Stopping‐power ratios for electron beams used in total skin electron therapy

2021 ◽  
Author(s):  
George X. Ding
Keyword(s):  
Electron Beams ◽  
Stopping Power ◽  
Electron Therapy

Run-aways im Neutralgas

1961 ◽  
Vol 16 (3) ◽  
pp. 246-252 ◽  
Author(s):  
G. Ecker ◽  
K. G. Müller
Keyword(s):  
Relaxation Time ◽  
Boltzmann Equation ◽  
Glow Discharge ◽  
Initial Velocity ◽  
Average Velocity ◽  
Electron Beams ◽  
Critical Value ◽  
Inelastic Collisions ◽  
Stopping Power ◽  
Scattering Parameters

The motion of electrons as determined by the field acceleration and the elastic and inelastic collisions with the gas atoms is calculated from the BOLTZMANN equation. We derive the average velocity and the scattering ellipsoid as a function of time. For particles starting from rest there exists always a critical electric field Ec depending on pressure and temperature. Below this critical value electrons approach the stationary drift process. Above the critical value the electrons do not reach a stationary state, they “run away”. For a finite initial velocity ν0 and a field below the critical value Ec the particles are either accelerated to drift, or decelerated to drift, or “run away”, depending on the value ν0. From a calculation of the scattering parameters we find for E > Ec a focussing effect in the velocity space which increases with field strength. Also the relaxation time for the drift process and the stopping power for electron beams can be calculated. Applications to the glow discharge are discussed.

Practical lookup tables for ensuring target coverage in a clinical setup for skin cancer electron therapy

2017 ◽  
Vol 17 (2) ◽  
pp. 205-211
Author(s):  
Yongsook C. Lee ◽  
Yongbok Kim
Keyword(s):  
Skin Cancer ◽  
Maximum Dose ◽  
Electron Beams ◽  
Target Coverage ◽  
Electron Beam Therapy ◽  
Surface Distance ◽  
Depth Dose ◽  
Electron Therapy ◽  
Lookup Tables ◽  
Output Factors

AbstractAimTo create practical lookup tables containing percent depth dose (PDD) and profile parameters of electron beams and to demonstrate clinical application of the lookup tables to skin cancer treatment to ensure target coverage in a clinical setup.Materials and methodsFor 6 and 9 MeV electron energies, PDDs and profiles at clinically relevant depths [i.e., R95 (distal depth of 95% maximum dose), R90, R85 and R80] were measured in water at 100 cm source-to-surface distance for an 10×10 cm2 open field and circular cutouts with diameters of 4, 5, 6, 7 and 8 cm. Then PDD parameters along with profile parameters such as width of isodose lines and penumbra at the clinically relevant depths were determined. Output factors for the cutouts were measured at dmax in water and solid water.ResultsWith PDD and profile parameters, dosimetry lookup tables were generated. Based upon the lookup tables, target coverage at prescribed depths was retrospectively reviewed for three skin cancer cases. The lookup tables suggested larger cutouts for adequate target coverage.FindingsDosimetry lookup tables for electron beam therapy should include profile parameters at clinically relevant depths and be provided to clinicians to ensure target coverage in a clinical setup.

RANGE AND STOPPING POWER ENERGY RELATIONSHIPS FOR 0.5–30 keV ELECTRON BEAMS SLOWING DOWN IN SOLIDS: ANALYTICAL MODEL

2013 ◽  
Vol 28 (01) ◽  
pp. 1450006 ◽  
Author(s):  
A. BENTABET
Keyword(s):  
Analytical Model ◽  
Electron Beams ◽  
Geometric Model ◽  
Mathematical Expression ◽  
Low Energy ◽  
Stopping Power ◽  
Slowing Down ◽  
Energy Relationships ◽  
Slight Discrepancy ◽  
Good Agreement

The development of an analytical model for calculating the electron stopping power (SP) converging with the experimental data at lower energies is still not completed. The purpose of this work is to suggest a mathematical expression of the range and the stopping power of electrons impinging in solid targets in the energy range up to 30 keV based on the spherical geometric model [A. Bentabet, Vacuum86 (2012) 1855]. The results are in good agreement with those of the literature. The slight discrepancy between the obtained and both the theoretical and experimental results regarding the stopping power at very low energy (E<0.5 keV) is discussed.

Calculation of stopping-power ratios using realistic clinical electron beams

1995 ◽  
Vol 22 (5) ◽  
pp. 489-501 ◽  
Author(s):  
G. X. Ding ◽  
D. W. O. Rogers ◽  
T. R. Mackie
Keyword(s):  
Electron Beams ◽  
Stopping Power

scholarly journals Towards MR-guided electron therapy: Measurement and simulation of clinical electron beams in magnetic fields

2020 ◽  
Vol 78 ◽  
pp. 83-92
Author(s):  
R. Kueng ◽  
B.M. Oborn ◽  
N.F. Roberts ◽  
T. Causer ◽  
M.F.M. Stampanoni ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Electron Beams ◽  
Electron Therapy
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