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Metzner M, Zhevachevska D, Schlechter A, Kehrein F, Schlecker J, Murillo C, Brons S, Jäkel O, Martišíková M, Gehrke T. Energy painting: helium-beam radiography with thin detectors and multiple beam energies. Phys Med Biol 2024; 69:055002. [PMID: 38295403 DOI: 10.1088/1361-6560/ad247e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/31/2024] [Indexed: 02/02/2024]
Abstract
Objective.Compact ion imaging systems based on thin detectors are a promising prospect for the clinical environment since they are easily integrated into the clinical workflow. Their measurement principle is based on energy deposition instead of the conventionally measured residual energy or range. Therefore, thin detectors are limited in the water-equivalent thickness range they can image with high precision. This article presents ourenergy paintingmethod, which has been developed to render high precision imaging with thin detectors feasible even for objects with larger, clinically relevant water-equivalent thickness (WET) ranges.Approach.A detection system exclusively based on pixelated silicon Timepix detectors was used at the Heidelberg ion-beam therapy center to track single helium ions and measure their energy deposition behind the imaged object. Calibration curves were established for five initial beam energies to relate the measured energy deposition to WET. They were evaluated regarding their accuracy, precision and temporal stability. Furthermore, a 60 mm × 12 mm region of a wedge phantom was imaged quantitatively exploiting the calibrated energies and five different mono-energetic images. These mono-energetic images were combined in a pixel-by-pixel manner by averaging the WET-data weighted according to their single-ion WET precision (SIWP) and the number of contributing ions.Main result.A quantitative helium-beam radiograph of the wedge phantom with an average SIWP of 1.82(5) % over the entire WET interval from 150 mm to 220 mm was obtained. Compared to the previously used methodology, the SIWP improved by a factor of 2.49 ± 0.16. The relative stopping power value of the wedge derived from the energy-painted image matches the result from range pullback measurements with a relative deviation of only 0.4 %.Significance.The proposed method overcomes the insufficient precision for wide WET ranges when employing detection systems with thin detectors. Applying this method is an important prerequisite for imaging of patients. Hence, it advances detection systems based on energy deposition measurements towards clinical implementation.
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Affiliation(s)
- Margareta Metzner
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Research in Radiation Oncology (NCRO), Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiation Oncology, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Daria Zhevachevska
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Research in Radiation Oncology (NCRO), Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiation Oncology, Germany
- Heidelberg University, Medical Faculty Mannheim, Heidelberg, Germany
| | - Annika Schlechter
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Research in Radiation Oncology (NCRO), Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiation Oncology, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Florian Kehrein
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Research in Radiation Oncology (NCRO), Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiation Oncology, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Julian Schlecker
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Research in Radiation Oncology (NCRO), Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Radiooncology/Radiobiology, Germany
| | - Carlos Murillo
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiology, Germany
| | - Stephan Brons
- Heidelberg Ion-Beam Therapy Center (HIT), Radiation Oncology - Heidelberg University Hospital, Heidelberg, Germany
| | - Oliver Jäkel
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Research in Radiation Oncology (NCRO), Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiation Oncology, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), Radiation Oncology - Heidelberg University Hospital, Heidelberg, Germany
| | - Mária Martišíková
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Research in Radiation Oncology (NCRO), Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiation Oncology, Germany
| | - Tim Gehrke
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Research in Radiation Oncology (NCRO), Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiation Oncology, Germany
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
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Simeonov Y, Weber U, Schuy C, Engenhart-Cabillic R, Penchev P, Flatten V, Zink K. Development, Monte Carlo simulations and experimental evaluation of a 3D range-modulator for a complex target in scanned proton therapy. Biomed Phys Eng Express 2022; 8. [PMID: 35226887 DOI: 10.1088/2057-1976/ac5937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 02/28/2022] [Indexed: 01/02/2023]
Abstract
The purpose of this work was to develop and manufacture a 3D range-modulator (3D RM) for a complex target contour for scanned proton therapy. The 3D RM is considered to be a viable technique for the very fast dose application in patient-specific tumors with only one fixed energy. The RM was developed based on a tumor from a patient CT and manufactured with high-quality 3D printing techniques with both polymer resin and aluminum. Monte Carlo simulations were utilized to investigate its modulating properties and the resulting dose distribution. Additionally, the simulation results were validated with measurements at the Marburg Ion-Beam Therapy Centre. For this purpose, a previously developed water phantom was used to conduct fast, automated high-resolution dose measurements. The results show a very good agreement between simulations and measurements and indicate that highly homogeneous dose distributions are possible. The delivered dose is conformed to the distal as well as to the proximal edge of the target. The 3D range-modulator concept combines a high degree of dose homogeneity and conformity, comparable to standard IMPT with very short irradiation times, promising clinically applicable dose distributions for lung and/or FLASH treatment, comparable and competitive to those from conventional irradiation techniques.
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Affiliation(s)
- Yuri Simeonov
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection (IMPS), Giessen, Germany.,Philipps-University, Marburg, Germany
| | - Uli Weber
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Biophysics division, Darmstadt, Germany
| | - Christoph Schuy
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Biophysics division, 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
| | - Petar Penchev
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection (IMPS), Giessen, Germany.,Philipps-University, Marburg, Germany
| | - Veronika Flatten
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection (IMPS), Giessen, Germany.,Philipps-University, Marburg, Germany.,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 (IMPS), 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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Holm KM, Jäkel O, Krauss A. Direct determination of k
Q
for Farmer-type ionization chambers in a clinical scanned carbon-ion beam using water calorimetry. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac4fa0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/27/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Within two studies, k
Q
factors for two Farmer-type ionization chambers have been experimentally determined by means of water calorimetry in the entrance channel (EC) of a monoenergetic carbon-ion beam (Osinga-Blättermann et al 2017 Phys. Med. Biol.
62 2033–54) and for a passively modulated spread-out Bragg peak (SOBP) (Holm et al 2021 Phys. Med. Biol.
66 145012). Both studies were performed at the Heidelberg Ion Beam Therapy Center (HIT) using the PTB portable water calorimeter but applying different initial beam energies of 429 MeV u−1 for the EC and 278 MeV u−1 for the SOBP as well as different scanning patterns of the irradiated field. Comparing their results revealed differences between the experimental k
Q
factors of up to 1.9% between the EC and the SOBP. To further investigate this unexpected difference, we performed additional k
Q
determinations for the EC of an 278 MeV u−1 monoenergetic carbon-ion beam and reevaluated the original data of Osinga-Blättermann et al (2017 Phys. Med. Biol.
62 2033–54). This new experimental data indicated no difference between the k
Q
factors for the EC and the SOBP and the reevaluation led to a substantial reduction of the originally published k
Q
factors for the EC of the 429 MeV u−1 beam (Osinga-Blättermann et al 2017 Phys. Med. Biol. 62 2033–54). Finally, no significant difference between the data for the EC and the data for the SOBP can be found within the standard measurement uncertainty of experimental k
Q
factors of 0.8%. The results presented here are intended to correct and replace the k
Q
data published by Osinga-Blättermann et al (2017 Phys. Med. Biol. 62 2033–54) and in Osinga-Blättermann and Krauss (2018 Phys. Med. Biol.
64 015009).
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Tessonnier T, Mein S, Walsh DWM, Schuhmacher N, Liew H, Cee R, Galonska M, Scheloske S, Schömers C, Weber U, Brons S, Debus J, Haberer T, Abdollahi A, Mairani A, Dokic I. FLASH dose-rate helium ion beams: first in vitro investigations. Int J Radiat Oncol Biol Phys 2021; 111:1011-1022. [PMID: 34343608 DOI: 10.1016/j.ijrobp.2021.07.1703] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE To establish and investigate the impact of dose, linear energy transfer (LET) and O2 concentration on biological response to ultra-high dose-rate (uHDR, FLASH) helium ion beams compared to standard dose-rate (SDR) irradiation. METHODS AND MATERIALS Beam delivery settings for raster-scanned helium ions at both uHDR and SDR were tuned to achieve >100 Gy/s and ∼0.1 Gy/s, respectively. For both SDR and uHDR, plan optimization and calibration for 10 × 10mm2 fields was performed to assess in vitro response at LET range of 4.5-16 keV/µm. Clonogenic survival assay was conducted at doses ranging from 2 Gy to 12 Gy in two human lung epithelial cell lines (A549 and H1437). Radiation induced nuclear γH2AX foci (RIF) were assessed in both epithelial cell lines and primary human pulmonary fibroblasts. RESULTS Average dose-rates achieved were 185 Gy/s and 0.12 Gy/s for uHDR and SDR, respectively. No differences in cellular response to SDR vs. uHDR were observed for all tested doses at 21% O2, as well as at 2 and 4 Gy at 1% O2. In contrast, at 1% O2 and dose threshold of ≳8Gy cell survival was higher and correlated with reduced nuclear γH2AX RIF signal indicating FLASH sparing effect in the investigated cell lines irradiated with uHDR as compared to SDR . CONCLUSION The first uHDR delivery of raster-scanned particle beams was achieved using helium ions, reaching FLASH-level dose-rates of >100 Gy/s. Baseline oxygen levels and delivered dose (≳ 8 Gy) play a pivotal role, irrespective of the studied cell lines, for observation of a sparing effect for helium ions.
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Affiliation(s)
- Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stewart Mein
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Clinical Cooperation Unit Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany; Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; German Cancer Consortium (DKTK) Core-Center Heidelberg, German Cancer Research Center (DKFZ), Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Dietrich W M Walsh
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Clinical Cooperation Unit Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany; Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; German Cancer Consortium (DKTK) Core-Center Heidelberg, German Cancer Research Center (DKFZ), Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Nora Schuhmacher
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Clinical Cooperation Unit Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany; Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; German Cancer Consortium (DKTK) Core-Center Heidelberg, German Cancer Research Center (DKFZ), Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Hans Liew
- Clinical Cooperation Unit Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany; Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; German Cancer Consortium (DKTK) Core-Center Heidelberg, German Cancer Research Center (DKFZ), Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Germany
| | - Rainer Cee
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Michael Galonska
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stefan Scheloske
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Christian Schömers
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Uli Weber
- GSI Helmholtzzentrum für Schwerionenforschung;Darmstadt, Germany
| | - Stephan Brons
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Jürgen Debus
- Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; German Cancer Consortium (DKTK) Core-Center Heidelberg, German Cancer Research Center (DKFZ), Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Germany
| | - Thomas Haberer
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Amir Abdollahi
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Clinical Cooperation Unit Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany; Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; German Cancer Consortium (DKTK) Core-Center Heidelberg, German Cancer Research Center (DKFZ), Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Andrea Mairani
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; National Centre of Oncological Hadrontherapy (CNAO), Medical Physics, Pavia, Italy.
| | - Ivana Dokic
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Clinical Cooperation Unit Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany; Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; German Cancer Consortium (DKTK) Core-Center Heidelberg, German Cancer Research Center (DKFZ), Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany.
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Holm KM, Jäkel O, Krauss A. Water calorimetry-based kQfactors for Farmer-type ionization chambers in the SOBP of a carbon-ion beam. Phys Med Biol 2021; 66. [PMID: 34153952 DOI: 10.1088/1361-6560/ac0d0d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/21/2021] [Indexed: 11/12/2022]
Abstract
The dosimetry of carbon-ion beams based on calibrated ionization chambers (ICs) still shows a significantly higher uncertainty compared to high-energy photon beams, a fact influenced mainly by the uncertainty of the correction factor for the beam qualitykQ. Due to a lack of experimental data,kQfactors in carbon-ion beams used today are based on theoretical calculations whose standard uncertainty is three times higher than that of photon beams. To reduce their uncertainty, in this work,kQfactors for two ICs were determined experimentally by means of water calorimetry for the spread-out Bragg peak of a carbon-ion beam, these factors are presented here for the first time. To this end, the absorbed dose to water in the12C-SOBP is measured using the water calorimeter developed at Physikalisch-Technische Bundesanstalt, allowing a direct calibration of the ICs used (PTW 30013 and IBA FC65G) and thereby an experimental determination of the chamber-specifickQfactors. Based on a detailed characterization of the irradiation field, correction factors for several effects that influence calorimetric and ionometric measurements were determined. Their contribution to an overall uncertainty budget of the finalkQfactors was determined, leading to a standard uncertainty forkQof 0.69%, which means a reduction by a factor of three compared to the theoretically calculated values. The experimentally determined values were expressed in accordance with TRS-398 and DIN 6801-1 and compared to the values given there. A maximum deviation of 2.3% was found between the experiment and the literature.
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Affiliation(s)
- Kim Marina Holm
- Department of Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig, Germany.,Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany.,Department of Physics and Astronomy, University of Heidelberg, Im Neuenheimer Feld 226, D-69120 Heidelberg, Germany
| | - Oliver Jäkel
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany.,Heidelberg Ion Beam Therapy Center (HIT), University Hospital Heidelberg, Im Neuenheimer Feld 450, D-69120 Heidelberg, Germany
| | - Achim Krauss
- Department of Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig, Germany
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Holm KM, Yukihara EG, Ahmed MF, Greilich S, Jäkel O. Triple channel analysis of Gafchromic EBT3 irradiated with clinical carbon-ion beams. Phys Med 2021; 87:123-130. [PMID: 34146794 DOI: 10.1016/j.ejmp.2021.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 11/16/2022] Open
Abstract
Self-developing radiochromic film is widely used in radiotherapy QA procedures. To compensate for typical film inhomogeneities, the triple channel analysis method is commonly used for photon-irradiated film. We investigated the applicability of this method for GafchromicTMEBT3 (Ashland) film irradiated with a clinically used carbon-ion beam. Calibration curves were taken from EBT3 film specimens irradiated with monoenergetic carbon-ion beams of different doses. Measurements of the lateral field shape and homogeneity were performed in the middle of a passively modulated spread-out Bragg peak and compared to simultaneous characterization by means of a 2D ionization chamber array. Additional measurements to investigate the applicability of EBT3 for quality assurance (QA) measurement in carbon-ion beams were performed. The triple-channel analysis reduced the relative standard deviation of the doses in a uniform carbon ion field by 30% (from 1.9% to 1.3%) and reduced the maximum deviation by almost a factor of 3 (from 28.6% to 9.8%), demonstrating the elimination of film artifacts. The corrected film signal showed considerably improved image quality and quantitative agreement with the ionization chamber data, thus providing a clear rationale for the usage of the triple channel analysis in carbon-beam QA.
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Affiliation(s)
- Kim Marina Holm
- Department of Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, Braunschweig D-38116, Germany; Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany; Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany; Department of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, Heidelberg D-69120, Germany.
| | - Eduardo G Yukihara
- Department of Radiation Safety and Security, Paul Scherrer Institute, Forschungsstrasse 111, Villigen PSI 5232, Switzerland
| | - Md Foiez Ahmed
- Sun Nuclear Corporation, 3275 Suntree Blvd, Melbourne, Florida 32940, USA
| | - Steffen Greilich
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany; Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Oliver Jäkel
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany; Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany; Heidelberg Ion Beam Therapy Center (HIT), University Hospital Heidelberg, Im Neuenheimer Feld 450, Heidelberg D-69120, Germany
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Simeonov Y, Weber U, Schuy C, Engenhart-Cabillic R, Penchev P, Durante M, Zink K. Monte Carlo simulations and dose measurements of 2D range-modulators for scanned particle therapy. Z Med Phys 2020; 31:203-214. [PMID: 32711939 DOI: 10.1016/j.zemedi.2020.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/17/2020] [Accepted: 06/22/2020] [Indexed: 10/23/2022]
Abstract
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 2D range-modulator has some distinct advantages that can be highly useful for different research projects in particle therapy facilities. Most importantly, it creates an instantaneous, quasi-static irradiation field with only one energy, thus decreasing irradiation time tremendously. In addition, it can be manufactured fast and cost efficiently and its SOBP width and shape can be adjusted easily for the specific purpose/experiment. As the modulator is a static element, there is no need for rotation (e.g. like in a modulation wheel) or lateral oscillation and due to the small base structure period it can be positioned close to the target. Two different rapid prototyping manufacturing techniques were utilized. The modulation properties of one polymer and one steel modulator were investigated with both simulations and measurements. For this purpose, a sophisticated water phantom system (WERNER), that can perform fast, completely automated and high resolution dose measurements, was developed. Using WERNER, the dose distribution of a modulator can be verified quickly and reliably, both during experiments, as well as in a time constrained clinical environment. The maximum deviation between the Monte Carlo simulations and dose measurements in the spread-out Bragg peak region was 1.4% and 4% for the polymer and steel modulator respectively. They were able to create spread-out Bragg peaks with a high degree of dose homogeneity, thus validating the whole process chain, from the mathematical optimization and modulator development, to manufacturing, MC simulations and dose measurements. Combining the convenience, flexibility and cost-effectiveness of rapid prototyping with the advantages of highly customizable modulators, that can be adapted for different experiments, the 2D range-modulator is considered a very useful tool for a variety of research objectives. Moreover, we have successfully shown that the manufacturing of 2D modulators with high quality and high degree of homogeneity is possible, paving the way for the further development of the more complex 3D range-modulators, which are considered a viable option for the very fast treatment of moving targets and/or FLASH irradiation.
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Affiliation(s)
- Yuri Simeonov
- Institut für Medizinische Physik und Strahlenschutz (IMPS), University of Applied Sciences, Giessen, Germany; Philipps-University, Marburg, Germany.
| | - Uli Weber
- Biophysics Division, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - Christoph Schuy
- Biophysics Division, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - Rita Engenhart-Cabillic
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany
| | - Petar Penchev
- Institut für Medizinische Physik und Strahlenschutz (IMPS), University of Applied Sciences, Giessen, Germany
| | - Marco Durante
- Biophysics Division, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany; Technical University of Darmstadt, Institute for Condensed Matter Physics, Germany
| | - Klemens Zink
- Institut für Medizinische Physik und Strahlenschutz (IMPS), University of Applied Sciences, Giessen, Germany; Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany; Marburg Ion Beam Therapy Center (MIT), Marburg, Germany
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