EBG MedAustron

Austria

EBG MedAustron

Austria
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Wastl A.,EBG MedAustron | Kulenkampff T.,EBG MedAustron | Nowak S.,EBG MedAustron | Garonna A.,EBG MedAustron
IPAC 2016 - Proceedings of the 7th International Particle Accelerator Conference | Year: 2016

During the commissioning of the synchrotron-based MedAustron accelerator facility, the analysis and interpretation of data of various sources was required. A dedicated framework was developed to analyze the raw data provided by the accelerator control system (ACS). A tested and documented software core with a simple and standardized interface allows also non-programming professionals to easily base their applications on this framework which is essential to efficiently make progress in the dynamic environment of commissioning. This document presents the structure of the framework, the interface between the software core and higher level applications and gives an example using all framework levels. Copyright © 2016 CC-BY-3.0 and by the respective authors.


Wastl A.,Atominstitut Vienna | Benedikt M.,CERN | Garonna A.,EBG MedAustron
6th International Particle Accelerator Conference, IPAC 2015 | Year: 2015

MedAustron is a synchrotron based hadron therapy and research center in Wiener Neustadt, Austria, which currently is under commissioning for the first patient treatment. The High Energy Beam Transfer Line (HEBT) consists of multiple functional modules amongst which the phase-shifterstepper PSS is the most important module located where the dispersion from the synchrotron is zero and upstream of the switching magnet to the first irradiation room. The PSS is used to control the beam size for the downstream modules and for this scope rotates the beam in horizontal phase space by adjusting the phase advance. This functionality is used in this study to measure beam profiles for multiple phase space angles which act as input for a tomographic reconstruction. Simulation and measurement results are presented. Copyright © 2015 CC-BY-3.0 and by the respective authors.


Wastl A.,EBG MedAustron | Hager M.,EBG MedAustron | Regodic M.,EBG MedAustron
6th International Particle Accelerator Conference, IPAC 2015 | Year: 2015

MedAustron is a synchrotron-based cancer therapy and non-clinical research center located in Austria. Its accelerator is currently being commissioned prior to first medical treatment. During the tuning of the machine, many iterations of measurements involving several parameter changes are performed in order to optimize the accelerator's performance. An operation and measurement software framework called 'Operational Application Framework' (OpApp) has been developed for this purpose. It follows a modular approach and provides basic methods like 'write to file' or 'measure beam position monitor'. By appropriately combining modules, OpApps performing automatized measurements and complex procedures can be created. A detailed description of the setup as well as examples of use are provided here. Copyright © 2015 CC-BY-3.0 and by the respective authors.


Fuchs H.,Christian Doppler Laboratory | Fuchs H.,Medical University of Vienna | Vatnitsky S.,EBG MedAustron | Stock M.,EBG MedAustron | And 3 more authors.
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2017

Purpose To systematically evaluate simulated characteristic multiple Coulomb scattering (MCS) angles with GATE/Geant4 against experimental data for 158.6 MeV proton beams. Methods The open source toolkit GATE alongside Geant4 in release 9.5 patch 02, 9.6 patch 03, 10.0 patch 02, 10.1, and 10.2 patch 02 were used to simulate a 158.6 MeV collimated monoenergetic proton beam impinging on a scattering disc of various materials and thicknesses: in total 144 different set-ups were investigated per Geant4 release and compared to measured data. Data was read out into a phase space providing information of individual particle momentum. For analysis a one dimensional Gaussian was fit to the beam profile and the multiple Coulomb scattering angles were calculated using the ROOT toolkit. Results The agreement between simulated and experimental data was found to be dependent on the Geant4 release. On average an agreement of -1.1% with a standard deviation of 3.4% was reached with Geant4 release 10.2. Increased differences were found for very thick targets close to the particle range and for older Geant4 versions employing the previous electromagnetic model, Urban MCS. Conclusion Multiple Coulomb scattering algorithms implemented in the latest Geant4 releases and in particular Geant4.10.2 showed a very satisfactory agreement with measured data for applications in proton pencil beam scanning. © 2017 Elsevier B.V.


Ableitinger A.,EBG MedAustron | Vatnitsky S.,EBG MedAustron | Herrmann R.,University of Aarhus | Herrmann R.,Aarhus University Hospital | And 10 more authors.
Radiotherapy and Oncology | Year: 2013

Background and purpose In the next few years the number of facilities providing ion beam therapy with scanning beams will increase. An auditing process based on an end-to-end test (including CT imaging, planning and dose delivery) could help new ion therapy centres to validate their entire logistic chain of radiation delivery. An end-to-end procedure was designed and tested in both scanned proton and carbon ion beams, which may also serve as a dosimetric credentialing procedure for clinical trials in the future. The developed procedure is focused only on physical dose delivery and the validation of the biological dose is out of scope of the current work. Materials and methods The audit procedure was based on a homogeneous phantom that mimics the dimension of a head (20 × 20 × 21 cm3). The phantom can be loaded either with an ionisation chamber or 20 alanine dosimeters plus 2 radiochromic EBT films. Dose verification aimed at measuring a dose of 10 Gy homogeneously delivered to a virtual-target volume of 8 × 8 × 12 cm3. In order to interpret the readout of the irradiated alanine dosimeters additional Monte Carlo simulations were performed to calculate the energy dependent detector response of the particle fluence in the alanine detector. A pilot run was performed with protons and carbon ions at the Heidelberg Ion Therapy facility (HIT). Results The mean difference of the absolute physical dose measured with the alanine dosimeters compared with the expected dose from the treatment planning system was -2.4 ± 0.9% (1σ) for protons and -2.2 ± 1.1% (1σ) for carbon ions. The measurements performed with the ionisation chamber indicate this slight underdosage with a dose difference of -1.7% for protons and -1.0% for carbon ions. The profiles measured by radiochromic films showed an acceptable homogeneity of about 3%. Conclusions Alanine dosimeters are suitable detectors for dosimetry audits in ion beam therapy and the presented end-to-end test is feasible. If further studies show similar results, this dosimetric audit could be implemented as a credentialing procedure for clinical proton and carbon beam delivery. © 2013 Elsevier Ireland Ltd. All rights reserved.


Solevi P.,EBG MedAustron | Solevi P.,University of Valencia | Solevi P.,Otto Von Guericke University of Magdeburg | Magrin G.,EBG MedAustron | And 2 more authors.
Physics in Medicine and Biology | Year: 2015

Ion-beam therapy provides a high dose conformity and increased radiobiological effectiveness with respect to conventional radiation-therapy. Strict constraints on the maximum uncertainty on the biological weighted dose and consequently on the biological weighting factor require the determination of the radiation quality, defined as the types and energy spectra of the radiation at a specific point. However the experimental determination of radiation quality, in particular for an internal target, is not simple and the features of ion interactions and treatment delivery require dedicated and optimized detectors. Recently chemical vapor deposition (CVD) diamond detectors have been suggested as ion-beam therapy microdosimeters. Diamond detectors can be manufactured with small cross sections and thin shapes, ideal to cope with the high fluence rate. However the sensitive volume of solid state detectors significantly deviates from conventional microdosimeters, with a diameter that can be up to 1000 times the height. This difference requires a redefinition of the concept of sensitive thickness and a deep study of the secondary to primary radiation, of the wall effects and of the impact of the orientation of the detector with respect to the radiation field. The present work intends to study through Monte Carlo simulations the impact of the detector geometry on the determination of radiation quality quantities, in particular on the relative contribution of primary and secondary radiation. The dependence of microdosimetric quantities such as the unrestricted linear energy L and the lineal energy y are investigated for different detector cross sections, by varying the particle type (carbon ions and protons) and its energy. © 2015 Institute of Physics and Engineering in Medicine.


Moyers M.F.,Loma Linda University | Vatnitsky A.S.,Robert Packard Hospital | Vatnitsky S.M.,EBG MedAustron
Medical Physics | Year: 2011

Purpose: Previous dosimetry protocols allowed calibrations of proton beamline dose monitors to be performed in plastic phantoms. Nevertheless, dose determinations were referenced to absorbed dose-to-muscle or absorbed dose-to-water. The IAEA Code of Practice TRS 398 recommended that dose calibrations be performed with ionization chambers only in water phantoms because plastic-to-water dose conversion factors were not available with sufficient accuracy at the time of its writing. These factors are necessary, however, to evaluate the difference in doses delivered to patients if switching from calibration in plastic to a protocol that only allows calibration in water.Methods: This work measured polystyrene-to-water dose conversion factors for this purpose. Uncertainties in the results due to temperature, geometry, and chamber effects were minimized by using special experimental set-up procedures. The measurements were validated by Monte Carlo simulations.Results: At the peak of non-range-modulated beams, measured polystyrene-to-water factors ranged from 1.015 to 1.024 for beams with ranges from 36 to 315 mm. For beams with the same ranges and medium sized modulations, the factors ranged from 1.005 to 1.019. The measured results were used to generate tables of polystyrene-to-water dose conversion factors.Conclusions: The dose conversion factors can be used at clinical proton facilities to support beamline and patient specific dose per monitor unit calibrations performed in polystyrene phantoms. © 2011 American Association of Physicists in Medicine.


Magrin G.,EBG MedAustron | Mayer R.,EBG MedAustron
Modern Physics Letters A | Year: 2015

The information of the dose is not sufficiently describing the biological effects of ions on tissue since it does not express the radiation quality, i.e. the heterogeneity of the processes due to the slowing-down and the fragmentation of the particles when crossing a target. Depending on different circumstances, the radiation quality can be determined using measurements, calculations, or simulations. Microdosimeters are the primary tools used to provide the experimental information of the radiation quality and their role is becoming crucial for the recent clinical developments in particular with carbon ion therapy. Microdosimetry is strongly linked to the biological effectiveness of the radiation since it provides the physical parameters which explicitly distinguish the radiation for its capability of damaging cells. In the framework of ion-beam therapy microdosimetry can be used in the preparation of the treatment to complement radiobiological experiments and to analyze the modification of the radiation quality in phantoms. A more ambitious goal is to perform the measurements during the irradiation procedure to determine the non-targeted radiation and, more importantly, to monitor the modification of the radiation quality inside the patient. These procedures provide the feedback of the treatment directly beneficial for the single patient but also for the characterization of the biological effectiveness in general with advantages for all future treatment. Traditional and innovative tools are currently under study and an outlook of present experience and future development is presented here. © 2015 World Scientific Publishing Company.


Strobele J.,EBG MedAustron | Strobele J.,Medical University of Vienna | Schreiner T.,EBG MedAustron | Fuchs H.,EBG MedAustron | And 3 more authors.
Zeitschrift fur Medizinische Physik | Year: 2012

Purpose: The aim of this study was to investigate the basic features of helium ions for their possible application in advanced radiotherapy and to benchmark them against protons, the current particle of choice in the low linear energy transfer (LET) range. Material and methods: Geant4 Application for Emission Tomography (GATE) simulations were performed with beams of 1x107 monodirectional particles traversing a water phantom. Initial energies ranged from 50 to 250 MeV per nucleon (MeV/A). The following parameters were evaluated: particle range at the distal 80% of maximum energy deposition (Emax), width of the Bragg peak (BP) at 60% of Emax, and dose fall-off width between 80% and 20% of Emax for longitudinal spectra. In addition the fragmentation tail was quantified in terms of length, percental energy deposition, and contributing particles. For each energy lateral profiles were registered along the beam axis and the FWHM at four different depths was extracted. Besides the comparison of parameters between the two particle types, results were also compared to data in the literature. Results: As expected, the position of the BP as a function of initial kinetic energy showed similar values for protons and helium ions, with deviations smaller than 1.3%. The quantitative results of the Monte Carlo (MC) study showed less range straggling effects and smaller lateral deflections for helium ions compared to protons for the investigated energy range. On average, an about 56% reduction of the width of the BP and a 48% reduction of the dose fall-off was observed for helium ions compared to protons. Both the width of the BP and the dose fall-off width as a function of particle range or energy showed an almost linear increase with increasing energy. The tail length increased from 55.9 mm to 592.7 mm and the deposited energy increased from 0.5% to 7.3% for energies between 90 and 250 MeV/A. Lateral profiles of helium ions were about 52% narrower than those of protons. Conclusions: Due to their mass and charge helium ions distinguish themselves from protons in reduced range straggling effects, smaller lateral deflections, and a fragmentation tail. The MC based comprehensive data set for 21 clinically relevant energies can be used to create look-up tables for semi-analytical pencil beam model for helium ions.© 2011.


Langenbeck B.,EBG MedAustron | Siedler C.,EBG MedAustron | Stockner M.,EBG MedAustron | Zickler T.,CERN
IPAC 2011 - 2nd International Particle Accelerator Conference | Year: 2011

MedAustron, a future centre for ion-therapy and research in Austria will comprise an accelerator facility based on a synchrotron for the delivery of protons and light ions for cancer treatment and for clinical and nonclinical research [1]. The main dipole for the synchrotron went through an extensive design process to meet the stringent requirements. The local and integrated field quality was optimized. The residual field levels in the magnet gap were calculated and the dynamic behaviour of the dipole magnet was studied, both in 2D and 3D, using OPERA. The pole profile has been optimized to reduce sextupolar components in the integrated field by adjusting the shims on the pole edge. A Rogowski-profile at the pole ends and the use of stainless-steel tension straps shall enhance the dynamic behaviour and guarantee a small time constants. Appropriate pole-end shimming will be used to compensate for residual multi-pole components and to fine-tune the magnetic length. The results of this comprehensive design study are summarized in this paper. Copyright © 2011 by IPAC'11/EPS-AG.

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