The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Anatoly B. Rosenfeld - One of the best experts on this subject based on the ideXlab platform.
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evolution of diamond based Microdosimetry
Journal of Physics: Conference Series, 2019Co-Authors: Jeremy A Davis, Marco Petasecca, Susanna Guatelli, Michael L. F Lerch, Anatoly B. RosenfeldAbstract:The requirements for solid state micro- dosimetry particularly within the context of medical and space environments necessitate a tissue equivalent and radiation hard material, for which diamond is uniquely suited. An overview of the current status of diamond based Microdosimetry is given. This overview will explore previous and current technologies developed by the Centre for Medical Radiation Physics (CMRP). The overview will analyse technologies in terms of their advantages and disadvantages within the context of Microdosimetry. Using this as a basis, recommendations with respect to fabri- cation methodologies/techniques are provided in order to direct the course and progress of development so as to achieve true diamond based Microdosimetry.
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novel detectors for silicon based Microdosimetry their concepts and applications
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2016Co-Authors: Anatoly B. RosenfeldAbstract:Abstract This paper presents an overview of the development of semiconductor Microdosimetry and the most current (state-of-the-art) Silicon on Insulator (SOI) detectors for Microdosimetry based mainly on research and development carried out at the Centre for Medical Radiation Physics (CMRP) at the University of Wollongong with collaborators over the last 18 years. In this paper every generation of CMRP SOI microdosimeters, including their fabrication, design, and electrical and charge collection characterisation are presented. A study of SOI microdosimeters in various radiation fields has demonstrated that under appropriate geometrical scaling, the response of SOI detectors with the well-known geometry of microscopically sensitive volumes will record the energy deposition spectra representative of tissue cells of an equivalent shape. This development of SOI detectors for Microdosimetry with increased complexity has improved the definition of microscopic sensitive volume (SV), which is modelling the deposition of ionising energy in a biological cell, that are led from planar to 3D SOI detectors with an array of segmented microscopic 3D SVs. The monolithic ΔE−E silicon telescope, which is an alternative to the SOI silicon microdosimeter, is presented, and as an example, applications of SOI detectors and ΔE−E monolithic telescope for microdosimetery in proton therapy field and equivalent neutron dose measurements out of field are also presented. An SOI microdosimeter “bridge” with 3D SVs can derive the relative biological effectiveness (RBE) in 12C ion radiation therapy that matches the tissue equivalent proportional counter (TEPC) quite well, but with outstanding spatial resolution. The use of SOI technology in experimental Microdosimetry offers simplicity (no gas system or HV supply), high spatial resolution, low cost, high count rates, and the possibility of integrating the system onto a single device with other types of detectors.
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study of a monolithic silicon telescope for solid state Microdosimetry response to a 100 mev proton beam
Faculty of Engineering - Papers (Archive), 2011Co-Authors: Anatoly B. Rosenfeld, S Agosteo, A Fazzi, M V Introini, A Pola, R ShulteAbstract:Abstract A monolithic silicon telescope was recently proposed and studied for solid state Microdosimetry. It consists of a thin surface ∆E stage (about 2 μm in thickness), at study for silicon Microdosimetry, coupled to an E stage about 500 μm in thickness, which provide information about the energy of the impinging particle. In order to study the response of the detection system to high energy charged hadrons, the silicon telescope was placed in a polystyrene phantom and irradiated with a 100 MeV un-modulated proton beam at the Loma Linda University Medical Centre. The experimental results were compared with those obtained with a numerical study based on Monte Carlo simulations carried out with the FLUKA code. The agreement between experimental and simulation results was satisfactory.
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solid state Microdosimetry with heavy ions for space applications
IEEE Transactions on Nuclear Science, 2007Co-Authors: A Wroe, Anatoly B. Rosenfeld, Marco Zaider, M I Reinhard, V L Pisacane, J F Ziegler, M E Nelson, F Cucinotta, J F DicelloAbstract:This work provides information pertaining to the performance of Silicon-On-Insulator (SOI) microdosimeters in heavy ion radiation fields. SOI microdosimeters have been previously tested in light ion radiation fields for both space and therapeutic applications, however their response has not been established in high energy, heavy ion radiation fields which are experienced in space. Irradiations were completed at the NASA Space Radiation Laboratory at BNL using 0.6 GeV/u Fe and 1.0 GeV/u Ti ions. Energy deposition and lineal energy spectra were obtained with this device at various depths within a Lucite phantom along the central axis of the beam. The response of which was compared with existing proportional counter data to assess the applicability of SOI microdosimeters to future deployments in space missions.
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a cylindrical silicon on insulator microdosimeter charge collection characteristics
IEEE Nuclear Science Symposium, 2007Co-Authors: A L Ziebell, Dale A. Prokopovich, Iwan Cornelius, W H Lim, M I Reinhard, Rainer Siegele, A S Dzurak, Anatoly B. RosenfeldAbstract:This study introduces and investigates a new silicon-on-insulator (SOI) microdosimeter with an array of 3D cylindrical micron sized sensitive volumes (SVs) for use in calculating the radiobiological effectiveness (RBE) of a radiation field via the Microdosimetry approach. An ion beam induced charge (IBIC) study of individual SVs has revealed a well defined truly micron sized SV with a near 100 % charge collection efficiency (CCE). By eliminating cross talk between individual SVs, the device has the capability of studying the track structure of high energy, heavy ions like those found in a deep space environment.
Marco Zaider - One of the best experts on this subject based on the ideXlab platform.
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solid state Microdosimetry with heavy ions for space applications
IEEE Transactions on Nuclear Science, 2007Co-Authors: A Wroe, Anatoly B. Rosenfeld, Marco Zaider, M I Reinhard, V L Pisacane, J F Ziegler, M E Nelson, F Cucinotta, J F DicelloAbstract:This work provides information pertaining to the performance of Silicon-On-Insulator (SOI) microdosimeters in heavy ion radiation fields. SOI microdosimeters have been previously tested in light ion radiation fields for both space and therapeutic applications, however their response has not been established in high energy, heavy ion radiation fields which are experienced in space. Irradiations were completed at the NASA Space Radiation Laboratory at BNL using 0.6 GeV/u Fe and 1.0 GeV/u Ti ions. Energy deposition and lineal energy spectra were obtained with this device at various depths within a Lucite phantom along the central axis of the beam. The response of which was compared with existing proportional counter data to assess the applicability of SOI microdosimeters to future deployments in space missions.
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miniature semiconductor detectors for in vivo dosimetry
Radiation Protection Dosimetry, 2006Co-Authors: Anatoly B. Rosenfeld, Michael L. F Lerch, Dean L Cutajar, George J Takacs, Iwan Cornelius, M Yudelev, Marco ZaiderAbstract:Silicon mini-semiconductor detectors are found in wide applications for in vivo personal dosimetry and dosimetry and Microdosimetry of different radiation oncology modalities. These applications are based on integral and spectroscopy modes of metal oxide semiconductor field effect transistor and silicon p-n junction detectors. The advantages and limitations of each are discussed.
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Microdosimetry simulations of solar protons within a spacecraft
IEEE Transactions on Nuclear Science, 2005Co-Authors: A Wroe, Anatoly B. Rosenfeld, Marco Zaider, Iwan Cornelius, V L Pisacane, J F Ziegler, M E Nelson, Francis A Cucinotta, J F DicelloAbstract:The microdosimetric spectra derived by silicon microdosimeter in a proton radiation field traversing heterogeneous structures were simulated using the GEANT4 toolkit.
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solid state Microdosimetry in hadron therapy
Radiation Protection Dosimetry, 2002Co-Authors: A B Rosenfled, P. D. Bradley, R L Maughan, Marco Zaider, Iwan Cornelius, Barry Allen, J C Yanch, J Flanz, T KobayashiAbstract:A report of recent developments in silicon Microdosimetry is presented. SOI based microdosemeters have shown promise as a viable alternative to traditional tissue-equivalent proportional counters. The application of these silicon microdosemeters to such radiation therapy modalities as boron neutron capture therapy (BNCT), boron neutron capture synovectomy (BNCS), proton therapy (PT), and fast neutron therapy (FNT) has been performed. Several shortcomings of the current silicon microdose-meter were identified and will be taken into account in the design of a second-generation device.
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solid state Microdosimetry
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2001Co-Authors: P. D. Bradley, Anatoly B. Rosenfeld, Marco ZaiderAbstract:A review of solid state Microdosimetry is presented with an emphasis on silicon-based devices. The historical foundations and basics of Microdosimetry are briefly provided. Various methods of experimental regional Microdosimetry are discussed to facilitate a comparison with the more recent development of silicon Microdosimetry. In particular, the performance characteristics of a proportional gas counter and a silicon microdosimeter are compared. Recent improvements in silicon Microdosimetry address the issues of requirement specification, non-spherical shape, tissue equivalence, sensitive volume definition (charge collection complexity) and low noise requirements which have previously impeded the implementation of silicon-based Microdosimetry. A prototype based on silicon-on-insulator technology is described along with some example results from clinical high LET radiotherapy facilities. A brief summary of the applications of Microdosimetry is included.
P. D. Bradley - One of the best experts on this subject based on the ideXlab platform.
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solid state Microdosimetry in hadron therapy
Radiation Protection Dosimetry, 2002Co-Authors: A B Rosenfled, P. D. Bradley, R L Maughan, Marco Zaider, Iwan Cornelius, Barry Allen, J C Yanch, J Flanz, T KobayashiAbstract:A report of recent developments in silicon Microdosimetry is presented. SOI based microdosemeters have shown promise as a viable alternative to traditional tissue-equivalent proportional counters. The application of these silicon microdosemeters to such radiation therapy modalities as boron neutron capture therapy (BNCT), boron neutron capture synovectomy (BNCS), proton therapy (PT), and fast neutron therapy (FNT) has been performed. Several shortcomings of the current silicon microdose-meter were identified and will be taken into account in the design of a second-generation device.
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solid state Microdosimetry
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2001Co-Authors: P. D. Bradley, Anatoly B. Rosenfeld, Marco ZaiderAbstract:A review of solid state Microdosimetry is presented with an emphasis on silicon-based devices. The historical foundations and basics of Microdosimetry are briefly provided. Various methods of experimental regional Microdosimetry are discussed to facilitate a comparison with the more recent development of silicon Microdosimetry. In particular, the performance characteristics of a proportional gas counter and a silicon microdosimeter are compared. Recent improvements in silicon Microdosimetry address the issues of requirement specification, non-spherical shape, tissue equivalence, sensitive volume definition (charge collection complexity) and low noise requirements which have previously impeded the implementation of silicon-based Microdosimetry. A prototype based on silicon-on-insulator technology is described along with some example results from clinical high LET radiotherapy facilities. A brief summary of the applications of Microdosimetry is included.
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a new silicon detector for Microdosimetry applications in proton therapy
Nuclear Science Symposium and Medical Imaging Conference, 1999Co-Authors: Anatoly B. Rosenfeld, P. D. Bradley, Iwan Cornelius, Barry Allen, J Flanz, G I Kaplan, M Goitein, A Van Meerbeeck, J Schubert, J BaileyAbstract:A silicon-on-insulator diode array with a sensitive depth of 10 microns has been developed for Microdosimetry in proton therapy. The detector was coupled to a radiation-hard charge sensitive amplifier with the probe assembly capable of measuring an LET down to 1.2 keV//spl mu/m. The device has been successfully tested at two proton therapy centers. The 230 MeV Northeastern Proton Therapy Center, Boston and the 250 MeV Proton Medical Research Center at Tsukuba, Japan. The device offers much improved spatial resolution compared with a proportional gas counter particularly in the critical high dose region around the proton Bragg peak. Due to its small cross-sectional area (0.04 cm/sup 2/) measurements may also be made in facilities with short high intensity beams.
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performance of silicon Microdosimetry detectors in boron neutron capture therapy
Radiation Research, 1999Co-Authors: P. D. Bradley, Anatoly B. Rosenfeld, Barry Allen, Jeffrey A Coderre, Jacek CapalaAbstract:Reverse-biased silicon p-n junction arrays using Silicon-On-Insulator technology have been proposed as microdosimeters. The performance of such detectors in boron neutron capture therapy (BNCT) is discussed. This work provides the first reported measurements using boron-coated silicon diode arrays as microdosimeters in BNCT. Results are in good agreement with measurements with gas proportional counters. Various boron-coating options are investigated along with device orientation effects. Finally, a 235 U coating is tested to simulate the behavior of the device in a heavy-ion therapy beam.
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Semiconductor Microdosimetry in mixed radiation and photon fields: Present and future
Radiation Protection Dosimetry, 1999Co-Authors: Anatoly B. Rosenfeld, P. D. BradleyAbstract:A new approach to Microdosimetry based on a silicon on insulator (SOI) p-n junction array has been offered for use in radiation oncology and a prototype has been tested in fast neutron therapy (FNT), boron neutron capture therapy (BNCT) and proton therapy. The advantages of the new microdosemeter are its small size, simple conversion of measured amplitude spectra to tissue-equivalent microdosimetric spectra and the possibility of incorporating the sensitive element and readout electronics on the same chip. Such a microdosemeter could also be attractive for equivalent dose monitoring in personal radiation protection dosimetry.
S Agosteo - One of the best experts on this subject based on the ideXlab platform.
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Microdosimetry of a therapeutic proton beam with a mini tepc and a microplus bridge detector for rbe assessment
Physics in Medicine and Biology, 2020Co-Authors: V Conte, P Colautti, David Bolst, S Agosteo, D Bortot, A M Bianchi, Roberto Catalano, G A P Cirrone, G Cuttone, Susanna GuatelliAbstract:Proton beams are widely used worldwide to treat localized tumours, the lower entrance dose and no exit dose, thus sparing surrounding normal tissues, being the main advantage of this treatment modality compared to conventional photon techniques. Clinical proton beam therapy treatment planning is based on the use of a general relative biological effectiveness (RBE) of 1.1 along the whole beam penetration depth, without taking into account the documented increase in RBE at the end of the depth dose profile, in the Bragg peak and beyond. However, an inaccurate estimation of the RBE can cause both underdose or overdose, in particular it can cause the unfavourable situation of underdosing the tumour and overdosing the normal tissue just beyond the tumour, which limits the treatment success and increases the risk of complications. In view of a more precise dose delivery that takes into account the variation of RBE, experimental Microdosimetry offers valuable tools for the quality assurance of LET or RBE-based treatment planning systems. The purpose of this work is to compare the response of two different Microdosimetry systems: the mini-TEPC and the MicroPlus-Bridge detector. Microdosimetric spectra were measured across the 62 MeV spread out Bragg peak of CATANA with the mini-TEPC and with the Bridge microdosimeter. The frequency and dose distributions of lineal energy were compared and the different contributions to the spectra were analysed, discussing the effects of different site sizes and chord length distributions. The shape of the lineal energy distributions measured with the two detectors are markedly different, due to the different water-equivalent sizes of the sensitive volumes: 0.85 μm for the TEPC and 17.3 μm for the silicon detector. When the Loncol's biological weighting function is applied to calculate the microdosimetric assessment of the RBE, both detectors lead to results that are consistent with biological survival data for glioma U87 cells. Both the mini-TEPC and the MicroPlus-Bridge detector can be used to assess the RBE variation of a 62 MeV modulated proton beam along its penetration depth. The microdosimetric assessment of the RBE based on the Loncol's weighting function is in good agreement with radiobiological results when the 10% biological uncertainty is taken into account.
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Microdosimetry at nanometric scale with an avalanche confinement tepc response against a helium ion beam
Radiation Protection Dosimetry, 2019Co-Authors: D Mazzucconi, V Conte, P Colautti, S Agosteo, A Fazzi, A Pola, D Bortot, Stefano Pasquato, G Petringa, A G AmicoAbstract:The tissue-equivalent proportional counter (TEPC) is the most accurate device for measuring the microdosimetric properties of a particle beam but, since the lower operation limit of common TEPCs is ~0.3 μm, no detailed information on the track structure of the impinging particles can be obtained. The pattern of particle interactions at the nanometric level is measured directly by only three different nanodosimeters worldwide: practical instruments are not yet available. In order to partially fill the gap between Microdosimetry and track-nanodosimetry, a low-pressure avalanche-confinement TEPC was designed and constructed for simulating tissue-equivalent sites down to the nanometric region. The present paper aims at describing the response of this TEPC in the range 0.3 μm-25 nm to a 62 MeV/n 4He ion beam. The experimental results, for depths near the Bragg peak, show good agreement with FLUKA simulations and suggest that, for smaller depths, the distribution is highly influenced by secondary electrons.
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a novel tepc for Microdosimetry at nanometric level response against different neutron fields
Radiation Protection Dosimetry, 2018Co-Authors: D Bortot, S Agosteo, A Fazzi, A Pola, Stefano Pasquato, D Mazzucconi, Matteo Bonfanti, P ColauttiAbstract:Tissue equivalent proportional counter (TEPC) is the most accurate device for measuring the microdosimetric properties of a particle beam, nevertheless no detailed information on the track structure of the impinging particles can be obtained, since the lower operation limit of common TEPCs is ~0.3 μm. On the other hand, the pattern of particle interactions at the nanometer level is measured by only three different nanodosimeters worldwide: practical instruments are not yet available. In order to partially fill the gap between Microdosimetry and track-nanodosimetry, a low-pressure avalanche-confinement TEPC was recently designed and constructed for simulating tissue-equivalent sites down to the nanometric region. The present article aims at describing the response of this newly developed TEPC in the range 0.3 μm-25 nm against a fast neutron field from a 241Am-Be source and a quasi-monoenergetic neutron beam. The experimental results are in good agreement with Monte Carlo simulations carried out with the FLUKA code.
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a novel avalanche confinement tepc for Microdosimetry at nanometric level
Radiation Measurements, 2017Co-Authors: S Agosteo, A Pola, D Bortot, Stefano Pasquato, D MazzucconiAbstract:Abstract The tissue equivalent proportional counter (TEPC) is the most accurate device for measuring the microdosimetric properties of a particle beam, showing to assess the relative biological effectiveness by linking the physical parameters of the radiation field with the corresponding biological response. Nevertheless, no detailed information on the track structure of the impinging particles can be obtained, since the lower operation limit of the common TEPCs is about 0.3 μm. On the other hand, the pattern of particle interactions at the nanometer level, which demonstrated to have a strong correlation with radiation-induced damages to the DNA, is measured directly by only three different nanodosimeters worldwide: practical instruments are not yet available. The gap between Microdosimetry and track-nanodosimetry can be filled partially by extending the TEPC response down to the nanometric region. A feasibility study of a novel TEPC designed to simulate tissue-equivalent sites in the nanometric domain was performed. The present paper aims at describing the design, the development and the characterization of this avalanche-confinement TEPC. Irradiations with photons, fast neutrons and low-energy carbon ions demonstrated the capability of this TEPC of measuring in the range 0.3 μm–25 nm.
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study of a monolithic silicon telescope for solid state Microdosimetry response to a 100 mev proton beam
Faculty of Engineering - Papers (Archive), 2011Co-Authors: Anatoly B. Rosenfeld, S Agosteo, A Fazzi, M V Introini, A Pola, R ShulteAbstract:Abstract A monolithic silicon telescope was recently proposed and studied for solid state Microdosimetry. It consists of a thin surface ∆E stage (about 2 μm in thickness), at study for silicon Microdosimetry, coupled to an E stage about 500 μm in thickness, which provide information about the energy of the impinging particle. In order to study the response of the detection system to high energy charged hadrons, the silicon telescope was placed in a polystyrene phantom and irradiated with a 100 MeV un-modulated proton beam at the Loma Linda University Medical Centre. The experimental results were compared with those obtained with a numerical study based on Monte Carlo simulations carried out with the FLUKA code. The agreement between experimental and simulation results was satisfactory.
Susanna Guatelli - One of the best experts on this subject based on the ideXlab platform.
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Microdosimetry of a therapeutic proton beam with a mini tepc and a microplus bridge detector for rbe assessment
Physics in Medicine and Biology, 2020Co-Authors: V Conte, P Colautti, David Bolst, S Agosteo, D Bortot, A M Bianchi, Roberto Catalano, G A P Cirrone, G Cuttone, Susanna GuatelliAbstract:Proton beams are widely used worldwide to treat localized tumours, the lower entrance dose and no exit dose, thus sparing surrounding normal tissues, being the main advantage of this treatment modality compared to conventional photon techniques. Clinical proton beam therapy treatment planning is based on the use of a general relative biological effectiveness (RBE) of 1.1 along the whole beam penetration depth, without taking into account the documented increase in RBE at the end of the depth dose profile, in the Bragg peak and beyond. However, an inaccurate estimation of the RBE can cause both underdose or overdose, in particular it can cause the unfavourable situation of underdosing the tumour and overdosing the normal tissue just beyond the tumour, which limits the treatment success and increases the risk of complications. In view of a more precise dose delivery that takes into account the variation of RBE, experimental Microdosimetry offers valuable tools for the quality assurance of LET or RBE-based treatment planning systems. The purpose of this work is to compare the response of two different Microdosimetry systems: the mini-TEPC and the MicroPlus-Bridge detector. Microdosimetric spectra were measured across the 62 MeV spread out Bragg peak of CATANA with the mini-TEPC and with the Bridge microdosimeter. The frequency and dose distributions of lineal energy were compared and the different contributions to the spectra were analysed, discussing the effects of different site sizes and chord length distributions. The shape of the lineal energy distributions measured with the two detectors are markedly different, due to the different water-equivalent sizes of the sensitive volumes: 0.85 μm for the TEPC and 17.3 μm for the silicon detector. When the Loncol's biological weighting function is applied to calculate the microdosimetric assessment of the RBE, both detectors lead to results that are consistent with biological survival data for glioma U87 cells. Both the mini-TEPC and the MicroPlus-Bridge detector can be used to assess the RBE variation of a 62 MeV modulated proton beam along its penetration depth. The microdosimetric assessment of the RBE based on the Loncol's weighting function is in good agreement with radiobiological results when the 10% biological uncertainty is taken into account.
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evolution of diamond based Microdosimetry
Journal of Physics: Conference Series, 2019Co-Authors: Jeremy A Davis, Marco Petasecca, Susanna Guatelli, Michael L. F Lerch, Anatoly B. RosenfeldAbstract:The requirements for solid state micro- dosimetry particularly within the context of medical and space environments necessitate a tissue equivalent and radiation hard material, for which diamond is uniquely suited. An overview of the current status of diamond based Microdosimetry is given. This overview will explore previous and current technologies developed by the Centre for Medical Radiation Physics (CMRP). The overview will analyse technologies in terms of their advantages and disadvantages within the context of Microdosimetry. Using this as a basis, recommendations with respect to fabri- cation methodologies/techniques are provided in order to direct the course and progress of development so as to achieve true diamond based Microdosimetry.
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soi Microdosimetry and modified mkm for evaluation of relative biological effectiveness for a passive proton therapy radiation field
Physics in Medicine and Biology, 2018Co-Authors: Emily Debrot, David Bolst, Linh T. Tran, Lachlan Chartier, Susanna Guatelli, Charlot Vandevoorde, E De Kock, P Beukes, J Symons, Jaime NietocameroAbstract:With more patients receiving external beam radiation therapy with protons, it becomes increasingly important to refine the clinical understanding of the relative biological effectiveness (RBE) for dose delivered during treatment. Treatment planning systems used in clinics typically implement a constant RBE of 1.1 for proton fields irrespective of their highly heterogeneous linear energy transfer (LET). Quality assurance tools that can measure beam characteristics and quantify or be indicative of biological outcomes become necessary in the transition towards more sophisticated RBE weighted treatment planning and for verification of the Monte Carlo and analytical based models they use. In this study the RBE for the CHO-K1 cell line in a passively delivered clinical proton spread out Bragg peak (SOBP) is determined both in vitro and using a silicon-on-insulator (SOI) Microdosimetry method paired with the modified microdosimetric kinetic model. The RBE along the central axis of a SOBP with 2 Gy delivered at the middle of the treatment field was found to vary between 1.11-1.98 and the RBE for 10% cell survival between 1.07-1.58 with a 250 kVp x-ray reference radiation and between 1.19-2.34 and 0.95-1.41, respectively, for a Co60 reference. Good agreement was found between RBE values calculated from the SOI-Microdosimetry-MKM approach and in vitro. A strong correlation between proton lineal energy and RBE was observed particularly in the distal end and falloff of the SOBP.
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Microdosimetry of electrons in liquid water using the low energy models of geant4
Journal of Applied Physics, 2017Co-Authors: Ioanna Kyriakou, Susanna Guatelli, Dimitris Emfietzoglou, V Ivanchenko, M C Bordage, Peter Lazarakis, H N Tran, S IncertiAbstract:The biological effects of ionizing radiation at the cellular level are frequently studied using the well-known formalism of Microdosimetry, which provides a quantitative description of the stochastic aspects of energy deposition in irradiated media. Energy deposition can be simulated using Monte Carlo codes, some adopting a computationally efficient condensed-history approach, while others follow a more detailed track-structure approach. In this work, we present the simulation of Microdosimetry spectra and related quantities (frequency-mean and dose-mean lineal energies) for incident monoenergetic electrons (50 eV–10 keV) in spheres of liquid water with dimensions comparable to the size of biological targets: base pairs (2 nm diameter), nucleosomes (10 nm), chromatin fibres (30 nm) and chromosomes (300 nm). Simulations are performed using the condensed-history low-energy physics models (“Livermore” and “Penelope”) and the track-structure Geant4-DNA physics models, available in the Geant4 Monte Carlo simul...
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RBE study using solid state Microdosimetry in heavy ion therapy
Radiation Measurements, 2017Co-Authors: David Bolst, Linh T. Tran, Lachlan Chartier, Dale A. Prokopovich, Alex Pogossov, Susanna Guatelli, Mark I. Reinhard, Marco Petasecca, Michael L. F Lerch, Naruhiro MatsufujiAbstract:Abstract The response of two types of 10 μm thick silicon-on-insulator (SOI) detectors in a 12 C ion therapy beam with extremely high spatial resolution are presented in this work. The two detectors used are the “bridge” microdosimeter with isolated 3D sensitive volumes (SVs) and the ultra-thin 3D (U3DTHIN) detector with n + and p + 3D columnar structures. Both detectors were investigated at various depths in a water phantom along the central axis of the spread-out Brag peak (SOBP) of a 290 MeV/u 12 C ion beam at the Heavy Ion Medical Accelerator in Chiba, Japan. Based on the Microdosimetric Kinetic (MK) model and the microdosimetric quantities measured with the two detectors, the relative biological effectiveness (RBE) values were derived and compared to results obtained with the tissue-equivalent proportional counter (TEPC). Derived RBE 10 values obtained with the U3DTHIN detector were considerably higher than those obtained with the bridge microdosimeter and the TEPC along the SOBP. Due to the high spatial resolution of the microdosimeters, more detailed measurements were obtained at the end of the SOBP compared to the TEPC. The maximum derived RBE 10 found using the U3DTHIN detector and bridge microdosimeter were approximately 2.66 and 2.58, respectively which are higher than the RBE 10 value of 2.35 obtained with the TEPC due to the lack of high spatial resolution in the TEPC. The discrepancy in the results obtained using the two detectors is due to the difference in geometry of the SVs in the two detectors. This work presents an application of different types of SOI micodosimeters in a 12 C ion therapy beam and has demonstrated that the microdosimeter with micron sized 3D SVs is more desirable for accurate lineal energy measurement and RBE determination. Silicon Microdosimetry has demonstrated a simple, fast and accurate method for routine Quality Assurance in charged particle therapy.