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Blum I, Wong JS, Godino Padre K, Stolzenberg J, Fuchs H, Baumann KS, Poppe B, Looe HK. Fano cavity test and investigation of the response of the Roos chamber irradiated by proton beams in perpendicular magnetic fields up to 1 T. Phys Med Biol 2024; 69:085021. [PMID: 38452383 DOI: 10.1088/1361-6560/ad311a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 03/07/2024] [Indexed: 03/09/2024]
Abstract
Objective. The aim of this work is to investigate the response of the Roos chamber (type 34001) irradiated by clinical proton beams in magnetic fields.Approach. At first, a Fano test was implemented in Monte Carlo software package GATE version 9.2 (based on Geant4 version 11.0.2) using a cylindrical slab geometry in a magnetic field up to 1 T. In accordance to an experimental setup (Fuchset al2021), the magnetic field correction factorskQB⃗of the Roos chamber were determined at different energies up to 252 MeV and magnetic field strengths up to 1 T, by separately simulating the ratios of chamber signalsMQ/MQB⃗,without and with magnetic field, and the dose-conversion factorsDw,QB⃗/Dw,Qin a small cylinder of water, with and without magnetic field. Additionally, detailed simulations were carried out to understand the observed magnetic field dependence.Main results. The Fano test was passed with deviations smaller than 0.25% between 0 and 1 T. The ratios of the chamber signals show both energy and magnetic field dependence. The maximum deviation of the dose-conversion factors from unity of 0.22% was observed at the lowest investigated proton energy of 97.4 MeV andB⃗= 1 T. The resultingkQB⃗factors increase initially with the applied magnetic field and decrease again after reaching a maximum at around 0.5 T; except for the lowest 97.4 MeV beam that show no observable magnetic field dependence. The deviation from unity of the factors is also larger for higher proton energies, where the maximum lies at 1.0035(5), 1.0054(7) and 1.0069(7) for initial energies ofE0= 152, 223.4 and 252 MeV, respectively.Significance. Detailed Monte Carlo studies showed that the observed effect can be mainly attributed to the differences in the transport of electrons produced both outside and inside of the air cavity in the presence of a magnetic field.
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Affiliation(s)
- Isabel Blum
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Jing Syuen Wong
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Krishna Godino Padre
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Jessica Stolzenberg
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Hermann Fuchs
- Division of Medical Physics, Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Kilian-Simon Baumann
- University Hospital Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
- Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Björn Poppe
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Hui Khee Looe
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
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Wulff J, Paul A, Bäcker CM, Baumann KS, Esser JN, Koska B, Timmermann B, Verbeek NG, Bäumer C. Consistency of Faraday cup and ionization chamber dosimetry of proton fields and the role of nuclear interactions. Med Phys 2024; 51:2277-2292. [PMID: 37991110 DOI: 10.1002/mp.16819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND A Faraday cup (FC) facilitates a quite clean measurement of the proton fluence emerging from clinical spot-scanning nozzles with narrow pencil-beams. The utilization of FCs appears to be an attractive option for high dose rate delivery modes and the source models of Monte-Carlo (MC) dose engines. However, previous studies revealed discrepancies of 3%-6% between reference dosimetry with ionization chambers (ICs) and FC-based dosimetry. This has prevented the widespread use of FCs for dosimetry in proton therapy. PURPOSE The current study aims at bridging the gap between FC dosimetry and IC dosimetry of proton fields delivered with spot-scanning treatment heads. Particularly, a novel method to evaluate FC measurements is introduced. METHODS A consistency check is formulated, which makes use of the energy balance and the reciprocity theorem. The measurement data comprise central-axis depth distributions of the absorbed dose of quasi-monochromatic fields with a width of about 28.5 cm and FC measurements of the reciprocal fields with a single spot. These data are complemented by a look-up of energy-range tables, the average Q-value of transmutations, and the escape energy carried away by neutrons and photons. The latter data are computed by MC simulations, which in turn are validated with measurements of the distal dose tail and neutron out-of-field doses. For comparison, the conventional approach of FC evaluation is performed, which computes absorbed dose from the product of fluence and stopping power. The results from the FC measurements are compared with the standard dosimetry protocols and improved reference dosimetry methods. RESULTS The deviation between the conventional FC-based dosimetry and the IC-based one according to standard dosimetry protocols was -4.7 ( ± $\pm$ 3.3)% for a 100 MeV field and -3.6 ( ± $\pm$ 3.5)% for 200 MeV, thereby agreeing within the reported uncertainties. The deviations could be reduced to -4.0 ( ± $\pm$ 2.9)% and -3.0 ( ± $\pm$ 3.1)% by adopting state-of-the-art reference dosimetry methods. The alternative approach using the energy balance gave deviations of only -1.9% (100 MeV) and -2.6% (200 MeV) using state-of-the-art dosimetry. The standard uncertainty of this novel approach was estimated to be about 2%. CONCLUSIONS An alternative concept has been established to determine the absorbed dose of monoenergetic proton fields with an FC. It eliminates the strong dependence of the conventional FC-based approach on the MC simulation of the stopping-power and of the secondary ions, which according to the study at hand is the major contributor to the underestimation of the absorbed dose. Some contributions to the uncertainty of the novel approach could potentially be reduced in future studies. This would allow for accurate consistency tests of conventional dosimetry procedures.
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Affiliation(s)
- Jörg Wulff
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Anne Paul
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Claus Maximilian Bäcker
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Kilian-Simon Baumann
- Department of Radiotherapy and Radiation Oncology, Marburg University Hospital, Marburg, Germany
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Johannes Niklas Esser
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Benjamin Koska
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Cancer Consortium (DKTK), Essen, Germany
- Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Nico Gerd Verbeek
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- German Cancer Consortium (DKTK), Essen, Germany
- Department of Physics, Technische Universität Dortmund, Dortmund, Germany
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Gebauer B, Baumann KS, Fuchs H, Georg D, Oborn BM, Looe HK, Lühr A. Proton dosimetry in a magnetic field: Measurement and calculation of magnetic field correction factors for a plane-parallel ionization chamber. Med Phys 2024; 51:2293-2305. [PMID: 37898105 DOI: 10.1002/mp.16797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 08/31/2023] [Accepted: 09/04/2023] [Indexed: 10/30/2023] Open
Abstract
BACKGROUND The combination of magnetic resonance imaging and proton therapy offers the potential to improve cancer treatment. The magnetic field (MF)-dependent change in the dosage of ionization chambers in magnetic resonance imaging-integrated proton therapy (MRiPT) is considered by the correction factork B ⃗ , M , Q $k_{\vec{B},M,Q}$ , which needs to be determined experimentally or computed via Monte Carlo (MC) simulations. PURPOSE In this study,k B ⃗ , M , Q $k_{\vec{B},M,Q}$ was both measured and simulated with high accuracy for a plane-parallel ionization chamber at different clinical relevant proton energies and MF strengths. MATERIAL AND METHODS The dose-response of the Advanced Markus chamber (TM34045, PTW, Freiburg, Germany) irradiated with homogeneous 10 × $\times$ 10 cm2 $^2$ quasi mono-energetic fields, using 103.3, 128.4, 153.1, 223.1, and 252.7 MeV proton beams was measured in a water phantom placed in the MF of an electromagnet with MF strengths of 0.32, 0.5, and 1 T. The detector was positioned at a depth of 2 g/cm2 $^2$ in water, with chamber electrodes parallel to the MF lines and perpendicular to the proton beam incidence direction. The measurements were compared with TOPAS MC simulations utilizing COMSOL-calculated 0.32, 0.5, and 1 T MF maps of the electromagnet.k B ⃗ , M , Q $k_{\vec{B},M,Q}$ was calculated for the measurements for all energies and MF strengths based on the equation:k B ⃗ , M , Q = M Q M Q B ⃗ $k_{\vec{B},M,Q}=\frac{M_\mathrm{Q}}{M_\mathrm{Q}^{\vec{B}}}$ , whereM Q B ⃗ $M_\mathrm{Q}^{\vec{B}}$ andM Q $M_\mathrm{Q}$ were the temperature and air-pressure corrected detector readings with and without the MF, respectively. MC-based correction factors were determined ask B ⃗ , M , Q = D det D det B ⃗ $k_{\vec{B},M,Q}=\frac{D_\mathrm{det}}{D_\mathrm{det}^{\vec{B}}}$ , whereD det B ⃗ $D_\mathrm{det}^{\vec{B}}$ andD det $D_\mathrm{det}$ were the doses deposited in the air cavity of the ionization chamber model with and without the MF, respectively. Furthermore, MF effects on the chamber dosimetry are studied using MC simulations, examining the impact on the absorbed dose-to-water (D W $D_{W}$ ) and the shift in depth of the Bragg peak. RESULTS The detector showed a reduced dose-response for all measured energies and MF strengths, resulting in experimentally determinedk B ⃗ , M , Q $k_{\vec{B},M,Q}$ values larger than unity. For all energies and MF strengths examined,k B ⃗ , M , Q $k_{\vec{B},M,Q}$ ranged between 1.0065 and 1.0205. The dependence on the energy and the MF strength was found to be non-linear with a maximum at 1 T and 252.7 MeV. The MC simulatedk B ⃗ , M , Q $k_{\vec{B},M,Q}$ values agreed with the experimentally determined correction factors within their standard deviations with a maximum difference of 0.6%. The MC calculated impact onD W $D_{W}$ was smaller 0.2 %. CONCLUSION For the first time, measurements and simulations were compared for proton dosimetry within MFs using an Advanced Markus chamber. Good agreement ofk B ⃗ , M , Q $k_{\vec{B},M,Q}$ was found between experimentally determined and MC calculated values. The performed benchmarking of the MC code allows for calculatingk B ⃗ , M , Q $k_{\vec{B},M,Q}$ for various ionization chamber models, MF strengths and proton energies to generate the data needed for a proton dosimetry protocol within MFs and is, therefore, a step towards MRiPT.
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Affiliation(s)
- Benjamin Gebauer
- OncoRay National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Institute of Radiooncology-OncoRay, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Kilian-Simon Baumann
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
- Ion-Beam Therapy Center, Marburg, Germany
| | - Hermann Fuchs
- Department of Radiation Oncology, Medical University of Vienna, Wien, Austria
- MedAustron Iontherapy centre, Wiener Neustadt, Austria
| | - Dietmar Georg
- Department of Radiation Oncology, Medical University of Vienna, Wien, Austria
- MedAustron Iontherapy centre, Wiener Neustadt, Austria
| | - Brad M Oborn
- Institute of Radiooncology-OncoRay, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia
- Illawarra Cancer Care Centre, Wollongong, New South Wales, Australia
| | - Hui-Khee Looe
- Department for Radiotherapy and Radiooncology, Pius Hospital, Medical Campus Carl von Ossietzky University, Oldenburg, Germany
| | - Armin Lühr
- Department of Physics, TU Dortmund University, Dortmund, Germany
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Derksen L, Adeberg S, Zink K, Baumann KS. Comparison of two methods simulating inter-track interactions using the radiobiological Monte Carlo toolkit TOPAS-nBio. Phys Med Biol 2024; 69:03NT01. [PMID: 38198700 DOI: 10.1088/1361-6560/ad1cf4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 01/10/2024] [Indexed: 01/12/2024]
Abstract
Objective.To compare two independently developed methods that enable modelling inter-track interactions in TOPAS-nBio by examining the yield of radiolytic species in radiobiological Monte Carlo track structure simulations. One method uses a phase space file to assign more than one primary to one event, allowing for inter-track interaction between these primary particles. This method has previously been developed by this working group and published earlier. Using the other method, chemical reactions are simulated based on a new version of the independent reaction time approach to allow inter-track interactions.Approach.G-values were calculated and compared using both methods for different numbers of tracks able to undergo inter-track interactions.Main results.Differences in theG-values simulated with the two methods strongly depend on the molecule type, and deviations can range up to 3.9% (H2O2), although, on average, the deviations are smaller than 1.5%.Significance.Both methods seem to be suitable for simulating inter-track interactions, as they provide comparableG-values even though both techniques were developed independently of each other.
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Affiliation(s)
- Larissa Derksen
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Sebastian Adeberg
- Marburg University Hospital, Department of Radiotherapy and Radiation Oncology, Marburg, Germany
- Marburg Ion-Beam Therapy Center (MIT), Department of Radiotherapy and Radiation Oncology, Marburg University Hospital, Marburg, Germany
- University Cancer Center, Frankfurt-Marburg, Germany
| | - Klemens Zink
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
- Marburg University Hospital, Department of Radiotherapy and Radiation Oncology, Marburg, Germany
- Marburg Ion-Beam Therapy Center (MIT), Department of Radiotherapy and Radiation Oncology, Marburg University Hospital, Marburg, Germany
| | - Kilian-Simon Baumann
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
- Marburg University Hospital, Department of Radiotherapy and Radiation Oncology, Marburg, Germany
- Marburg Ion-Beam Therapy Center (MIT), Department of Radiotherapy and Radiation Oncology, Marburg University Hospital, Marburg, Germany
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Baumann KS, Derksen L, Witt M, Adeberg S, Zink K. The influence of different versions of FLUKA and GEANT4 on the calculation of response functions of ionization chambers in clinical proton beams. Phys Med Biol 2023; 68:24NT01. [PMID: 37939402 DOI: 10.1088/1361-6560/ad0ad4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 11/08/2023] [Indexed: 11/10/2023]
Abstract
Objective.To investigate the influence of different versions of the Monte Carlo codesgeant4 andflukaon the calculation of overall response functionsfQof air-filled ionization chambers in clinical proton beams.Approach. fQfactors were calculated for six plane-parallel and four cylindrical ionization chambers withgeant4 andfluka. These factors were compared to already published values that were derived using older versions of these codes.Main results.Differences infQfactors calculated with different versions of the same Monte Carlo code can be up to ∼1%. Especially forgeant4, the updated version leads to a more pronounced dependence offQon proton energy and to smallerfQfactors for high energies.Significance.Different versions of the same Monte Carlo code can lead to differences in the calculation offQfactors of up to ∼1% without changing the simulation setup, transport parameters, ionization chamber geometry modeling, or employed physics lists. These findings support the statement that the dominant contributor to the overall uncertainty of Monte Carlo calculatedfQfactors are type-B uncertainties.
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Affiliation(s)
- Kilian-Simon Baumann
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
| | - Larissa Derksen
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Matthias Witt
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
| | - Sebastian Adeberg
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
- Universitäres Centrum für Tumorerkrankungen (UCT) Frankfurt - Marburg, Germany
| | - Klemens Zink
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
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Baumann KS, Gomà C, Wulff J, Kretschmer J, Zink K. Monte Carlo calculated ionization chamber correction factors in clinical proton beams - deriving uncertainties from published data. Phys Med 2023; 113:102655. [PMID: 37603909 DOI: 10.1016/j.ejmp.2023.102655] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 06/16/2023] [Accepted: 08/05/2023] [Indexed: 08/23/2023] Open
Abstract
For the update of the IAEA TRS-398 Code of Practice (CoP), global ionization chamber factors (fQ) and beam quality correction factors (kQ) for air-filled ionization chambers in clinical proton beams have been calculated with different Monte Carlo codes. In this study, average Monte Carlo calculated fQ and kQ factors are provided and the uncertainty of these factors is estimated. Average fQ factors in monoenergetic proton beams with energies between 60 MeV and 250 MeV were derived from Monte Carlo calculated fQ factors published in the literature. Altogether, 195 fQ factors for six plane-parallel and three cylindrical ionization chambers calculated with penh, fluka and geant4 were incorporated. Additionally, a weighted standard deviation of fQ factors was calculated, where the same weight was assigned to each Monte Carlo code. From average fQ factors, kQ factors were derived and compared to the values from the IAEA TRS-398 CoP published in 2000 as well as to the values of the upcoming version. Average Monte Carlo calculated fQ factors are constant within 0.6% over the energy range investigated. In general, the different Monte Carlo codes agree within 1% for low energies and show larger differences up to 2% for high energies. As a result, the standard deviation of fQ factors increases with energy and is ∼0.3% for low energies and ∼0.8% for high energies. kQ factors derived from average Monte Carlo calculated fQ factors differ from the values presented in the IAEA TRS-398 CoP by up to 2.4%. The overall estimated uncertainty of Monte Carlo calculated kQ factors is ∼0.5%-1% smaller than the uncertainties estimated in IAEA TRS-398 CoP since the individual ionization chamber characteristics (e.g. fluence perturbations) are considered in detail in Monte Carlo calculations. The agreement between Monte Carlo calculated kQ factors and the values of the upcoming version of IAEA TRS-398 CoP is better with deviations smaller than 1%.
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Affiliation(s)
- Kilian-Simon Baumann
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany; University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany; Marburg Ion-Beam Therapy Center, Marburg, Germany.
| | - Carles Gomà
- Hospital Clínic de Barcelona, Department of Radiation Oncology, Barcelona, Spain
| | - Jörg Wulff
- West German Proton Therapy Center (WPE), Essen, Germany
| | - Jana Kretschmer
- Carl-von-Ossietzky University, University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Oldenburg, Germany; Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Klemens Zink
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany; University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany; Marburg Ion-Beam Therapy Center, Marburg, Germany
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Derksen L, Flatten V, Engenhart-Cabillic R, Zink K, Baumann KS. A method to implement inter-track interactions in Monte Carlo simulations with TOPAS-nBio and their influence on simulated radical yields following water radiolysis. Phys Med Biol 2023. [PMID: 37285861 DOI: 10.1088/1361-6560/acdc7d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
OBJECTIVE In FLASH radiotherapy (dose rates ≥ 40 Gy/s), a reduced normal tissue toxicity has been observed, while maintaining the same tumor control compared to conventional radiotherapy (dose rates ≤ 0.03 Gy/s). This protecting effect could not be fully explained yet. One assumption is that interactions between the chemicals of different primary ionizing particles, so-called inter-track interactions, trigger this outcome. In this work, we included inter-track interactions in Monte Carlo track structure simulations and investigated the yield of chemicals (G-value) produced by ionizing particles. 
Approach: For the simulations, we used the Monte Carlo toolkit TOPAS, in which inter-track interactions cannot be implemented without further effort. Thus, we developed a method enabling the simultaneous simulation of N original histories in one event allowing chemical species to interact with each other. To investigate the effect of inter-track interactions we analyzed the G-value of different chemicals using various radiation sources. We used electrons with an energy of 60 eV in different spatial arrangements as well as a 10 MeV and 100 MeV proton source. For electrons we set N between 1 and 60, for protons between 1 and 100.
Main results: In all simulations, the total G-value decreases with increasing N. In detail, the G-value for●OH, H3O and eaqdecreases with increasing N, whereas the G-value of OH-, H2O2and H2increases slightly. The reason is that with increasing N, the concentration of chemical radicals increases allowing for more chemical reactions between the radicals resulting in a change of the dynamics of the chemical stage.
Signifcance: Inter-track interactions resulting in a variation of the yield of chemical species, may be a factor explaining the FLASH effect. To verify this hypothesis, further simulations are necessary in order to evaluate the impact of varying G-values on the yield of DNA damages.
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Affiliation(s)
- Larissa Derksen
- , University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Wiesenstraße 14, Giessen, 35390, GERMANY
| | - Veronika Flatten
- Klinik für Strahlentherapie, Universitätsklinikum Gießen und Marburg - Standort Marburg, Baldingerstraße, Marburg, 35043, GERMANY
| | - Rita Engenhart-Cabillic
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Baldingerstraße, Marburg, 35043, GERMANY
| | - Klemens Zink
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Baldingerstraße, Marburg, 35043, GERMANY
| | - Kilian-Simon Baumann
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Baldingerstraße, Marburg, 35043, GERMANY
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Eberle F, Engenhart-Cabillic R, Schymalla MM, Dumke C, Schötz U, Subtil FSB, Baumann KS, Stuck BA, Langer C, Jensen AD, Hauswald H, Lautenschläger S. Carbon Ion Beam Boost Irradiation in Malignant Tumors of the Nasal Vestibule and the Anterior Nasal Cavity as an Organ-Preserving Therapy. Front Oncol 2022; 12:814082. [PMID: 35242709 PMCID: PMC8886023 DOI: 10.3389/fonc.2022.814082] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/19/2022] [Indexed: 11/20/2022] Open
Abstract
Background Surgery and radiotherapy are current therapeutic options for malignant tumors involving the nasal vestibule. Depending on the location, organ-preserving resection is not always possible, even for small tumors. Definitive radiotherapy is an alternative as an organ-preserving procedure. Carbon ion beam radiotherapy offers highly conformal dose distributions and more complex biological radiation effects eventually resulting in optimized normal tissue sparing and improved outcome. The aim of the current study was to analyze toxicity, local control (LC), and organ preserving survival (OPS) after irradiation of carcinoma of the nasal vestibule with raster-scanned carbon ion radiotherapy boost (CIRT-B) combined with volumetric intensity modulated arc therapy (VMAT) with photons. Methods Between 12/2015 and 05/2021, 21 patients with malignant tumors involving the nasal vestibule were irradiated with CIRT-B combined with VMAT and retrospectively analyzed. Diagnosis was based on histologic findings. A total of 17 patients had squamous cell carcinoma (SCC) and 4 had other histologies. In this series, 10%, 67%, and 24% of patients had Wang stages 1, 2, and 3 tumors, respectively. Three patients had pathologic cervical nodes on MRI. The median CIRT-B dose was 24 Gy(RBE), while the median VMAT dose was 50 Gy. All patients with pathologic cervical nodes received simultaneously integrated boost with photons (SIB) up to a median dose of 62.5 Gy to the pathological lymph nodes. Eight patients received cisplatin chemotherapy. All patients received regular follow-up imaging after irradiation. Kaplan–Meier estimation was used for statistical assessment. Results The median follow-up after irradiation was 18.9 months. There were no common toxicity criteria grade 5 or 4 adverse events. A total of 20 patients showed grade 3 adverse events mainly on skin and mucosa. All patients were alive at the end of follow-up. The median OPS after treatment was 56.5 months. The 6- and 24-month OPS were 100% and 83.3%, respectively. All local recurrences occurred within 12 months after radiotherapy. The median progression free survival (PFS) after treatment was 52.4 months. The 6-, 12-, and 24-month PFS rates were 95%, 83.6%, and 74.3%, respectively. Conclusion CIRT-B combined with VMAT in malignant tumors of the nasal vestibule is safe and feasible, results in high local control rates, and thus is a good option as organ-preserving therapy. No radiation-associated grade 4 or 5 acute or late AE was documented.
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Affiliation(s)
- Fabian Eberle
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany
| | - Rita Engenhart-Cabillic
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany
| | - Markus M Schymalla
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany
| | - Christoph Dumke
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany
| | - Ulrike Schötz
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany
| | - Florentine S B Subtil
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany
| | - Kilian-Simon Baumann
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany
| | - Boris A Stuck
- Department of Otolaryngology/Head & Neck Surgery, Marburg University Hospital, Marburg, Germany
| | - Christine Langer
- Department of Otolaryngology/Head & Neck Surgery, Gießen University Hospital, Gießen, Germany
| | - Alexandra D Jensen
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Department of Radiation Oncology, Gießen University Hospital, Gießen, Germany
| | - Henrik Hauswald
- Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stefan Lautenschläger
- Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Department of Radiation Oncology, Marburg University Hospital, Marburg, Germany
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Burg JM, Flatten V, Witt M, Derksen L, Weber U, Engenhart-Cabillic R, Vorwerk H, Zink K, Baumann KS. Experimental determination of modulation power of lung tissue for particle therapy. Phys Med Biol 2021; 66. [PMID: 34844221 DOI: 10.1088/1361-6560/ac3e0d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 11/29/2021] [Indexed: 12/25/2022]
Abstract
In particle therapy of lung tumors, modulating effects on the particle beam may occur due to the microscopic structure of the lung tissue. These effects are caused by the heterogeneous nature of the lung tissue and cannot be completely taken into account during treatment planning, because these micro structures are too small to be fully resolved in the planning CT. In several publications, a new material parameter called modulation power (Pmod) was introduced to characterize the effect. For various artificial lung surrogates, this parameter was measured and published by other groups and ranges up to approximately 1000μm. Studies investigating the influence of the modulation power on the dose distribution during irradiation are using this parameter in the rang of 100-800μm. More precise measurements forPmodon real lung tissue have not yet been published. In this work, the modulation power of real lung tissue was measured using porcine lungs in order to produce more reliable data ofPmodfor real lung tissue. For this purpose,ex-vivoporcine lungs were frozen in a ventilated state and measurements in a carbon ion-beam were performed. Due to the way the lungs were prepared and transferred to a solid state, the lung structures that modulate the beam could also be examined in detail using micro CT imaging. An optimization of the established methods of measuring the modulation power, which takes better account of the typical structures within lung tissue, was developed as well.
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Affiliation(s)
- Jan Michael Burg
- University of Applied Sciences Giessen, Institute of Medical Physics and Radiation Protection, Germany.,University Medical Center Giessen and Marburg, Department of Radiotherapy and Radiation Oncology, Germany
| | - Veronika Flatten
- University of Applied Sciences Giessen, Institute of Medical Physics and Radiation Protection, Germany.,University Medical Center Giessen and Marburg, Department of Radiotherapy and Radiation Oncology, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Matthias Witt
- University of Applied Sciences Giessen, Institute of Medical Physics and Radiation Protection, Germany.,University Medical Center Giessen and Marburg, Department of Radiotherapy and Radiation Oncology, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Larissa Derksen
- University of Applied Sciences Giessen, Institute of Medical Physics and Radiation Protection, Germany
| | - Uli Weber
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Darmstadt, Germany
| | - Rita Engenhart-Cabillic
- University Medical Center Giessen and Marburg, Department of Radiotherapy and Radiation Oncology, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Hilke Vorwerk
- University Medical Center Giessen and Marburg, Department of Radiotherapy and Radiation Oncology, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Klemens Zink
- University of Applied Sciences Giessen, Institute of Medical Physics and Radiation Protection, Germany.,University Medical Center Giessen and Marburg, Department of Radiotherapy and Radiation Oncology, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Kilian-Simon Baumann
- University of Applied Sciences Giessen, Institute of Medical Physics and Radiation Protection, Germany.,University Medical Center Giessen and Marburg, Department of Radiotherapy and Radiation Oncology, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
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Paz AES, Baumann KS, Weber UA, Witt M, Zink K, Durante M, Graeff C. Compensating for beam modulation due to microscopic lung heterogeneities in carbon ion therapy treatment planning. Med Phys 2021; 48:8052-8061. [PMID: 34668589 DOI: 10.1002/mp.15292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 08/17/2021] [Accepted: 09/26/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To predict and mitigate for the degradation in physical and biologically effective dose distributions of particle beams caused by microscopic heterogeneities in lung tissue. MATERIALS AND METHODS The TRiP98 treatment planning system was adapted to account for the beam-modulating effect of heterogeneous lung tissue in physical and biological inverse treatment planning. The implementation employs an analytical model that derives the degradation from the established "modulation power" parameter P mod and the total water-equivalent thickness of lung parenchyma traversed by the beam. Beam modulation was reproduced through an on-the-fly convolution of the reference Bragg curve with Gaussian kernels depending on the modulation power of lung tissue (upstream). For biological doses, the degradation was determined by modulating dose-averaged α , β , and LET distributions. Carbon SOBP measurements behind lung substitute material were performed to validate the code. The implementation was then applied to a phantom and patient case. RESULTS Experimental results show the passage through a 20-cm Gammex LN300 slab led to a decrease in target coverage and broadening of the SOBP distal fall-off. However, dose coverage was regained through optimization. A good agreement between calculated and measured SOBPs was also found. In addition, a patient case study revealed a 3.2% decrease in D 95 from degradation ( P mod = 450 μ m), which was reduced to a 0.4% difference after optimization. Furthermore, widening of the RBE distribution beyond the target distal edge was observed. This implies an increased degradation in the biological dose, which could be harmful to healthy tissues distal to the target. CONCLUSIONS This is the first implementation capable of compensating for lung dose perturbations, which is more effective than margin extensions. A larger patient study is needed to examine the observed modulation in the RBE distribution and judge the clinical relevance also in IMPT, where margins might prove insufficient to recover target coverage.
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Affiliation(s)
| | - Kilian-Simon Baumann
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany.,Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany
| | - Uli Andreas Weber
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - Matthias Witt
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
| | - Klemens Zink
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany.,Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany
| | - Marco Durante
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany.,Institute for Condensed Matter Physics (CG), Technical University, Darmstadt, Germany
| | - Christian Graeff
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany.,Department of Electrical Engineering and Information Technology, Technical University, Darmstadt, Germany
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11
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Derksen L, Pfuhl T, Engenhart-Cabillic R, Zink K, Baumann KS. Investigating the feasibility of TOPAS-nBio for Monte Carlo track structure simulations by adapting GEANT4-DNA examples application. Phys Med Biol 2021; 66. [PMID: 34384060 DOI: 10.1088/1361-6560/ac1d21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/12/2021] [Indexed: 11/12/2022]
Abstract
Purpose.The purpose of this work is to investigate the feasibility of TOPAS-nBio for track structure simulations using tuple scoring and ROOT/Python-based post-processing.Materials and methods.There are several example applications implemented in GEANT4-DNA demonstrating track structure simulations. These examples are not implemented by default in TOPAS-nBio. In this study, the tuple scorer was used to re-simulate these examples. The simulations contained investigations of different physics lists, calculation of energy-dependent range, stopping power, mean free path andW-value. Additionally, further applications of the TOPAS-nBio tool were investigated, focusing on physical interactions and deposited energies of electrons with initial energies in the range of 10-60 eV, not covered in the recently published GEANT4-DNA simulations. Low-energetic electrons are currently of great interest in the radiobiology research community due to their high effectiveness towards the induction of biological damage.Results.The quantities calculated with TOPAS-nBio show a good agreement with the simulations of GEANT4-DNA with deviations of 5% at maximum. Thus, we have presented a feasible way to implement the example applications included in GEANT4-DNA in TOPAS-nBio. With the extended simulations, an insight could be given, which further tracking information can be gained with the track structure code and how cross sections and physics models influence a particle's fate.Conclusion.With our results, we could show the potentials of applying the tuple scorer in TOPAS-nBio Monte Carlo track structure simulations. Using this scorer, a large amount of information about the track structure can be accessed, which can be analyzed as preferred after the simulation.
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Affiliation(s)
- Larissa Derksen
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Tabea Pfuhl
- GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - Rita Engenhart-Cabillic
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
| | - Klemens Zink
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany.,University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
| | - Kilian-Simon Baumann
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany.,University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
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Baumann KS, Derksen L, Witt M, Michael Burg J, Engenhart-Cabillic R, Zink K. Monte Carlo calculation of beam quality correction factors in proton beams using FLUKA. Phys Med Biol 2021; 66. [PMID: 34378546 DOI: 10.1088/1361-6560/ac1c4b] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 08/10/2021] [Indexed: 11/12/2022]
Abstract
Purpose.To provide Monte Carlo calculated beam quality correction factors (kQ) for monoenergetic proton beams using the Monte Carlo codefluka.Materials and methods.The Monte Carlo codeflukawas used to calculate the dose absorbed in a water-filled reference volume and the air-filled cavities of six plane-parallel and four cylindrical ionization chambers. The chambers were positioned at the entrance region of monoenergetic proton beams with energies between 60 and 250 MeV. Based on these dose values,fQas well askQfactors were calculated whilefQ0factors were taken from Andreoet al(2020Phys. Med. Biol.65095011).Results. kQfactors calculated in this work were found to agree with experimentally determinedkQfactors on the 1%-level, with only two exceptions with deviations of 1.4% and 1.9%. The comparison offQfactors calculated usingflukawithfQfactors calculated using the Monte Carlo codesgeant4 andpenhshowed a general good agreement for low energies, while differences for higher energies were pronounced. For high energies, in most cases the Monte Carlo codesflukaandgeant4 lead to comparable results while thefQfactors calculated withpenhare larger.Conclusion.flukacan be used to calculatekQfactors in clinical proton beams. The divergence of Monte Carlo calculatedkQfactors for high energies suggests that the role of nuclear interaction models implemented in the different Monte Carlo codes needs to be investigated in more detail.
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Affiliation(s)
- Kilian-Simon Baumann
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Larissa Derksen
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Matthias Witt
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Jan Michael Burg
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Rita Engenhart-Cabillic
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
| | - Klemens Zink
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany.,Marburg Ion-Beam Therapy Center, Marburg, Germany
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Flatten V, Burg JM, Witt M, Derksen L, Fragoso Costa P, Wulff J, Bäumer C, Timmermann B, Weber U, Vorwerk H, Engenhart-Cabillic R, Zink K, Baumann KS. Estimating the modulating effect of lung tissue in particle therapy using a clinical CT voxel histogram analysis. Phys Med Biol 2021; 66. [PMID: 34298533 DOI: 10.1088/1361-6560/ac176e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/23/2021] [Indexed: 11/12/2022]
Abstract
To treat lung tumours with particle therapy, different additional tasks and challenges in treatment planning and application have to be addressed thoroughly. One of these tasks is the quantification and consideration of the Bragg peak degradation due to lung tissue: As lung is an heterogeneous tissue, the Bragg peak is broadened when particles traverse the microscopic alveoli. These are not fully resolved in clinical CT images and thus, the effect is not considered in the dose calculation. In this work, a correlation between the CT histograms of heterogeneous material and the impact on the Bragg peak curve is presented. Different inorganic materials were scanned with a conventional CT scanner and additionally, the Bragg peak degradation was measured in a proton beam and was then quantified. A model is proposed that allows an estimation of the modulation power by performing a histogram analysis on the CT scan. To validate the model for organic samples, a second measurement series was performed with frozen porcine lunge samples. This allows to investigate the possible limits of the proposed model in a set-up closer to clinical conditions. For lung substitutes, the agreement between model and measurement is within ±0.05 mm and for the organic lung samples, within ±0.15 mm. This work presents a novel, simple and efficient method to estimate if and how much a material or a distinct region (within the lung) is degrading the Bragg peak on the basis of a common clinical CT image. Up until now, only a direct in-beam measurement of the region or material of interest could answer this question.
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Affiliation(s)
- Veronika Flatten
- Department of Radiotherapy and Radiooncology, University Hospital of Giessen and Marburg Campus Marburg, Marburg, GERMANY
| | - Jan Michael Burg
- , University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, GERMANY
| | - Matthias Witt
- Department of Radiotherapy and Radiooncology, University Hospital of Giessen and Marburg Campus Marburg, Marburg, GERMANY
| | - Larissa Derksen
- , University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, GERMANY
| | | | - Jörg Wulff
- Medical Physics, Westdeutsches Protonentherapiezentrum Essen gGmbH, Essen, GERMANY
| | | | - Beate Timmermann
- Deparment of Particle Therapy, University Hospital Essen, Essen, GERMANY
| | - Uli Weber
- , GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt, Hessen, GERMANY
| | - Hilke Vorwerk
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, GERMANY
| | - Rita Engenhart-Cabillic
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, GERMANY
| | - Klemens Zink
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, GERMANY
| | - Kilian-Simon Baumann
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, GERMANY
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Baumann KS, Kaupa S, Bach C, Engenhart-Cabillic R, Zink K. Monte Carlo calculation of perturbation correction factors for air-filled ionization chambers in clinical proton beams using TOPAS/GEANT. Z Med Phys 2021; 31:175-191. [PMID: 33775521 DOI: 10.1016/j.zemedi.2020.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 08/20/2020] [Accepted: 08/31/2020] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Current dosimetry protocols for clinical protons using air-filled ionization chambers assume that the perturbation correction factor is equal to unity for all ionization chambers and proton energies. Since previous Monte Carlo based studies suggest that perturbation correction factors might be significantly different from unity this study aims to determine perturbation correction factors for six plane-parallel and four cylindrical ionization chambers in proton beams at clinical energies. MATERIALS AND METHODS The dose deposited in the air cavity of the ionization chambers was calculated with the help of the Monte Carlo code TOPAS/Geant4 while specific constructive details of the chambers were removed step by step. By comparing these dose values the individual perturbation correction factors pcel, pstem, psleeve, pwall, pcav⋅pdis as well as the total perturbation correction factor pQ were derived for typical clinical proton energies between 80 and 250MeV. RESULTS The total perturbation correction factor pQ was smaller than unity for almost every ionization chamber and proton energy and in some cases significantly different from unity (deviation larger than 1%). The maximum deviation from unity was 2.0% for cylindrical and 1.5% for plane-parallel ionization chambers. Especially the factor pwall was found to differ significantly from unity. It was shown that this is due to the fact that secondary particles, especially alpha particles and fragments, are scattered from the chamber wall into the air cavity resulting in an overresponse of the chamber. CONCLUSION Perturbation correction factors for ionization chambers in proton beams were calculated using Monte Carlo simulations. In contrast to the assumption of current dosimetry protocols the total perturbation correction factor pQ can be significantly different from unity. Hence, beam quality correction factors [Formula: see text] that are calculated with the help of perturbation correction factors that are assumed to be unity come with a corresponding additional uncertainty.
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Affiliation(s)
- Kilian-Simon Baumann
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany; University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany; Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany.
| | - Sina Kaupa
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Constantin Bach
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Rita Engenhart-Cabillic
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany; Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
| | - Klemens Zink
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany; University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany; Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany; Frankfurt Institute of Advanced Studies - FIAS, Frankfurt, Germany
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15
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Baumann KS, Flatten V, Weber U, Lautenschläger S, Eberle F, Zink K, Engenhart-Cabillic R. Correction to: Effects of the Bragg peak degradation due to lung tissue in proton therapy of lung cancer patients. Radiat Oncol 2020; 15:29. [PMID: 32014028 PMCID: PMC6996163 DOI: 10.1186/s13014-020-1475-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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16
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Baumann KS, Kaupa S, Bach C, Engenhart-Cabillic R, Zink K. Corrigendum: Monte Carlo calculation of beam quality correction factors in proton beams using TOPAS/GEANT4 (2020 Phys. Med. Biol. 65 055015). Phys Med Biol 2020. [DOI: 10.1088/1361-6560/ab8fc2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Baumann KS, Kaupa S, Bach C, Engenhart-Cabillic R, Zink K. Monte Carlo calculation of beam quality correction factors in proton beams using TOPAS/GEANT4. ACTA ACUST UNITED AC 2020; 65:055015. [DOI: 10.1088/1361-6560/ab6e53] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Baumann KS, Flatten V, Weber U, Lautenschläger S, Eberle F, Zink K, Engenhart-Cabillic R. Effects of the Bragg peak degradation due to lung tissue in proton therapy of lung cancer patients. Radiat Oncol 2019; 14:183. [PMID: 31653229 PMCID: PMC6814996 DOI: 10.1186/s13014-019-1375-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 09/06/2019] [Indexed: 12/25/2022] Open
Abstract
Purpose To quantify the effects of the Bragg peak degradation due to lung tissue on treatment plans of lung cancer patients with spot scanning proton therapy and to give a conservative approximation of these effects. Methods and materials Treatment plans of five lung cancer patients (tumors of sizes 2.7–46.4 cm3 at different depths in the lung) were optimized without consideration of the Bragg peak degradation. These treatment plans were recalculated with the Monte Carlo code TOPAS in two scenarios: in a first scenario, the treatment plans were calculated without including the Bragg peak degradation to reproduce the dose distribution predicted by the treatment-planning system (TPS). In a second scenario, the treatment plans were calculated while including the Bragg peak degradation. Subsequently, the plans were compared by means of Dmean, D98% and D2% in the clinical target volume (CTV) and organs at risk (OAR). Furthermore, isodose lines were investigated and a gamma index analysis was performed. Results The Bragg peak degradation leads to a lower dose in the CTV and higher doses in OARs distal to the CTV compared to the prediction from the TPS. The reduction of the mean dose in the CTV was − 5% at maximum and − 2% on average. The deeper a tumor was located in the lung and the smaller its volume the bigger was the effect on the CTV. The enhancement of the mean dose in OARs distal to the CTV was negligible for the cases investigated. Conclusions Effects of the Bragg peak degradation due to lung tissue were investigated for lung cancer treatment plans in proton therapy. This study confirms that these effects are clinically tolerable to a certain degree in the current clinical context considering the various more critical dose uncertainties due to motion and range uncertainties in proton therapy.
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Affiliation(s)
- Kilian-Simon Baumann
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany. .,University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany.
| | - Veronika Flatten
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Uli Weber
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Division, Darmstadt, Germany
| | - Stefan Lautenschläger
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
| | - Fabian Eberle
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
| | - Klemens Zink
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany.,Frankfurt Institute of Advanced Studies - FIAS, Frankfurt, Germany
| | - Rita Engenhart-Cabillic
- University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg, Germany.,Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
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Baumann KS, Horst F, Zink K, Gomà C. Comparison of penh, fluka, and Geant4/topas for absorbed dose calculations in air cavities representing ionization chambers in high-energy photon and proton beams. Med Phys 2019; 46:4639-4653. [PMID: 31350915 PMCID: PMC6851981 DOI: 10.1002/mp.13737] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 07/01/2019] [Accepted: 07/16/2019] [Indexed: 12/16/2022] Open
Abstract
Purpose The purpose of this work is to analyze whether the Monte Carlo codes penh, fluka, and geant4/topas are suitable to calculate absorbed doses and fQ/fQ0 ratios in therapeutic high‐energy photon and proton beams. Methods We used penh, fluka, geant4/topas, and egsnrc to calculate the absorbed dose to water in a reference water cavity and the absorbed dose to air in two air cavities representative of a plane‐parallel and a cylindrical ionization chamber in a 1.25 MeV photon beam and a 150 MeV proton beam — egsnrc was only used for the photon beam calculations. The physics and transport settings in each code were adjusted to simulate the particle transport as detailed as reasonably possible. From these absorbed doses, fQ0 factors, fQ factors, and fQ/fQ0 ratios (which are the basis of Monte Carlo calculated beam quality correction factors kQ,Q0) were calculated and compared between the codes. Additionally, we calculated the spectra of primary particles and secondary electrons in the reference water cavity, as well as the integrated depth–dose curve of 150 MeV protons in water. Results The absorbed doses agreed within 1.4% or better between the individual codes for both the photon and proton simulations. The fQ0 and fQ factors agreed within 0.5% or better for the individual codes for both beam qualities. The resulting fQ/fQ0 ratios for 150 MeV protons agreed within 0.7% or better. For the 1.25 MeV photon beam, the spectra of photons and secondary electrons agreed almost perfectly. For the 150 MeV proton simulation, we observed differences in the spectra of secondary protons whereas the spectra of primary protons and low‐energy delta electrons also agreed almost perfectly. The first 2 mm of the entrance channel of the 150 MeV proton Bragg curve agreed almost perfectly while for greater depths, the differences in the integrated dose were up to 1.5%. Conclusion penh, fluka, and geant4/topas are capable of calculating beam quality correction factors in proton beams. The differences in the fQ0 and fQ factors between the codes are 0.5% at maximum. The differences in the fQ/fQ0 ratios are 0.7% at maximum.
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Affiliation(s)
- Kilian-Simon Baumann
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany.,Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany
| | - Felix Horst
- Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany.,GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - Klemens Zink
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany.,Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany.,Frankfurt Institute for Advanced Studies (FIAS), Frankfurt, Germany
| | - Carles Gomà
- Department of Oncology, Laboratory of Experimental Radiotherapy, KU Leuven, Leuven, Belgium
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Flatten V, Baumann KS, Weber U, Engenhart-Cabillic R, Zink K. Quantification of the dependencies of the Bragg peak degradation due to lung tissue in proton therapy on a CT-based lung tumor phantom. Phys Med Biol 2019; 64:155005. [PMID: 31151126 DOI: 10.1088/1361-6560/ab2611] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The fine, sub-millimeter sized structure of lung tissue causes a degradation of the Bragg peak curve in particle therapy. The Bragg peak is degraded because particles of the same energy traverse lung tissue of different compositions of high and low density materials. Hence, they experience different energy losses resulting in variable ranges and a broadened Bragg peak. Since this fine structure of lung tissue is not resolved in standard treatment-planning CTs, current state-of-the-art dose calculation procedures used in the clinical routine are unable to account for this degradation. Neglecting this Bragg peak degradation in treatment planning can lead to an underdose in the target volume and an overdose distal to the target. Aim of this work is to systematically investigate the potential effects of the Bragg peak degradation on the dose distribution in dependence of different parameters like the tumor volume and its depth in lung. Proton plans were optimized on CT based phantoms without considering the Bragg peak degradation and afterwards recalculated with the Monte Carlo toolkit TOPAS: first, without consideration of the degradation and second, with the Bragg peak degradation accounted for. The direct comparison of these two dose distributions enables a quantification of the degradation effect. To carve out the dependencies of various parameters that could influence the Bragg peak degradation and thus the target dose, the simulations were performed for a variety of tumor sizes and shapes, as well as different positions within the lung. The results show that due to the Bragg peak degradation the mean dose in the target volume can be reduced by a few percent up to 14% (for extreme cases) depending on the geometry. It was shown that this effect increases with a decreasing tumor volume and increasing depth of the tumor. For the first time, a tumor specific estimation of the effect on the dose distribution due to the Bragg peak degradation in lung tissue is presented.
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Affiliation(s)
- Veronika Flatten
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany. Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany. Author to whom any correspondence should be addressed
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Wulff J, Baumann KS, Verbeek N, Bäumer C, Timmermann B, Zink K. Corrigendum: TOPAS/Geant4 configuration for ionization chamber calculations in proton beams (2018 Phys. Med. Biol. 63 115013). Phys Med Biol 2019. [DOI: 10.1088/1361-6560/ab0292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Wulff J, Baumann KS, Verbeek N, Bäumer C, Timmermann B, Zink K. TOPAS/Geant4 configuration for ionization chamber calculations in proton beams. ACTA ACUST UNITED AC 2018; 63:115013. [DOI: 10.1088/1361-6560/aac30e] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Baumann KS, Witt M, Weber U, Engenhart-Cabillic R, Zink K. An efficient method to predict and include Bragg curve degradation due to lung-equivalent materials in Monte Carlo codes by applying a density modulation. Phys Med Biol 2017; 62:3997-4016. [DOI: 10.1088/1361-6560/aa641f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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