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Olivari F, van Goethem MJ, Brandenburg S, van der Graaf ER. A Monte-Carlo-based study of a single-2D-detector proton-radiography system. Phys Med 2023; 112:102636. [PMID: 37494764 DOI: 10.1016/j.ejmp.2023.102636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 05/14/2023] [Accepted: 07/04/2023] [Indexed: 07/28/2023] Open
Abstract
PURPOSE To assess the feasibility of a proton radiography (pRG) system based on a single thin pixelated detector for water-equivalent path length (WEPL) and relative stopping power (RSP) measurements. METHODS A model of a pRG system consisting of a single pixelated detector measuring energy deposition and proton fluence was investigated in a Geant4-based Monte Carlo study. At the position directly after an object traversed by a broad proton beam, spatial 2D distributions are calculated of the energy deposition in, and the number of protons entering the detector. Their ratio relates to the 2D distribution of the average stopping power of protons in the detector. The system response is calibrated against the residual range in water of the protons to provide the 2D distribution of the WEPL of the object. The WEPL distribution is converted into the distribution of the RSP of the object. Simulations have been done, where the system has been tested on 13 samples of homogeneous materials of which the RSPs have been calculated and compared with RSPs determined from simulations of residual-range-in-water, which we refer to as reference RSPs. RESULTS For both human-tissue- and non-human-tissue-equivalent materials, the RSPs derived with the detector agree with the reference values within 1%. CONCLUSION The study shows that a pRG system based on one thin pixelated detection screen has the potential to provide RSP predictions with an accuracy of 1%.
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Affiliation(s)
- Francesco Olivari
- Department of Radiation Oncology, University Medical Center Groningen (UMCG), University of Groningen (RUG), Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
| | - Marc-Jan van Goethem
- Department of Radiation Oncology, University Medical Center Groningen (UMCG), University of Groningen (RUG), Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Sytze Brandenburg
- Department of Radiation Oncology, University Medical Center Groningen (UMCG), University of Groningen (RUG), Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Emiel R van der Graaf
- Department of Radiation Oncology, University Medical Center Groningen (UMCG), University of Groningen (RUG), Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
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Kretschmer J, Brodbek L, Looe HK, van der Graaf E, Jan van Goethem M, Kiewiet H, Olivari F, Meyer C, Poppe B, Brandenburg S. Investigating the lateral dose response functions of point detectors in proton beams. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac783c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 06/13/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. Point detector measurements in proton fields are perturbed by the volume effect originating from geometrical volume-averaging within the extended detector’s sensitive volume and density perturbations by non-water equivalent detector components. Detector specific lateral dose response functions K(x) can be used to characterize the volume effect within the framework of a mathematical convolution model, where K(x) is the convolution kernel transforming the true dose profile D(x) into the measured signal profile of a detector M(x). The aim of this work is to investigate K(x) for detectors in proton beams. Approach. The K(x) for five detectors were determined by iterative deconvolution of measurements of D(x) and M(x) profiles at 2 cm water equivalent depth of a narrow 150 MeV proton beam. Monte Carlo simulations were carried out for two selected detectors to investigate a potential energy dependence, and to study the contribution of volume-averaging and density perturbation to the volume effect. Main results. The Monte Carlo simulated and experimentally determined K(x) agree within 2.1% of the maximum value. Further simulations demonstrate that the main contribution to the volume effect is volume-averaging. The results indicate that an energy or depth dependence of K(x) is almost negligible in proton beams. While the signal reduction from a Semiflex 3D ionization chamber in the center of a gaussian shaped field with 2 mm sigma is 32% for photons, it is 15% for protons. When measuring the field with a microDiamond the trend is less pronounced and reversed with a signal reduction for protons of 3.9% and photons of 1.9%. Significance. The determined K(x) can be applied to characterize the influence of the volume effect on detectors measured signal profiles at all clinical proton energies and measurement depths. The functions can be used to derive the actual dose distribution from point detector measurements.
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Olivari F, van der Graaf E, van Goethem M, Brandenburg S. PO-1591 A simple proton-radiography system for accurate RSP measurements in proton therapy. Radiother Oncol 2022. [DOI: 10.1016/s0167-8140(22)03555-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Würl M, Englbrecht FS, Lehrack S, Gianoli C, Lindner FH, Rösch TF, Haffa D, Olivari F, Petasecca M, Lerch MLF, Pogossov A, Tran LT, Assmann W, Schreiber J, Rosenfeld AB, Parodi K. Time-of-flight spectrometry of ultra-short, polyenergetic proton bunches. Rev Sci Instrum 2018; 89:123302. [PMID: 30599609 DOI: 10.1063/1.5052059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
A common approach for spectrum determination of polyenergetic proton bunches from laser-ion acceleration experiments is based on the time-of-flight (TOF) method. However, spectra obtained using this method are typically given in relative units or are estimated based on some prior assumptions on the energy distribution of the accelerated ions. In this work, we present a new approach using the TOF method that allows for an absolute energy spectrum reconstruction from a current signal acquired with a sub-nanosecond fast and 10 µm thin silicon detector. The reconstruction is based on solving a linear least-squares problem, taking into account the response function of the detection system. The general principle of signal generation and spectrum reconstruction by setting up an appropriate system response matrix is presented. Proof-of-principle experiments at a 12 MV Tandem accelerator using different nanosecond-short (quasi-)monoenergetic and polyenergetic proton bunches at energies up to 20 MeV were successfully performed. Within the experimental uncertainties of 2.4% and 12.1% for energy and particle number, respectively, reconstructed energy distributions were found in excellent agreement with the spectra calculated using Monte Carlo simulations and measured by a magnetic spectrometer. This TOF method can hence be used for absolute online spectrometry of laser-accelerated particle bunches.
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Affiliation(s)
- Matthias Würl
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Franz S Englbrecht
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Sebastian Lehrack
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Chiara Gianoli
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Florian H Lindner
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Thomas F Rösch
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Daniel Haffa
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Francesco Olivari
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Marco Petasecca
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Michael L F Lerch
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Alexandre Pogossov
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Linh T Tran
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Walter Assmann
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Jörg Schreiber
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
| | - Anatoly B Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Katia Parodi
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
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Englbrecht FS, Würl M, Olivari F, Ficorella A, Kreuzer C, Lindner FH, Palma MD, Pancheri L, Betta GFD, Schreiber J, Quaranta A, Parodi K. AN ONLINE, RADIATION HARD PROTON ENERGY-RESOLVING SCINTILLATOR STACK FOR LASER-DRIVEN PROTON BUNCHES. Radiat Prot Dosimetry 2018; 180:291-295. [PMID: 29415243 DOI: 10.1093/rpd/ncy008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Indexed: 06/08/2023]
Abstract
We report on a scintillator-based online detection system for the spectral characterization of polychromatic proton bunches. Using up to nine stacked layers of radiation hard polysiloxane scintillators, coupled to and readout edge-on by a large area pixelated CMOS detector, impinging polychromatic proton bunches were characterized. The energy spectra were reconstructed using calibration data and simulated using Monte-Carlo simulations. Despite the scintillator stack showed some problems like thickness inhomogeneities and unequal layer coupling, the prototype allows to obtain a first estimate of the energy spectrum of proton beams.
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Affiliation(s)
- Franz Siegfried Englbrecht
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching/München, Germany
| | - Matthias Würl
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching/München, Germany
| | - Francesco Olivari
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching/München, Germany
| | - Andrea Ficorella
- Department of Industrial Engineering, University of Trento, Trento, Italy
- INFN TIFPA, Trento, Italy
| | - Christian Kreuzer
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching/München, Germany
| | - Florian H Lindner
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching/München, Germany
| | - Matteo Dalla Palma
- Department of Industrial Engineering, University of Trento, Trento, Italy
- INFN TIFPA, Trento, Italy
| | - Lucio Pancheri
- Department of Industrial Engineering, University of Trento, Trento, Italy
- INFN TIFPA, Trento, Italy
| | - Gian-Franco Dalla Betta
- Department of Industrial Engineering, University of Trento, Trento, Italy
- INFN TIFPA, Trento, Italy
| | - Jörg Schreiber
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching/München, Germany
- Max Planck Institute of Quantum Optics, Garching/München, Germany
| | - Alberto Quaranta
- Department of Industrial Engineering, University of Trento, Trento, Italy
- INFN TIFPA, Trento, Italy
| | - Katia Parodi
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching/München, Germany
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Olivari F, de la Fuente M, López I. [Smoking among elementary school children. Study in a population of low socioeconomic level]. Rev Med Chil 1989; 117:861-6. [PMID: 2519443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We surveyed a probabilistic sample of 1383 school children attending elementary school (5th to 8th grade) in La Pincoya, a neighborhood of northern Santiago. 53.7% had smoked at least once, and 1 out of 5 were regular smokers of 1-4 cigarettes (72%) or more than 5 cigarettes a day (14%). The incidence of smoking was higher among boys and increased with age. Smoking occurs in different places including the street (19%). About 60% of children get their cigarettes from other children or adults. Those who buy, do so by units rather than packs. The incidence of smoking raised to 64% among children of parents who smoked. Pleasure or imitation were quoted as main reasons for smoking.
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Bondi P, Olivari F, López IM, Vignau JP, Sepúlveda H. [Physical growth and morbidity in the 1st year of life based on birth weight]. Rev Chil Pediatr 1985; 56:352-7. [PMID: 3835604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Olivari F, Duffau G, Hormazábal J. [Preparation of oral rehydration solution at home]. Rev Chil Pediatr 1985; 56:83-6. [PMID: 4089273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Beckmann E, Meyer R, Desamari K, Thiele J, Haring K, Hanslian R, Bosse J, Stock A, Kr�ss G, Thiele E, Liesche O, Junker F, Rimini E, Olivari F, R�gheimer L, Rudolfi E, Gonder L, Mc. Intosh D, Archibald EH, Weber W. Ebullioskopie. Anal Bioanal Chem 1912. [DOI: 10.1007/bf01470369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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