Article
Physics, Multidisciplinary
Antonio Bianchi
Summary: The increasing interest in environmental-friendly gas mixtures for gaseous particle detectors has led to the need for simulating electron transport coefficients and reaction rates in these mixtures. MATOQ is a Monte Carlo simulation program specifically designed for this purpose and allows for the simulation of electron avalanches in gaseous detectors.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Mohamad Alissa, Klemens Zink, Ralf-Peter Kapsch, Andreas A. A. Schoenfeld, Stephan Frick, Damian Czarnecki
Summary: This study aimed to determine the correction factors kB,Q for ion chambers in the presence of external magnetic fields in high-energy photon fields. The results showed that the magnitude of the correction factor depends on the chamber volume and orientation, and the preferred chamber orientation is when the magnetic field direction and the chamber axis coincide and are perpendicular to the beam direction. The correction factors can be applied in clinical reference dosimetry for existing MRI-linear accelerators.
Article
Chemistry, Inorganic & Nuclear
Hamid Reza Baghani, Mostafa Robatjazi, Stefano Andreoli
Summary: The performance characteristics of different parallel-plate ionization chambers in dosimetry of high energy electron beams were evaluated, with Roos and Advanced Markus chambers showing superior performance. All considered ionization chambers met the criteria requested by relevant reference dosimetry protocols.
APPLIED RADIATION AND ISOTOPES
(2022)
Article
Engineering, Biomedical
M. McManus, F. Romano, G. Royle, D. Botnariuc, D. Shipley, H. Palmans, A. Subiel
Summary: A detailed characterization of the Roos secondary standard plane-parallel ionization chamber was conducted in a novel 200 MeV Very High Energy Electron (VHEE) beam, with reference to the standard 12 MeV electron calibration beam used in experimental work. Stopping-power ratios, perturbation factors, and beam quality correction factor were determined and calculated using the Geant4 MC code. The results showed good agreement between the 12 MeV electron calibration beam and current dosimetry protocols, while the VHEE beam had lower variations. The beam quality correction factors were found to reduce the calculated dose by approximately 10%.
PHYSICS IN MEDICINE AND BIOLOGY
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Mohamad Alissa, Klemens Zink, Frederic Tessier, Andreas A. Schoenfeld, Damian Czarnecki
Summary: This study aimed to calculate beam quality correction factors kQ for SNC600c and SNC125c ionization chambers, comparing the results with published kQ values for similar chambers, demonstrating a high level of agreement.
PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Kilian-Simon Baumann, Sina Kaupa, Constantin Bach, Rita Engenhart-Cabillic, Klemens Zink
Summary: This study determined perturbation correction factors for six plane-parallel and four cylindrical ionization chambers in clinical proton beams using Monte Carlo simulations. The results showed that the total perturbation correction factor was smaller than unity for almost every ionization chamber and proton energy, with significant differences in some cases.
ZEITSCHRIFT FUR MEDIZINISCHE PHYSIK
(2021)
Article
Construction & Building Technology
Marcin Koniorczyk, Witold Grymin
Summary: The article investigates the impact of uncertainties in building energy demand calculations, comparing the perturbation stochastic finite element method to Monte Carlo results and finding the former to be more efficient. Variance in temperature is observed to be highest at the node between the constructive layer and insulation in the wall.
Article
Engineering, Biomedical
Alexandra Bourgouin, Jose Paz-Martin, Yunus Can Gedik, Franziska Frei, Peter Peier, Severine Rossomme, Andreas A. Schonfeld, Andreas Schuller, Faustino Gomez Rodriguez, Ralf-Peter Kapsch
Summary: This study experimentally determined the charge collection efficiency (CCE) of six commercially available parallel-plate ionisation chamber (PPIC) models in ultra-high dose-per-pulse electron beams. The results showed significant intra- and inter-model variations, which could not be solely explained by electrode spacing deviation. This research is important for research and pre-clinical study, but further model development is needed for clinical applications.
PHYSICS IN MEDICINE AND BIOLOGY
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
J. Sempau, P. Kazantsev, J. Izewska, L. Brualla
Summary: The IAEA has operated a global postal dosimetry audit program for radiotherapy centers in collaboration with the WHO since 1969. In 2017, a new methodology based on radiophotoluminescent dosimetry was introduced for these audits.
PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS
(2021)
Article
Engineering, Biomedical
Yuka Urago, Makoto Sakama, Dousatsu Sakata, Shigekazu Fukuda, Tetsurou Katayose, Weishan Chang
Summary: In this study, kQ values were calculated in four cylindrical chambers and two plane-parallel chambers using Monte Carlo simulations. The calculated kQ ratios were validated through comparisons against measured values. The kQ uncertainty was reduced from 3% to 1.7%, and the P values varied between different chamber types.
PHYSICS IN MEDICINE AND BIOLOGY
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Miguel Lopez-Sanchez, Maria Perez-Fernandez, Eduardo Pardo, Jose M. Fandino, Antonio Teijeiro, Nicolas Gomez-Fernandez, Faustino Gomez, Diego M. Gonzalez-Castano
Summary: This study used Monte Carlo simulation to evaluate the response of the four smallest active volume ionization chambers when measuring SRS cone collimated FFF fields. The IBA RAZOR Nano Chamber was found to be an excellent choice for narrow beam output factor measurement due to its minimum correction requirement and advantages of tiny size and tissue equivalence materials.
PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS
(2022)
Article
Physics, Particles & Fields
L. Norman, K. Silva, B. J. P. Jones, A. D. McDonald, M. R. Tiscareno, K. Woodruff
Summary: In this study, the dielectric breakdown strengths of several important time projection chamber working gases were experimentally investigated. A theoretical model based on microphysical simulations was developed, which showed high predictive capability for high pressure breakdown and accurate predictions for noble gases and insulating gases.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Yue-Houng Hu, Hok Seum Wan Chan Tseung, Daniel W. Mundy
Summary: Dental fixtures are commonly used in radiation treatment for older patients. This study investigated the physical effects of delivering proton beams through dental materials, with the goal of determining the feasibility of using treatment geometries not specified for avoidance of oral implants. Various dental materials were evaluated in terms of stopping power and dose perturbation.
Article
Radiology, Nuclear Medicine & Medical Imaging
Gunther H. Hartmann, Pedro Andreo, Ralf-Peter Kapsch, Klemens Zink
Summary: The study focuses on the determination of absorbed dose using a converted energy per mass (cema)-based approach, which offers a good understanding of detector response under various measuring conditions. The research demonstrates that the cema approach is particularly useful under non-reference conditions. Correction factors can be expressed and evaluated by cema ratios comprehensively, providing insights for the selection of detectors for specific measurement situations.
Article
Physics, Multidisciplinary
Julian Roers, Damian Czarnecki, Mohamad Alissa, Klemens Zink
Summary: The aim of this study is to investigate the depth-dependent detector response of detailed thimble air-filled ionization chambers. Spectral charged particle fluence correction factors at different depths were calculated to analyze the variations in detector response and the influences of different effects on the spectral response.
FRONTIERS IN PHYSICS
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Yuri Simeonov, Uli Weber, Christoph Schuy, Rita Engenhart-Cabillic, Petar Penchev, Marco Durante, Klemens Zink
Summary: This paper introduces the concept of a 2D range-modulator as a static device for generating spread-out Bragg peaks at very small distances to the target. The advantages and manufacturing process of the 2D range-modulator are discussed, with different rapid prototyping techniques used for polymer and steel modulators. The study demonstrates that the modulator can create highly homogeneous spread-out Bragg peaks, making it a useful tool for various research objectives.
ZEITSCHRIFT FUR MEDIZINISCHE PHYSIK
(2021)
Review
Radiology, Nuclear Medicine & Medical Imaging
Martin Fiebich, Andreas Block, Markus Borowski, Lilli Geworski, Christian Happel, Alexandra Kamp, Horst Lenzen, Andreas H. Mahnken, Wolfgang-Ulrich Mueller, Gebhard Oestreicher, Frank Rudolf, Georg Stamm, Peter Starck, Beatrice Steiniger, Jan-Henryk Wicke, Ulrich Wolf, Michael Wucherer, Maria Zankl, Klemens Zink, Claudia Zweig
Summary: This review provides guidance on assessing the exposure of pregnant women to X-rays and determining the dose to the unborn child. In general, the use of X-rays in pregnant women in radiology should be avoided, with alternatives or postponement of examinations recommended. Low radiation exposures under 20 mSv are typically found in the vast majority of cases in X-ray diagnostics for the unborn child, with higher doses only occurring in a few types of examinations.
ROFO-FORTSCHRITTE AUF DEM GEBIET DER RONTGENSTRAHLEN UND DER BILDGEBENDEN VERFAHREN
(2021)
Article
Radiology, Nuclear Medicine & Medical Imaging
Kilian-Simon Baumann, Sina Kaupa, Constantin Bach, Rita Engenhart-Cabillic, Klemens Zink
Summary: This study determined perturbation correction factors for six plane-parallel and four cylindrical ionization chambers in clinical proton beams using Monte Carlo simulations. The results showed that the total perturbation correction factor was smaller than unity for almost every ionization chamber and proton energy, with significant differences in some cases.
ZEITSCHRIFT FUR MEDIZINISCHE PHYSIK
(2021)
Article
Engineering, Biomedical
Kilian-Simon Baumann, Larissa Derksen, Matthias Witt, Jan Michael Burg, Rita Engenhart-Cabillic, Klemens Zink
Summary: This study provides Monte Carlo calculated beam quality correction factors for monoenergetic proton beams and compared them with experimentally determined values, showing good agreement at the 1% level, with a need for further investigation of differences between Monte Carlo codes for high energies.
PHYSICS IN MEDICINE AND BIOLOGY
(2021)
Article
Radiology, Nuclear Medicine & Medical Imaging
Mohamad Alissa, Klemens Zink, Frederic Tessier, Andreas A. Schoenfeld, Damian Czarnecki
Summary: This study aimed to calculate beam quality correction factors kQ for SNC600c and SNC125c ionization chambers, comparing the results with published kQ values for similar chambers, demonstrating a high level of agreement.
PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Thomas Failing, Gunther H. Hartmann, Frank W. Hensley, Boris Keil, Klemens Zink
Summary: Simulation of absorbed dose deposition in a detector is crucial for Monte Carlo dosimetry, and recent research has shown that upgrading codes can significantly enhance efficiency. The modified egs_chamber code provides accurate charged particle fluence spectra calculations, demonstrating feasibility and efficiency gains in simulations.
ZEITSCHRIFT FUR MEDIZINISCHE PHYSIK
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Yuri Simeonov, Uli Weber, Christoph Schuy, Rita Engenhart-Cabillic, Petar Penchev, Veronika Flatten, Klemens Zink
Summary: The study aimed to develop and manufacture a 3D range-modulator for scanned proton therapy, which showed promising results in producing highly homogeneous dose distributions that are comparable to standard IMPT. Monte Carlo simulations were used to investigate its modulating properties and dose distribution, and the results were validated with measurements at a treatment center. The concept of the 3D range-modulator combines high dose homogeneity and conformity with very short irradiation times, providing a clinically applicable dose distribution for lung and/or FLASH treatment.
BIOMEDICAL PHYSICS & ENGINEERING EXPRESS
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Stephanie Schade, Rita Engenhart-Cabillic, Klemens Zink, Damian Czarnecki
Summary: This study developed an algorithm to correct the image of an electronic portal imaging device (EPID) for dosimetric purposes, investigating the impact of field size, phantom thickness, and spectral photon distribution on the EPID image. The algorithm showed promising results in correcting these influences and enabling high-precision dose measurements. By using multiple correction factors, the EPID image can be easily adjusted for other linear accelerators and configurations.
JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Damian Czarnecki, Klemens Zink, Mohamad Alissa, Veronika Flatten, Teresa Espelage, Andreas A. Schoenfeld
Summary: This study investigated the ability of the IC Profiler detector array to measure photon beam quality and developed a Monte Carlo-based model for validation. The results showed that the Monte Carlo simulations were consistent with the measurements, demonstrating the reliability of the model. Furthermore, the model can be used for further research on the effects of beam parameter variations on AR ratios and %dd(10)x$_\textrm {{\it x}}$.
Article
Radiology, Nuclear Medicine & Medical Imaging
Leon Baack, Christoph Schuy, Stephan Brons, Felix Horst, Bernd Voss, Klemens Zink, Thomas Haberer, Marco Durante, Uli Weber
Summary: This study investigates the recombination loss of different fill gases in plane parallel ionisation chambers and develops a numerical model for simulating the space charge effect. The results show that He/CO2 mixtures allow accurate beam monitoring at high intensities, and adding CO2 decreases ion mobility but increases breakdown voltage.
PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Julian Roers, Damian Czarnecki, Mohamad Alissa, Klemens Zink
Summary: The aim of this study is to investigate the depth-dependent detector response of detailed thimble air-filled ionization chambers. Spectral charged particle fluence correction factors at different depths were calculated to analyze the variations in detector response and the influences of different effects on the spectral response.
FRONTIERS IN PHYSICS
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Mohamad Alissa, Klemens Zink, Ralf-Peter Kapsch, Andreas A. A. Schoenfeld, Stephan Frick, Damian Czarnecki
Summary: This study aimed to determine the correction factors kB,Q for ion chambers in the presence of external magnetic fields in high-energy photon fields. The results showed that the magnitude of the correction factor depends on the chamber volume and orientation, and the preferred chamber orientation is when the magnetic field direction and the chamber axis coincide and are perpendicular to the beam direction. The correction factors can be applied in clinical reference dosimetry for existing MRI-linear accelerators.
Article
Engineering, Biomedical
Larissa Derksen, Veronika Flatten, Rita Engenhart-Cabillic, Klemens Zink, Kilian-Simon Baumann
Summary: In this study, the authors used Monte Carlo track structure simulations to investigate the effect of inter-track interactions on the yield of chemicals produced by ionizing particles. The results suggest that inter-track interactions may explain the reduced normal tissue toxicity observed in FLASH radiotherapy.
PHYSICS IN MEDICINE AND BIOLOGY
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Jan Michael Burg, Veronika Flatten, Joerg Wulff, Beate Timmermann, Hilke Vorwerk, Klemens Zink
Summary: It has been discovered that water and PMMA emit a weak luminescence signal when irradiated with protons within the clinically used energy range. A setup for high-resolution spectral measurement of the luminescence signal in water and PMMA was designed in this work. The results show that the signal originates from excited states produced during the radiolysis of water and there are differences in the spectra between water and PMMA. The findings provide a foundation for further research on proton range verification.
BIOMEDICAL PHYSICS & ENGINEERING EXPRESS
(2023)
Article
Engineering, Biomedical
Kilian-Simon Baumann, Larissa Derksen, Matthias Witt, Sebastian Adeberg, Klemens Zink
Summary: This study investigates the influence of different versions of the Monte Carlo codes geant4 and fluka on the calculation of overall response functions f(Q) of air-filled ionization chambers in clinical proton beams. The results show that there can be differences of up to 1% in the f(Q) factors calculated with different versions of the same Monte Carlo code. The updated version of geant4 leads to a more pronounced dependence of f(Q) on proton energy and smaller f(Q) factors for high energies.
PHYSICS IN MEDICINE AND BIOLOGY
(2023)