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Author  |
Valdes-Cortez, C.; Niatsetski, Y.; Perez-Calatayud, J.; Ballester, F.; Vijande, J. |
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Title |
A Monte Carlo study of the relative biological effectiveness in surface brachytherapy |
Type |
Journal Article |
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Year |
2022 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
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Volume |
49 |
Issue |
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Pages |
5576-5588 |
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Keywords |
Monte Carlo; relative biological effectiveness; surface HDR brachytherapy |
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Abstract |
Purpose This work aims to simulate clustered DNA damage from ionizing radiation and estimate the relative biological effectiveness (RBE) for radionuclide (rBT)- and electronic (eBT)-based surface brachytherapy through a hybrid Monte Carlo (MC) approach, using realistic models of the sources and applicators. Methods Damage from ionizing radiation has been studied using the Monte Carlo Damage Simulation algorithm using as input the primary electron fluence simulated using a state-of-the-art MC code, PENELOPE-2018. Two Ir-192 rBT applicators, Valencia and Leipzig, one Co-60 source with a Freiburg Flap applicator (reference source), and two eBT systems, Esteya and INTRABEAM, have been included in this study implementing full realizations of their geometries as disclosed by the manufacturer. The role played by filtration and tube kilovoltage has also been addressed. Results For rBT, an RBE value of about 1.01 has been found for the applicators and phantoms considered. In the case of eBT, RBE values for the Esteya system show an almost constant RBE value of about 1.06 for all depths and materials. For INTRABEAM, variations in the range of 1.12-1.06 are reported depending on phantom composition and depth. Modifications in the Esteya system, filtration, and tube kilovoltage give rise to variations in the same range. Conclusions Current clinical practice does not incorporate biological effects in surface brachytherapy. Therefore, the same absorbed dose is administered to the patients independently on the particularities of the rBT or eBT system considered. The almost constant RBE values reported for rBT support that assumption regardless of the details of the patient geometry, the presence of a flattening filter in the applicator design, or even significant modifications in the photon energy spectra above 300 keV. That is not the case for eBT, where a clear dependence on the eBT system and the characteristics of the patient geometry are reported. A complete study specific for each eBT system, including detailed applicator characteristics (size, shape, filtering, among others) and common anatomical locations, should be performed before adopting an existing RBE value. |
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Address |
[Valdes-Cortez, Christian] Hosp Reg Antofagasta, Nucl Med Dept, Antofagasta, Chile, Email: cvalcort@gmail.com |
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Publisher |
Wiley |
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English |
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ISSN |
0094-2405 |
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Notes |
WOS:000811709400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5262 |
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Author |
Vijande, J.; Granero, D.; Perez-Calatayud, J.; Ballester, F. |
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Title |
Monte Carlo dosimetric study of the medium dose rate CSM40 source |
Type |
Journal Article |
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Year |
2013 |
Publication |
Applied Radiation and Isotopes |
Abbreviated Journal |
Appl. Radiat. Isot. |
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Volume |
82 |
Issue |
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Pages |
283-288 |
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Keywords |
Brachytherapy; Cs-137 seed; TG-43 based dosimetry; Monte Carlo |
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Abstract |
The Cs-137 medium dose rate (MDR) CSM40 source model (Eckert & Ziegler BEBIG, Germany) is in clinical use but no dosimetric dataset has been published. This study aims to obtain dosimetric data for the CSM40 source for its use in clinical practice as required by the American Association of Physicists in Medicine (AAPM) and the European Society for Radiotherapy and Oncology (ESTRO). Penelope2008 and Geant4 Monte Carlo codes were used to characterize this source dosimetrically. It was located in an unbounded water phantom with composition and mass density as recommended by AAPM and ESTRO. Due to the low photon energies of Cs-137, absorbed dose was approximated by collisional kerma. Additional simulations were performed to obtain the air-kerma strength, sic. Mass-energy absorption coefficients in water and air were consistently derived and used to calculate collisional kerma. Results performed with both radiation transport codes showed agreement typically within 0.05%. Dose rate constant, radial dose function and anisotropy function are provided for the CSM40 and compared with published data for other commercially available Cs-137 sources. An uncertainty analysis has been performed. The data provided by this study can be used as input data and verification in the treatment planning systems. (C) 2013 Elsevier Ltd. All rights reserved. |
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Address |
[Vijande, J.; Ballester, F.] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Spain, Email: Javier.vijande@uv.es |
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Pergamon-Elsevier Science Ltd |
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English |
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ISSN |
0969-8043 |
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Notes |
WOS:000328804000043 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
1678 |
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Author |
Zhang, X.; Xiao, Y.T.; Gimeno, B. |
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Title |
Multipactor Suppression by a Resonant Static Magnetic Field on a Dielectric Surface |
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Journal Article |
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Year |
2020 |
Publication |
IEEE Transactions on Electron Devices |
Abbreviated Journal |
IEEE Trans. Electron Devices |
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Volume |
67 |
Issue |
12 |
Pages |
5723-5728 |
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Keywords |
Radio frequency; Dielectrics; Magnetic resonance; Discharges (electric); Surface discharges; Surface waves; Electrostatics; Monte Carlo simulation; multipactor discharge; orthogonal waves; resonant static magnetic field; secondary electron yield |
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Abstract |
In this article, we study the suppression of the multipactor phenomenon on a dielectric surface by a resonant static magnetic field. A homemade Monte Carlo algorithm is developed for multipactor simulations on a dielectric surface driven by two orthogonal radio frequency (RF) electric field components. When the static magnetic field is perpendicular to the tangential and normal RF electric fields, it is shown that if the normal electric field lags the tangential electric field by pi/2, the superposition of the normal and tangential electric fields will trigger a gyro-acceleration of the electron cloud and restrain the multipactor discharge effectively. By contrast, when the normal electric field is in advance of the tangential electric field by pi/2, the difference between the normal and tangential electric fields drives gyro-motion of the electron cloud. Consequently, two enhanced discharge zones are inevitable. The suppression effects of the resonant static magnetic field that is parallel to the tangential RF electric field or to the normal RF electric field are also presented. |
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Address |
[Zhang, Xue; Xiao, Yuting] Xiangtan Univ, Sch Automat & Elect Informat, Xiangtan 411105, Hunan, Peoples R China, Email: zhangxue.iecas@yahoo.com; |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
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Language |
English |
Summary Language |
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ISSN |
0018-9383 |
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Notes |
WOS:000594337700064 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4627 |
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