida Atlantic University
Abstract/Description
A coherent nonlinear wave-wave coupling effect which is consistent with a more complete description of damping effects of a plane wave disturbance of a finite plasma initially spatially uniform and Maxwellian in velocity space is considered. A smeared out ion background is assumed and the coupling between the ions and electrons is neglected. A self consistent field and collective coordinate approach is used to obtain a dispersion relation for mode coupling in a plasma. The equations for the...
Show moreA coherent nonlinear wave-wave coupling effect which is consistent with a more complete description of damping effects of a plane wave disturbance of a finite plasma initially spatially uniform and Maxwellian in velocity space is considered. A smeared out ion background is assumed and the coupling between the ions and electrons is neglected. A self consistent field and collective coordinate approach is used to obtain a dispersion relation for mode coupling in a plasma. The equations for the amplitudes and the frequencies are solved numerically both by direct time integration and by a perturbation method for two and three modes. The perturbation method solutions are obtained for the n mode equations. The perturbation equations for two modes are solved analytically. For the two mode case the resulting coupling shows that the energy oscillates between the modes and that the periodicity of the amplitudes and the frequencies is associated with the initial parameters. Energy feeding between the modes is also observed for three or more modes. However, phase mixing occurs for more than two modes.
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Date Issued
1973
PURL
http://purl.flvc.org/fcla/dt/13593
Subject Headings
Coupled mode theory, Electron beams
Format
Document (PDF)
Validation of a Monte Carlo dose calculation algorithm for clinical electron beams in the presence of phantoms with complex heterogeneities
Title
Validation of a Monte Carlo dose calculation algorithm for clinical electron beams in the presence of phantoms with complex heterogeneities.
Creator
Enright, Shayla Landfair, Pella, Silvia, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description
The purpose of this thesis is to validate the Monte Carlo algorithm for electron radiotherapy in the Eclipse™ treatment planning system (TPS), and to compare the accuracy of the Electron Monte Carlo algorithm (eMC) to the Pencil Beam algorithm (PB) in Eclipse™. Dose distributions from GafChromic™ EBT3 film measurements were compared to dose distributions from eMC and PB treatment plans. Measurements were obtained with 6MeV, 9MeV, and 12MeV electron beams at various depths. A 1 cm thick solid...
Show moreThe purpose of this thesis is to validate the Monte Carlo algorithm for electron radiotherapy in the Eclipse™ treatment planning system (TPS), and to compare the accuracy of the Electron Monte Carlo algorithm (eMC) to the Pencil Beam algorithm (PB) in Eclipse™. Dose distributions from GafChromic™ EBT3 film measurements were compared to dose distributions from eMC and PB treatment plans. Measurements were obtained with 6MeV, 9MeV, and 12MeV electron beams at various depths. A 1 cm thick solid water template with holes for bone-like and lung-like plugs was used to create assorted configurations and heterogeneities. Dose distributions from eMC plans agreed better with the film measurements based on gamma analysis. Gamma values for eMC were between 83%-99%, whereas gamma values for PB treatment plans were as low as 38.66%. Our results show that using the eMC algorithm will improve dose accuracy in regions with heterogeneities and should be considered over PB.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004192
Subject Headings
Electron beams -- Therapeutic use, Image guided radiotherapy, Monte Carlo method, Proton beams -- Therapeutic use, Radiation dosimetry, Radiotherapy, High energy
Format
Document (PDF)