Depth-dose and stopping-power data for mono-energetic electron beams

1990 ◽  
Vol 51 (2) ◽  
pp. 107-121 ◽  
Author(s):  
Pedro Andreo
Keyword(s):  
Electron Beams ◽  
Energetic Electron ◽  
Stopping Power ◽  
Depth Dose

scholarly journals Dosimetric Characterization of Small Radiotherapy Electron Beams Collimated by Circular Applicators with the New Microsilicon Detector

2022 ◽  
Vol 12 (2) ◽  
pp. 600
Author(s):  
Serenella Russo ◽  
Silvia Bettarini ◽  
Barbara Grilli Leonulli ◽  
Marco Esposito ◽  
Paolo Alpi ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Electron Beams ◽  
High Energy ◽  
Field Size ◽  
The Novel ◽  
Linear Accelerators ◽  
Depth Dose ◽  
Dosimetric Data ◽  
Output Factors ◽  
Dose Measurements

High-energy small electron beams, generated by linear accelerators, are used for radiotherapy of localized superficial tumours. The aim of the present study is to assess the dosimetric performance under small radiation therapy electron beams of the novel PTW microSilicon detector compared to other available dosimeters. Relative dose measurements of circular fields with 20, 30, 40, and 50 mm aperture diameters were performed for electron beams generated by an Elekta Synergy linac, with energy between 4 and 12 MeV. Percentage depth dose, transverse profiles, and output factors, normalized to the 10 × 10 cm2 reference field, were measured. All dosimetric data were collected in a PTW MP3 motorized water phantom, at SSD of 100 cm, by using the novel PTW microSilicon detector. The PTW diode E and the PTW microDiamond were also used in all beam apertures for benchmarking. Data for the biggest field size were also measured by the PTW Advanced Markus ionization chamber. Measurements performed by the microSilicon are in good agreement with the reference values for all the tubular applicators and beam energies within the stated uncertainties. This confirms the reliability of the microSilicon detector for relative dosimetry of small radiation therapy electron beams collimated by circular applicators.

scholarly journals Benchmarking of Siemens Linac in Electron Modes: 8-14 MeV Electron Beams

2018 ◽  
Vol 8 (2) ◽  
Author(s):  
H Dowlatabadi ◽  
A A Mowlavi ◽  
M Ghorbani ◽  
S Mohammadi ◽  
F Akbari
Keyword(s):  
Monte Carlo ◽  
Radiation Treatment ◽  
Electron Beams ◽  
Dose Profile ◽  
Depth Dose ◽  
Mcnpx Code ◽  
Gamma Index ◽  
Simulation Results ◽  
Mc Simulation ◽  
Good Agreement

Introduction: Radiation therapy using electron beams is a promising method due to its physical dose distribution. Monte Carlo (MC) code is the best and most accurate technique for forespeaking the distribution of dose in radiation treatment of patients.Materials and Methods: We report an MC simulation of a linac head and depth dose on central axis, along with profile calculations. The purpose of the present research is to carefully analyze the application of MC methods for the calculation of dosimetric parameters for electron beams with energies of 8–14 MeV at a Siemens Primus linac. The principal components of the linac head were simulated using MCNPX code for different applicators. Results: The consequences of measurements and simulations revealed a good agreement. Gamma index values were below 1 for most points, for all energy values and all applicators in percent depth dose and dose profile computations. A number of states exhibited rather large gamma indices; these points were located at the tail of the percent depth dose graph; these points were less used in in radiotherapy. In the dose profile graph, gamma indices of most parts were below 1. The discrepancies between the simulation results and measurements in terms of Zmax, R90, R80 and R50 were insignificant. The results of Monte Carlo simulations showed a good agreement with the measurements. Conclusion: The software can be used for simulating electron modes of a Siemens Primus linac when direct experimental measurements are not feasible.

scholarly journals Applications and benefits of using gradient percentage depth dose instead of percentage depth dose for electron and photon beams in radiotherapy

2021 ◽  
Vol 27 (1) ◽  
pp. 25-29
Author(s):  
Labinot Kastrati ◽  
Gezim Hodolli ◽  
Sehad Kadiri ◽  
Elvin Demirel ◽  
Lutfi Istrefi ◽  
...  
Keyword(s):  
Electron Beams ◽  
Published Data ◽  
Photon Beams ◽  
Data Set ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Electron And Photon

Abstract Introduction: The aim of this study is to analyze the gradient of percentage depth dose for photon and electron beams of LINACs and to simplify the data set. Materials and Methods: Dosimetry measurements were performed in accordance with Technical Reports Series No. 398 IAEA. Results and discussion: The gradient of percentage depth dose was calculated and compared with the available published data. Conclusion: Instead of percentage depth dose for increasing and decreasing parts, the findings suggest using only two numbers for specific gradient of dose, separately. In this way, they can replace the whole set of the percentage depth dose (PDD).

scholarly journals Commissioning Measurements of Electron Beam Using Montecarlo Algorithm on Truebeam STx® and Compariaon with Clinac iX Linear Accelerator

2021 ◽  
Vol 229 ◽  
pp. 01041
Author(s):  
Kamal Saidi ◽  
Redouane El Baydaoui ◽  
Hanae El Gouach ◽  
Othmane Kaanouch ◽  
Mohamed Reda Mesradi
Keyword(s):  
Electron Beam ◽  
Electron Beams ◽  
Measured Data ◽  
University Hospital ◽  
Field Size ◽  
Large Field ◽  
Water Phantom ◽  
Depth Dose ◽  
International University ◽  
The Absolute

TrueBeam STx latest generation linear accelerators (linacs) installed at Sheikh Khalifa International University Hospital in Casablanca, Morocco. The aim of this is to present and compare the result of the Electron commissioning measurement on TrueBeam Stx and clinac iX installed at Sheikh Khalifa International University Hospital in Casablanca, Morocco. A compariaon of eMC calculations and measurements for TrueBeam Stx were evaluated. Dosimetric parameters are systematically measured using a large water phantom 3D scanning system MP3 Water Phantom (PTW, Freiburg, Germany). The data of the electron beams commissioning including depth dose curves for each applicator, depth dose curves without applicator and the profile in air for a large field size 40x 40cm2, and the Absolute Dose (cGy/MU) for each applicator. All the data were examined and compared for five electron beams (E6MeV, E9MeV, E12MeV, E16MeV and E20MeV) of Varian’s TrueBeam STx and Clinac iX machines. A comparison, between measurement PDDs and calculated by the Eclipse electron Monte Carlo (eMC) algorithm were performed to validate Truebeam Stx commissioning. All this measurements were performed with a Roos and Markus plane parallel chamber. Our measured data indicated that electron beam PDDs from the TrueBeam Stx machine are well matched to those from our Varian Clinac iX machine. Significant differences between TrueBeam and Clinac iX were found in in‐air profiles and open field output. Maximum depth dose for the TrueBeam Stx and Clinac iX for the following energies (6, 9, 12, 16, 20 MeV) are respectively (1.15; 1.89; 2.6; 3.1; and 2.35) and (1.24; 1.95; 2.70; 2.99 and 2.4cm). For the TrueBeam Stx and Clinac iX the quality index R50 for applicator 15x15 cm2 are in the tolerance intervals. Surface dose increases by increasing energy for both machines. The Absolute Dose (cGy/MU) calibrated for both machine in Dmax at 1cGy/MU for the reference field size cone 15x15 cm2. Bremsstrahlung tail Rp per energy levels as follows for the TrueBeam Stx : 6 MeV – 2.85 cm, 9 MeV – 4.28 cm, 12 MeV – 5.97 cm, 16 MeV – 7.88 cm and 20 MeV – 9.86 cm. and for the Clinac iX : 6 MeV – 2.86 cm, 9 MeV – 4.32 cm, 12 MeV – 5.96 cm, 16 MeV – 7.93 cm and 20 MeV – 10.08 cm. A good agreement between modeled and measured data is observed.

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.

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