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Frederiksen AT, Jensen MB, Poulsen PR, Bassler N, Sørensen BS, Sitarz M. Evaluation of in vitro irradiation setup: Designed for the horizontal beamline at the Danish Centre for Particle Therapy. Acta Oncol 2024; 63:23-27. [PMID: 38349282 DOI: 10.2340/1651-226x.2024.19657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/02/2023] [Indexed: 02/15/2024]
Abstract
BACKGROUND Radiobiological experimental setups are challenged by precise sample positioning along depth dose profile, scattering conditions, and practical difficulties that must be addressed in individual designs. The aim of this study was to produce cell survival curves with several irradiation modalities, by using a setup designed at the Danish Centre for Particle Therapy (DCPT) for in vitro proton irradiations using a horizontal beam line and thereby evaluating the setups use for in vitro irradiations experiments. MATERIALS AND METHODS The setup is a water phantom suitable for in vitro research with multiple irradiation modalities, in particular the pencil scanning proton beam available from a horizontal experimental beamline. The phantom included a water tank of 39.0 × 17.0 × 20.5 cm. Cell survival-curves were produced using the cell line V79 Chinese hamster lung fibroblast cells (V79s) in biological triplicates of clonogenic assays. Cell survival curves were produced with both a 18 MeV electron beam, 6 MV photon beam, and a Spread-Out Bragg Peak (SOBP) proton beam formed by pristine energies of 85-111 MeV where three positions were examined. RESULTS Survival curves with uncertainty areas were made for all modalities. Dosimetric uncertainty amounted to, respectively, 4%, 3% and 3% for proton, electron, and high energy photon irradiations. Cell survival fraction uncertainty was depicted as the standard deviation between replications of the experiment. CONCLUSION Cell survival curves could be produced with acceptable uncertainties using this novel water phantom and cellular laboratory workflow. The setup is useful for future in vitro irradiation experiments.
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Affiliation(s)
- Anders Tobias Frederiksen
- Danish Centre for Particle Therapy (DCPT), Aarhus University Hospital, Aarhus Denmark; Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark; Institute for Biomedicine, Aarhus University, Aarhus, Denmark; Department of Public Health, Department of Biostatistics, Aarhus University, Aarhus, Denmark.
| | - Morten Bjørn Jensen
- Danish Centre for Particle Therapy (DCPT), Aarhus University Hospital, Aarhus Denmark; Department for Medical Physics, Aarhus University Hospital, Aarhus, Denmark
| | - Per Rugaard Poulsen
- Danish Centre for Particle Therapy (DCPT), Aarhus University Hospital, Aarhus Denmark
| | - Niels Bassler
- Danish Centre for Particle Therapy (DCPT), Aarhus University Hospital, Aarhus Denmark
| | - Brita Singers Sørensen
- Danish Centre for Particle Therapy (DCPT), Aarhus University Hospital, Aarhus Denmark; Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Mateusz Sitarz
- Danish Centre for Particle Therapy (DCPT), Aarhus University Hospital, Aarhus Denmark
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Addo DA, Kaufmann EE, Tagoe SN, Kyere AK. Characterization of GafChromic EBT2 film dose measurements using a tissue-equivalent water phantom for a Theratron® Equinox Cobalt-60 teletherapy machine. PLoS One 2022; 17:e0271000. [PMID: 35984784 PMCID: PMC9390906 DOI: 10.1371/journal.pone.0271000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 06/21/2022] [Indexed: 11/19/2022] Open
Abstract
Purpose
In vivo dosimetry is a quality assurance tool that provides post-treatment measurement of the absorbed dose as delivered to the patient. This dosimetry compares the prescribed and measured dose delivered to the target volume. In this study, a tissue-equivalent water phantom provided the simulation of the human environment. The skin and entrance doses were measured using GafChromic EBT2 film for a Theratron® Equinox Cobalt-60 teletherapy machine.
Methods
We examined the behaviors of unencapsulated films and custom-made film encapsulation. Films were cut to 1 cm × 1 cm, calibrated, and used to assess skin dose depositions and entrance dose. We examined the response of the film for variations in field size, source to skin distance (SSD), gantry angle and wedge angle.
Results
The estimated uncertainty in EBT2 film for absorbed dose measurement in phantom was ±1.72%. Comparison of the measurements of the two film configurations for the various irradiation parameters were field size (p = 0.0193, α = 0.05, n = 11), gantry angle (p = 0.0018, α = 0.05, n = 24), SSD (p = 0.1802, α = 0.05, n = 11) and wedge angle (p = 0.6834, α = 0.05, n = 4). For a prescribed dose of 200 cGy and at reference conditions (open field 10 cm x 10 cm, SSD = 100 cm, and gantry angle = 0º), the measured skin dose using the encapsulation material was 70% while that measured with the unencapsulated film was 24%. At reference irradiation conditions, the measured skin dose using the unencapsulated film was higher for open field configurations (24%) than wedged field configurations (19%). Estimation of the entrance dose using the unencapsulated film was within 3% of the prescribed dose.
Conclusions
GafChromic EBT2 film measurements were significantly affected at larger field sizes and gantry angles. Furthermore, we determined a high accuracy in entrance dose estimations using the film.
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Affiliation(s)
- Daniel Akwei Addo
- Department of Computer Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- * E-mail:
| | - Elsie Effah Kaufmann
- Department of Biomedical Engineering, School of Engineering Sciences, University of Ghana, Legon, Accra, Ghana
| | - Samuel Nii Tagoe
- National Radiotherapy Oncology and Nuclear Medicine Centre, Korle-Bu, Accra, Ghana
- School of Biomedical and Allied health Sciences, University of Ghana, Accra, Ghana
| | - Augustine Kwame Kyere
- Medical Physics Department, Graduate School of Nuclear and Allied Sciences, University of Ghana, Atomic, Accra, Ghana
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Deycmar S, Mara E, Kerschbaum-Gruber S, Waller V, Georg D, Pruschy M. Ganetespib selectively sensitizes cancer cells for proximal and distal spread-out Bragg peak proton irradiation. Radiat Oncol 2022; 17:72. [PMID: 35410422 PMCID: PMC8996402 DOI: 10.1186/s13014-022-02036-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 03/20/2022] [Indexed: 02/03/2023] Open
Abstract
Objective Hypersensitivity towards proton versus photon irradiation was demonstrated in homologous recombination repair (HRR)-deficient cell lines. Hence, combined treatment concepts targeting HRR provide a rational for potential pharmaceutical exploitation. The HSP90 inhibitor ganetespib (STA-9090) downregulates a multitude of HRR-associated proteins and sensitizes for certain chemotherapeutics. Thus, the radiosensitizing effect of HSP90-inhibiting ganetespib was investigated for reference photon irradiation and proton irradiation at a proximal and distal position in a spread-out Bragg peak (SOBP). Methods A549 and FaDu cells were treated with low-dose (2 nM resp. 1 nM) ganetespib and irradiated with 200 kV photons. Proton irradiation was performed at a proximal and a distal position within a SOBP, with corresponding dose-averaged linear-energy transfer (LETD) values of 2.1 and 4.5 keV/µm, respectively. Cellular survival data was fitted to the linear-quadratic model to calculate relative biological effectiveness (RBE) and the dose-modifying factor (DMF). Additionally, A549 cells were treated with increasing doses of ganetespib and investigated by flow cytometry, immunoblotting, and immunofluorescence microscopy to investigate cell cycle distribution, Rad51 protein levels, and γH2AX foci, respectively. Results Low-dosed ganetespib significantly sensitized both cancer cell lines exclusively for proton irradiation at both investigated LETD, resulting in increased RBE values of 10–40%. In comparison to photon irradiation, the fraction of cells in S/G2/M phase was elevated in response to proton irradiation with 10 nM ganetespib consistently reducing this population. No changes in cell cycle distribution were detected in unirradiated cells by ganetespib alone. Protein levels of Rad51 are downregulated in irradiated A549 cells by 10 nM and also 2 nM ganetespib within 24 h. Immunofluorescence staining demonstrated similar induction and removal of γH2AX foci, irrespective of irradiation type or ganetespib administration. Conclusion Our findings illustrate a proton-specific sensitizing effect of low-dosed ganetespib in both employed cell lines and at both investigated SOBP positions. We provide additional experimental data on cellular response and a rational for future combinatorial approaches with proton radiotherapy. Supplementary Information The online version contains supplementary material available at 10.1186/s13014-022-02036-z.
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Dunn L, Godwin G, Hellyer J, Xu X. A method for time‐independent film dosimetry: Can we obtain accurate patient‐specific QA results at any time postirradiation? J Appl Clin Med Phys 2022; 23:e13534. [PMID: 35049118 PMCID: PMC8906213 DOI: 10.1002/acm2.13534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 12/15/2021] [Accepted: 12/30/2021] [Indexed: 11/09/2022] Open
Affiliation(s)
- Leon Dunn
- St Vincent's GenesisCare Centre for radiation oncology St Vincent's Hospital Basement Level Building C, 41 Victoria Parade, Fitzroy VIC 3065 Melbourne Victoria 3065 Australia
| | - Guy Godwin
- Redland Icon Cancer Care Bayside Business Park, 16/24 Weippin St, Cleveland QLD Brisbane Queensland 4163 Australia
| | - James Hellyer
- Macquarie University GenesisCare Centre for radiation oncology Hospital Building Suite 1, Level B2, 3 Technology Pl, Macquarie University NSW Sydney New South Wales 2109 Australia
| | - Xiaolei Xu
- St Vincent's GenesisCare Centre for radiation oncology St Vincent's Hospital Basement Level Building C, 41 Victoria Parade, Fitzroy VIC 3065 Melbourne Victoria 3065 Australia
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Lohberger B, Glänzer D, Eck N, Kerschbaum-Gruber S, Mara E, Deycmar S, Madl T, Kashofer K, Georg P, Leithner A, Georg D. Activation of efficient DNA repair mechanisms after photon and proton irradiation of human chondrosarcoma cells. Sci Rep 2021; 11:24116. [PMID: 34916568 PMCID: PMC8677811 DOI: 10.1038/s41598-021-03529-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/24/2021] [Indexed: 01/02/2023] Open
Abstract
Although particle therapy with protons has proven to be beneficial in the treatment of chondrosarcoma compared to photon-based (X-ray) radiation therapy, the cellular and molecular mechanisms have not yet been sufficiently investigated. Cell viability and colony forming ability were analyzed after X-ray and proton irradiation (IR). Cell cycle was analyzed using flow cytometry and corresponding regulator genes and key players of the DNA repair mechanisms were measured using next generation sequencing, protein expression and immunofluorescence staining. Changes in metabolic phenotypes were determined with nuclear magnetic resonance spectroscopy. Both X-ray and proton IR resulted in reduced cell survival and a G2/M phase arrest of the cell cycle. Especially 1 h after IR, a significant dose-dependent increase of phosphorylated γH2AX foci was observed. This was accompanied with a reprogramming in cellular metabolism. Interestingly, within 24 h the majority of clearly visible DNA damages were repaired and the metabolic phenotype restored. Involved DNA repair mechanisms are, besides the homology directed repair (HDR) and the non-homologous end-joining (NHEJ), especially the mismatch mediated repair (MMR) pathway with the key players EXO1, MSH3, and PCNA. Chondrosarcoma cells regenerates the majority of DNA damages within 24 h. These molecular mechanisms represent an important basis for an improved therapy.
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Affiliation(s)
- Birgit Lohberger
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5-7, 8036, Graz, Austria.
| | - Dietmar Glänzer
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5-7, 8036, Graz, Austria
| | - Nicole Eck
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5-7, 8036, Graz, Austria
| | - Sylvia Kerschbaum-Gruber
- Department of Radiation Oncology, Medical University of Vienna, 1090, Vienna, Austria
- MedAustron Ion Therapy Center, 2700, Wiener Neustadt, Austria
| | - Elisabeth Mara
- MedAustron Ion Therapy Center, 2700, Wiener Neustadt, Austria
- University of Applied Science, 2700, Wiener Neustadt, Austria
| | - Simon Deycmar
- Laboratory for Applied Radiobiology, University Zurich, 8006, Zurich, Switzerland
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging Molecular Biology and Biochemistry, Medical University of Graz, 8010, Graz, Austria
- BioTechMed-Graz, 8010, Graz, Austria
| | - Karl Kashofer
- Institute of Pathology, Medical University of Graz, 8010, Graz, Austria
| | - Petra Georg
- MedAustron Ion Therapy Center, 2700, Wiener Neustadt, Austria
| | - Andreas Leithner
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5-7, 8036, Graz, Austria
| | - Dietmar Georg
- Department of Radiation Oncology, Medical University of Vienna, 1090, Vienna, Austria
- MedAustron Ion Therapy Center, 2700, Wiener Neustadt, Austria
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Hashemi Z, Tatari M, Naik H. Simulation of dose distribution and secondary particle production in proton therapy of brain tumor. Rep Pract Oncol Radiother 2020; 25:927-933. [PMID: 33088228 DOI: 10.1016/j.rpor.2020.08.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 08/01/2020] [Accepted: 08/26/2020] [Indexed: 11/18/2022] Open
Abstract
Aim The aim of this study is simulation of the proton depth-dose distribution and dose evaluation of secondary particles in proton therapy of brain tumor using the GEANT4 and FLUKA Monte Carlo codes. Background Proton therapy is a treatment method for variety of tumors such as brain tumor. The most important feature of high energy proton beams is the energy deposition as a Bragg curve and the possibility of creating the spread out Bragg peak (SOBP) for full coverage of the tumor. Materials and methods A spherical tumor with the radius of 1 cm in the brain is considered. A SNYDER head phantom has been irradiated with 30-130 MeV proton beam energy. A PMMA modulator wheel is used for covering the tumor. The simulations are performed using the GEANT4 and FLUKA codes. Results Using a modulator wheel, the Spread Out Bragg Peak longitudinally and laterally covers the tumor. Flux and absorbed dose of secondary particles produced by nuclear interactions of protons with elements in the head are considerably small compared to protons. Conclusions Using 76.85 MeV proton beam and a modulator wheel, the tumor can be treated accurately in the 3-D, so that the distribution of proton dose in the surrounding tissues is very low. The results show that more than 99% of the total dose of secondary particles and protons is absorbed in the tumor.
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Affiliation(s)
- Zahra Hashemi
- Physics Department, Faculty of Science, Yazd University, Yazd 89195-741, Iran
| | - Mansoureh Tatari
- Physics Department, Faculty of Science, Yazd University, Yazd 89195-741, Iran
| | - Haladhara Naik
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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Mara E, Clausen M, Khachonkham S, Deycmar S, Pessy C, Dörr W, Kuess P, Georg D, Gruber S. Investigating the impact of alpha/beta and LET d on relative biological effectiveness in scanned proton beams: An in vitro study based on human cell lines. Med Phys 2020; 47:3691-3702. [PMID: 32347564 PMCID: PMC7496287 DOI: 10.1002/mp.14212] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 04/03/2020] [Accepted: 04/13/2020] [Indexed: 12/15/2022] Open
Abstract
PURPOSE A relative biological effectiveness (RBE) of 1.1 is commonly used in clinical proton therapy, irrespective of tissue type and depth. This in vitro study was conducted to quantify the RBE of scanned protons as a function of the dose-averaged linear energy transfer (LETd ) and the sensitivity factor (α/ß)X . Additionally, three phenomenological models (McNamara, Rørvik, and Jones) and one mechanistic model (repair-misrepair-fixation, RMF) were applied to the experimentally derived data. METHODS Four human cell lines (FaDu, HaCat, Du145, SKMel) with differential (α/ß)X ratios were irradiated in a custom-designed irradiation setup with doses between 0 and 6 Gy at proximal, central, and distal positions of a 80 mm spread-out Bragg peak (SOBP) centered at 80 mm (setup A: proton energies 66.5-135.6 MeV) and 155 mm (setup B: proton energies 127.2-185.9 MeV) depth, respectively. LETd values at the respective cell positions were derived from Monte Carlo simulations performed with the treatment planning system (TPS, RayStation). Dosimetric measurements were conducted to verify dose homogeneity and dose delivery accuracy. RBE values were derived for doses that resulted in 90 % (RBE90 ) and 10 % (RBE10 ) of cell survival, and survival after a 0.5 Gy dose (RBE0.5Gy ), 2 Gy dose (RBE2Gy ), and 6 Gy dose (RBE6Gy ). RESULTS LETd values at sample positions were 1.9, 2.1, 2.5, 2.8, 4.1, and 4.5 keV/µm. For the cell lines with high (α/ß)X ratios (FaDu, HaCat), the LETd did not impact on the RBE. For low (α/ß)X cell lines (Du145, SKMel), LQ-derived survival curves indicated a clear correlation of LETd and RBE. RBE90 values up to 2.9 and RBE10 values between 1.4 and 1.8 were obtained. Model-derived RBE predictions slightly overestimated the RBE for the high (α/ß)X cell lines, although all models except the Jones model provided RBE values within the experimental uncertainty. For low (α/ß)X cell lines, no agreement was found between experiments and model predictions, that is, all models underestimated the measured RBE. CONCLUSIONS The sensitivity parameter (α/ß)X was observed to be a major influencing factor for the RBE of protons and its sensitivity toward LETd changes. RBE prediction models are applicable for high (α/ß)X cell lines but do not estimate RBE values with sufficient accuracy in low (α/ß)X cell lines.
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Affiliation(s)
- Elisabeth Mara
- Department of Radiation Oncology/Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.,University of Applied Science, Wiener Neustadt, Austria
| | - Monika Clausen
- Department of Radiation Oncology/Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Suphalak Khachonkham
- Department of Radiation Oncology/Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.,Division of Radiation Therapy, Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Simon Deycmar
- Laboratory of Applied Radiobiology, Department of Radiation Oncology, University Hospital Zürich, Zürich, Switzerland
| | - Clara Pessy
- Department of Radiation Oncology/Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Dörr
- Department of Radiation Oncology/Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Peter Kuess
- Department of Radiation Oncology/Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.,EBG MedAustron GmbH, Wiener Neustadt, Austria
| | - Dietmar Georg
- Department of Radiation Oncology/Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.,EBG MedAustron GmbH, Wiener Neustadt, Austria
| | - Sylvia Gruber
- Department of Radiation Oncology/Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.,EBG MedAustron GmbH, Wiener Neustadt, Austria
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Resch AF, Heyes PD, Fuchs H, Bassler N, Georg D, Palmans H. Dose- rather than fluence-averaged LET should be used as a single-parameter descriptor of proton beam quality for radiochromic film dosimetry. Med Phys 2020; 47:2289-2299. [PMID: 32166764 PMCID: PMC7318138 DOI: 10.1002/mp.14097] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/24/2020] [Accepted: 02/05/2020] [Indexed: 11/06/2022] Open
Abstract
PURPOSE The dose response of Gafchromic EBT3 films exposed to proton beams depends on the dose, and additionally on the beam quality, which is often quantified with the linear energy transfer (LET) and, hence, also referred to as LET quenching. Fundamentally different methods to determine correction factors for this LET quenching effect have been reported in literature and a new method using the local proton fluence distribution differential in LET is presented. This method was exploited to investigate whether a more practical correction based on the dose- or fluence-averaged LET is feasible in a variety of clinically possible beam arrangements. METHODS The relative effectiveness (RE) was characterized within a high LET spread-out Bragg peak (SOBP) in water made up by the six lowest available energies (62.4-67.5 MeV, configuration " b 1 ") resulting in one of the highest clinically feasible dose-averaged LET distributions. Additionally, two beams were measured where a low LET proton beam (252.7 MeV) was superimposed on " b 1 ", which contributed either 50% of the initial particle fluence or 50% of the dose in the SOBP, referred to as configuration " b 2 " and " b 3 ," respectively. The proton LET spectrum was simulated with GATE/Geant4 at all measurement positions. The net optical density change differential in LET was integrated over the local proton spectrum to calculate the net optical density and therefrom the beam quality correction factor. The LET dependence of the film response was accounted for by an LET dependence of one of the three parameters in the calibration function and was determined from inverse optimization using measurement " b 1 ." This method was then validated on the measurements of " b 2 " and " b 3 " and subsequently used to calculate the RE at 900 positions in nine clinically relevant beams. The extrapolated RE set was used to derive a simple linear correction function based on dose-averaged LET ( L d ) and verify the validity in all points of the comprehensive RE set. RESULTS The uncorrected film dose deviated up to 26% from the reference dose, whereas the corrected film dose agreed within 3% in all three beams in water (" b 1 ", " b 2 " and " b 3 "). The LET dependence of the calibration function started to strongly increase around 5 keV/μm and flatten out around 30 keV/μm. All REs calculated from the proton fluence in the nine simulated beams could be approximated with a linear function of dose-averaged LET (RE = 1.0258-0.0211 μm/keV L d ). However, no functional relationship of RE- and fluence-averaged LET could be found encompassing all beam energies and modulations. CONCLUSIONS The film quenching was found to be nonlinear as a function of proton LET as well as of the dose-averaged LET. However, the linear relation of RE on dose-averaged LET was a good approximation in all cases. In contrast to dose-averaged LET, fluence-averaged LET could not describe the RE when multiple beams were applied.
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Affiliation(s)
- Andreas Franz Resch
- Division Medical Radiation Physics, Department of Radiotherapy, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/AKH Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Paul David Heyes
- Division Medical Radiation Physics, Department of Radiotherapy, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/AKH Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Hermann Fuchs
- Division Medical Radiation Physics, Department of Radiotherapy, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/AKH Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Niels Bassler
- Medical Radiation Physics, Department of Physics, Stockholm University, Stockholm, Sweden.,Department of Oncology and Pathology, Medical Radiation Physics, Karolinska Institutet, Stockholm, Sweden.,Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Dietmar Georg
- Division Medical Radiation Physics, Department of Radiotherapy, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/AKH Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Hugo Palmans
- MedAustron Ion Therapy Centre/EBG MedAustron, Marie-Curie-Straße 5, 2700, Wiener Neustadt, Austria.,Medical Radiation Science, National Physical Laboratory, Hampton Road, TW11 0LW, Teddington, United Kingdom
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