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Böhlen, Till Tobias
Publications (10 of 13) Show all publications
Rescigno, R., Finck, C., Juliani, D., Spiriti, E., Baudot, J., Abou-Haidar, Z., . . . Younis, H. (2014). Performance of the reconstruction algorithms of the FIRST experiment pixel sensors vertex detector. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 767, 34-40
Open this publication in new window or tab >>Performance of the reconstruction algorithms of the FIRST experiment pixel sensors vertex detector
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2014 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 767, p. 34-40Article in journal (Refereed) Published
Abstract [en]

Hadrontherapy treatments use charged particles (e.g. protons and carbon ions) to treat tumors. During a therapeutic treatment with carbon ions, the beam undergoes nuclear fragmentation processes giving rise to significant yields of secondary charged particles. An accurate prediction of these production rates is necessary to estimate precisely the dose deposited into the tumours and the surrounding healthy tissues. Nowadays, a limited set of double differential carbon fragmentation cross-section is available. Experimental data are necessary to benchmark Monte Carlo simulations for their use in hadrontherapy. The purpose of the FIRST experiment is to study nuclear fragmentation processes of ions with kinetic energy in the range from 100 to 1000 MeV/u. Tracks are reconstructed using information from a pixel silicon detector based on the CMOS technology. The performances achieved using this device for hadrontherapy purpose are discussed. For each reconstruction step (clustering, tracking and vertexing), different methods are implemented. The algorithm performances and the accuracy on reconstructed observables are evaluated on the basis of simulated and experimental data.

Keywords
CMOS active pixel sensors, Vertex detector, Clustering, Tracking, Vertexing
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-180044 (URN)10.1016/j.nima.2014.08.024 (DOI)000344994600006 ()
Available from: 2021-11-24 Created: 2021-11-24 Last updated: 2022-03-07Bibliographically approved
Mairani, A., Böhlen, T. T., Schiavi, A., Tessonnier, T., Molinelli, S., Brons, S., . . . Patera, V. (2013). A Monte Carlo-based treatment planning tool for proton therapy. Paper presented at 3rd European Workshop on Monte Carlo Treatment Planning (MCTP), MAY 15-18, 2012, Seville, SPAIN. Physics in Medicine and Biology, 58(8), 2471-2490
Open this publication in new window or tab >>A Monte Carlo-based treatment planning tool for proton therapy
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2013 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 58, no 8, p. 2471-2490Article in journal (Refereed) Published
Abstract [en]

In the field of radiotherapy, Monte Carlo (MC) particle transport calculations are recognized for their superior accuracy in predicting dose and fluence distributions in patient geometries compared to analytical algorithms which are generally used for treatment planning due to their shorter execution times. In this work, a newly developed MC-based treatment planning (MCTP) tool for proton therapy is proposed to support treatment planning studies and research applications. It allows for single-field and simultaneous multiple-field optimization in realistic treatment scenarios and is based on the MC code FLUKA. Relative biological effectiveness (RBE)-weighted dose is optimized either with the common approach using a constant RBE of 1.1 or using a variable RBE according to radiobiological input tables. A validated reimplementation of the local effect model was used in this work to generate radiobiological input tables. Examples of treatment plans in water phantoms and in patient-CT geometries together with an experimental dosimetric validation of the plans are presented for clinical treatment parameters as used at the Italian National Center for Oncological Hadron Therapy. To conclude, a versatile MCTP tool for proton therapy was developed and validated for realistic patient treatment scenarios against dosimetric measurements and commercial analytical TP calculations. It is aimed to be used in future for research and to support treatment planning at state-of-the-art ion beam therapy facilities.

National Category
Radiology, Nuclear Medicine and Medical Imaging Physical Sciences
Identifiers
urn:nbn:se:su:diva-89856 (URN)10.1088/0031-9155/58/8/2471 (DOI)000317185600007 ()23514837 (PubMedID)2-s2.0-84875922059 (Scopus ID)
Conference
3rd European Workshop on Monte Carlo Treatment Planning (MCTP), MAY 15-18, 2012, Seville, SPAIN
Note

AuthorCount:9;

Available from: 2013-05-14 Created: 2013-05-14 Last updated: 2022-10-04Bibliographically approved
Böhlen, T. T., Bauer, J., Dosanjh, M., Ferrari, A., Haberer, T., Parodi, K., . . . Mairani, A. (2013). A Monte Carlo-based treatment-planning tool for ion beam therapy. Journal of radiation research, 54, 77-81
Open this publication in new window or tab >>A Monte Carlo-based treatment-planning tool for ion beam therapy
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2013 (English)In: Journal of radiation research, ISSN 0449-3060, E-ISSN 1349-9157, Vol. 54, p. 77-81Article in journal (Refereed) Published
Abstract [en]

Ion beam therapy, as an emerging radiation therapy modality, requires continuous efforts to develop and improve tools for patient treatment planning (TP) and research applications. Dose and fluence computation algorithms using the Monte Carlo (MC) technique have served for decades as reference tools for accurate dose computations for radiotherapy. In this work, a novel MC-based treatment-planning (MCTP) tool for ion beam therapy using the pencil beam scanning technique is presented. It allows single-field and simultaneous multiple-fields optimization for realistic patient treatment conditions and for dosimetric quality assurance for irradiation conditions at state-of-the-art ion beam therapy facilities. It employs iterative procedures that allow for the optimization of absorbed dose and relative biological effectiveness (RBE)-weighted dose using radiobiological input tables generated by external RBE models. Using a re-implementation of the local effect model (LEM), the MCTP tool is able to perform TP studies using ions with atomic numbers Z < 8. Example treatment plans created with the MCTP tool are presented for carbon ions in comparison with a certified analytical treatment-planning system. Furthermore, the usage of the tool to compute and optimize mixed-ion treatment plans, i.e. plans including pencil beams of ions with different atomic numbers, is demonstrated. The tool is aimed for future use in research applications and to support treatment planning at ion beam facilities.

Keywords
ion beam therapy, treatment planning, Monte Carlo, FLUKA
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:su:diva-92766 (URN)10.1093/jrr/rrt050 (DOI)000321463900011 ()
Note

AuthorCount:8;

Available from: 2013-08-20 Created: 2013-08-20 Last updated: 2022-03-23Bibliographically approved
Sihver, L., Lantz, M., Böhlen, T. T., Mairani, A., Cerutti, A. F. & Ferrari, A. (2012). A comparison of total reaction cross section models used in FLUKA, GEANT4 and PHITS. In: Aerospace Conference, 2012 IEEE. Paper presented at Aerospace Conference, 2012 IEEE (pp. 1-10).
Open this publication in new window or tab >>A comparison of total reaction cross section models used in FLUKA, GEANT4 and PHITS
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2012 (English)In: Aerospace Conference, 2012 IEEE, 2012, p. 1-10Conference paper, Oral presentation only (Refereed)
Abstract [en]

Understanding the interactions and propagations of high energy protons and heavy ions are essential when trying to estimate the biological effects of Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) on personnel on interplanetary missions, and when preparing the construction of a lunar base. To be able to calculate the secondary particles, including neutrons, and to estimate shielding properties of different materials and radiation risks inside complex geometries, particle and heavy ion transport codes are needed. The interactions of the GCR and SPE with matter include many complex properties and many factors influence the calculated results. In all particle and heavy ion transport codes, the probability function that a projectile particle will collide with a nucleus within a certain distance x in the matter depends on the total reaction cross sections, which also scale the calculated partial fragmentation cross sections. It is therefore crucial that accurate total reaction cross section models are used in the transport calculations. FLUKA, GEANT4 and PHITS are three major multi-purpose three-dimensional Monte Carlo particle and heavy ion transport codes widely used for fundamental research, radioprotection, radiotherapy, and space dosimetry. In this paper, a systematic comparison of the total reaction cross section models used as default in these three codes is performed for a variety of systems of importance for space dosimetry, and the need for future improvements and benchmarking against experimental results is discussed. The need for benchmarking and improvements of the partial nuclear reaction and evaporation models, as well as how impact parameter functions, switching time between the dynamical/pre-equilibrium and the de-excitation/evaporation stages, low energy data libraries, etc., influence the final results, is also briefly be discussed.

Keywords
FLUKA;GEANT4;PHITS;biological effect;fundamental research;galactic cosmic ray;heavy ion transport code;heavy ions;high energy protons;interplanetary missions;lunar base;multipurpose 3D Monte Carlo code;partial fragmentation cross section;personnel;radiation risk;radioprotection;radiotherapy;solar particle events;space dosimetry;total reaction cross section model;Moon;aerospace biophysics;biological effects of ionising particles;cosmic rays;dosimetry;
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-81156 (URN)10.1109/AERO.2012.6187014 (DOI)
Conference
Aerospace Conference, 2012 IEEE
Available from: 2012-10-11 Created: 2012-10-11 Last updated: 2022-02-24Bibliographically approved
Mairani, A., Böhlen, T. T., Schiavi, A., Tessonnier, T., Battistoni, G., Parodi, K. & Patera, V. (2012). A Monte Carlo-based treatment planning tool for proton therapy.
Open this publication in new window or tab >>A Monte Carlo-based treatment planning tool for proton therapy
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2012 (English)Manuscript (preprint) (Other academic)
Abstract [en]

In the field of radiotherapy Monte Carlo (MC) particle transport calculations are recognized for their superior accuracy in predicting dose and fluence distributions in patient geometries compared to analytical algorithms which are generally used for treatment planning due to their shorter execution time. In the present work, a newly-developed MC-based treatment planning (MCTP) tool for proton therapy is proposed to support treatment planning studies and research applications. It allows for single-field and simultaneous multiple-field optimization in realistic treatment scenarios and is based on the MC code FLUKA. Relative biological effectiveness (RBE)-weighted dose is optimized either with the common approach using a constant RBE of 1.1 or using a variable RBE according to radiobiological input tables. A validated reimplementation of the local effect model was used in this work to generate radiobiological input tables. Examples of treatment plans in water phantoms and in patient-CT geometries are presented for clinical treatment parameters as used at the CNAO (Italian Center for Hadrontherapy) facility. To conclude, a versatile MCTP tool for proton therapy was developed and validated for realistic patient treatment scenarios and dosimetric measurements. It is aimed to be used in future for research and to support treatment planning at state-of-the-art ion beam therapy facilities.

National Category
Physical Sciences
Research subject
Medical Radiation Physics
Identifiers
urn:nbn:se:su:diva-81165 (URN)
Available from: 2012-10-11 Created: 2012-10-11 Last updated: 2022-02-24Bibliographically approved
Böhlen, T. T., Ferrari, A., Patera, V. & Sala, P. R. (2012). Describing Compton scattering and two-quanta positron annihilation based on Compton profiles: two models suited for the Monte Carlo method. Journal of Instrumentation, 7, P07018
Open this publication in new window or tab >>Describing Compton scattering and two-quanta positron annihilation based on Compton profiles: two models suited for the Monte Carlo method
2012 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 7, p. P07018-Article in journal (Refereed) Published
Abstract [en]

An accurate description of the basic physics processes of Compton scattering and positron annihilation in matter requires the consideration of atomic shell structure effects and, in specific, the momentum distributions of the atomic electrons. Two algorithms which model Compton scattering and two-quanta positron annihilation at rest accounting for shell structure effects are proposed. Two-quanta positron annihilation is a physics process which is of particular importance for applications such as positron emission tomography (PET). Both models use a detailed description of the processes which incorporate consistently Doppler broadening and binding effects. This together with the relatively low level of complexity of the models makes them particularly suited to be employed by fast sampling methods for Monte Carlo particle transport. Momentum distributions of shell electrons are obtained from parametrized one-electron Compton profiles. For conduction electrons, momentum distributions are derived in the framework of a Fermi gas. The Compton scattering model uses an approach which does not employ any free parameter. In contrast, a few semi-empirical approximations are included for the description of the complex physics of electron-positron annihilation resulting in acollinear photons. Comparisons of the Compton scattering model with simpler approaches illustrate the detailed accounting for shell structure effects. A satisfactory agreement is found for comparisons of both newly-developed models with experimental data.

Keywords
Interaction of radiation with matter; Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc); Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA)
National Category
Physical Sciences
Research subject
Medical Radiation Physics
Identifiers
urn:nbn:se:su:diva-81152 (URN)10.1088/1748-0221/7/07/P07018 (DOI)000307076500005 ()
Available from: 2012-10-11 Created: 2012-10-11 Last updated: 2022-03-23Bibliographically approved
Böhlen, T. T., Brons, S., Dosanjh, M., Ferrari, A., Fossati, P., Haberer, T., . . . Mairani, A. (2012). Investigating the robustness of ion beam therapy treatment plans to uncertainties in biological treatment parameters. Physics in Medicine and Biology, 57(23), 7983-8004
Open this publication in new window or tab >>Investigating the robustness of ion beam therapy treatment plans to uncertainties in biological treatment parameters
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2012 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 57, no 23, p. 7983-8004Article in journal (Refereed) Published
Abstract [en]

Uncertainties in determining clinically-used relative biological effectiveness (RBE) values for ion beam therapy carry the risk of absolute and relative misestimations of RBE-weighted doses for clinical scenarios. The present study assesses the consequences of hypothetical misestimations of input parameters to the RBE modelling for carbon ion treatment plans by a variational approach. The impact of the variations on resulting cell survival and RBE values is evaluated as a function of the remaining ion range. In addition, the sensitivity to misestimations in RBE modelling is compared for single fields and two opposed fields using differing optimization criteria. It is demonstrated for single treatment fields that moderate variations (up to ±50%) of representative nominal input parameters for four tumours result mainly in a misestimation of the RBE-weighted dose in the planning target volume (PTV) by a constant factor and only smaller RBE-weighted dose gradients. Ensuring a more uniform radiation quality in the PTV eases the clinical importance of uncertainties in the radiobiological treatment parameters as for such a condition uncertainties tend to result only in a systematic misestimation of RBE-weighted dose in the PTV by a constant factor. Two opposed carbon ion fields with a constant RBE in the PTV are found to result in rather robust conditions. Treatments using two ion species may be used to achieve a constant RBE in the PTV irrespective of the size and depth of the spread-out Bragg peak.

National Category
Physical Sciences
Research subject
Medical Radiation Physics
Identifiers
urn:nbn:se:su:diva-81164 (URN)10.1088/0031-9155/57/23/7983 (DOI)000311351400022 ()23154750 (PubMedID)2-s2.0-84870342065 (Scopus ID)
Available from: 2012-10-11 Created: 2012-10-11 Last updated: 2022-10-03Bibliographically approved
Böhlen, T. T. (2012). Monte Carlo particle transport codes for ion beam therapy treatment planning: Validation, development and applications. (Doctoral dissertation). Stockholm: Department of Physics, Stockholm University
Open this publication in new window or tab >>Monte Carlo particle transport codes for ion beam therapy treatment planning: Validation, development and applications
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

External radiotherapy with proton and ion beams needs accurate tools for the dosimetric characterization of treatment fields. Monte Carlo (MC) particle transport codes, such as FLUKA and GEANT4, can be a valuable method to increase accuracy of dose calculations and to support various aspects of ion beam therapy (IBT), such as treatment planning and monitoring. One of the prerequisites for such applications is however that the MC codes are able to model reliably and accurately the relevant physics processes. As a first focus of this thesis work, physics models of MC codes with importance for IBT are developed and validated with experimental data. As a result suitable models and code configurations for applications in IBT are established. The accuracy of FLUKA and GEANT4 in describing nuclear fragmentation processes and the production of secondary charged nuclear fragments is investigated for carbon ion therapy. As a complementary approach to evaluate the capability of FLUKA to describe the characteristics of mixed radiation fields created by ion beams, simulated microdosimetric quantities are compared with experimental data. The correct description of microdosimetric quantities is also important when they are used to predict values of relative biological effectiveness (RBE). Furthermore, two models describing Compton scattering and the acollinearity of two-quanta positron annihilation at rest in media were developed, validated and integrated in FLUKA. The detailed description of these processes is important for an accurate simulation of positron emission tomography (PET) and prompt-γ imaging. Both techniques are candidates to be used in clinical routine to monitor dose administration during cancer treatments with IBT. The second objective of this thesis is to contribute to the development of a MC-based treatment planning tool for protons and ions with atomic number Z ≤ 8 using FLUKA. In contrast to previous clinical FLUKA-based MC implementations for IBT which only re-calculate a given treatment plan, the developed prototype features inverse optimization of absorbed dose and RBE-weighted dose for single fields and simultaneous multiple-field optimization for realistic treatment conditions. In a study using this newly-developed tool, the robustness of IBT treatment fields to uncertainties in the prediction of RBE values is investigated, while comparing different optimization strategies.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2012. p. 86
Keywords
Monte Carlo, ion beam therapy, treatment planning, cancer therapy, microdosimetry
National Category
Physical Sciences
Research subject
Medical Radiation Physics
Identifiers
urn:nbn:se:su:diva-81111 (URN)978-91-7447-551-7 (ISBN)
Public defence
2012-11-29, föreläsningssalen, Radiumhemmet, Karolinska universitetssjukhuset, Solna, 09:00 (English)
Opponent
Supervisors
Funder
EU, FP7, Seventh Framework Programme, PITN-GA-2008-215840-PARTNEREU, FP7, Seventh Framework Programme, ENVISION FP7 Grant Agreement N. 241851
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Submitted. Paper 6: Manuscript.

Available from: 2012-11-07 Created: 2012-10-10 Last updated: 2022-02-24Bibliographically approved
Böhlen, T. T., Dosanjh, M., Ferrari, A. & Gudowska, I. (2012). Simulations of microdosimetric quantities with the Monte Carlo code FLUKA for carbon ions at therapeutic energies. International Journal of Radiation Biology, 88(1-2), 176-182
Open this publication in new window or tab >>Simulations of microdosimetric quantities with the Monte Carlo code FLUKA for carbon ions at therapeutic energies
2012 (English)In: International Journal of Radiation Biology, ISSN 0955-3002, E-ISSN 1362-3095, Vol. 88, no 1-2, p. 176-182Article in journal (Refereed) Published
Abstract [en]

Purpose: Microdosimetric quantities can be used to estimate the biological effectiveness of radiation fields. This study evaluates the capability of the general-purpose Monte Carlo code FLUKA to simulate microscopic patterns of energy depositions for mixed radiation fields which are created by carbon ions at therapeutic energies in phantoms. Materials and methods: Measured lineal energy spectra and linear energy transfer (LET) spectra produced by carbon ions of about 300 MeV/n at different depths in phantoms representing human tissue were chosen from published literature and were compared with results from simulations of the measurement set-ups with FLUKA. Results: Simulations of the dose-weighted lineal energy spectra yd(y) and dose-weighted LET spectra describe the main features of the respective measured spectra. All simulated frequency mean and dose mean lineal energy values are, respectively, within 21% and 11% of the measured ones. A slight underestimation of fragment fluences is notable. It is shown that the simultaneous detection of several charged fragments in the TEPC ('V effect') has considerable impact on the measured lineal energy spectra of fragments. Conclusions: Agreement between measurements and FLUKA results is encouraging and shows that FLUKA can predict microdosimetric spectra of mixed radiation fields created by therapeutic carbon ions in phantoms reasonably well.

Keywords
Monte Carlo; FLUKA; hadron therapy; carbon ion; microdosimetry; benchmarking
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-81155 (URN)10.3109/09553002.2011.620062 (DOI)000298666000028 ()21913815 (PubMedID)2-s2.0-84855373803 (Scopus ID)
Available from: 2012-10-11 Created: 2012-10-11 Last updated: 2022-10-03Bibliographically approved
Pleskac, R., Abou-Haidar, Z., Agodi, C., Alvarez, M. A., Aumann, T., Battistoni, G., . . . Patera, V. (2012). The FIRST experiment at GSI. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 678, 130-138
Open this publication in new window or tab >>The FIRST experiment at GSI
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2012 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 678, p. 130-138Article in journal (Refereed) Published
Abstract [en]

The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at the SIS accelerator of GSl laboratory in Darmstadt has been designed for the measurement of ion fragmentation crosssections at different angles and energies between 100 and 1000 MeV/nucleon. Nuclear fragmentation processes are relevant in several fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The start of the scientific program of the FIRST experiment was on summer 2011 and was focused on the measurement of 400 MeV/nucleon C-12 beam fragmentation on thin (8 mm) graphite target. The detector is partly based on an already existing setup made of a dipole magnet (ALADiN). a time projection chamber (TP-MUSIC IV), a neutron detector (LAND) and a time of flight scintillator system (TOFWALL). This pre-existing setup has been integrated with newly designed detectors in the Interaction Region, around the carbon target placed in a sample changer. The new detectors are a scintillator Start Counter, a Beam Monitor drift chamber, a silicon Vertex Detector and a Proton Tagger scintillator system optimized for the detection of light fragments emitted at large angles. In this paper we review the experimental setup, then we present the simulation software, the data acquisition system and finally the trigger strategy of the experiment.

Keywords
Hadrontherapy, Fragmentation, Nuclear physics, Elementary-particle, Experimental methods, Instrumentation
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-80017 (URN)10.1016/j.nima.2012.02.020 (DOI)000304503300018 ()2-s2.0-84859698703 (Scopus ID)
Note

AuthorCount:57;

Available from: 2012-09-12 Created: 2012-09-12 Last updated: 2022-10-04Bibliographically approved
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