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Llopart-Babot I, Vasile M, Dobney A, Russell B, Kolmogorova S, Boden S, Bruggeman M, Leermakers M, Qiao J, De Souza V, Tarancón A, Bagán H, Warwick P. A comparison of different approaches for the analysis of 36Cl in graphite samples. Appl Radiat Isot 2023; 202:111046. [PMID: 37778141 DOI: 10.1016/j.apradiso.2023.111046] [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] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
This study compares different approaches for the quantification of the massic activity of 36Cl in graphite samples. All approaches consisted of a combustion step in combination with a trapping solution to collect the volatile elements. Two different resins were used to separate 36Cl from the matrix (CL resin and PS resin). Liquid scintillation counting (LSC), scintillation counting (SC) and tandem inductively coupled plasma mass spectrometry (ICP-MS/MS) were used to quantify 36Cl activity. The chemical yield in all approaches was determined by means of ion chromatography (IC). In addition, the methods were applied to a real activated graphite sample.
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Affiliation(s)
- I Llopart-Babot
- SCK CEN, Boeretang 200, 2400, Mol, Belgium; VUB, AMGC, Pleinlaan 2, 1050, Brussels, Belgium.
| | - M Vasile
- SCK CEN, Boeretang 200, 2400, Mol, Belgium
| | - A Dobney
- SCK CEN, Boeretang 200, 2400, Mol, Belgium
| | - B Russell
- Nuclear Metrology Group, National Physical Laboratory, Hampton Road, Teddington, TW11 OLW, UK
| | - S Kolmogorova
- Nuclear Metrology Group, National Physical Laboratory, Hampton Road, Teddington, TW11 OLW, UK
| | - S Boden
- SCK CEN, Boeretang 200, 2400, Mol, Belgium
| | | | | | - J Qiao
- Department of Environmental and Resource Engineering, Technical University of Denmark, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - V De Souza
- SCK CEN, Boeretang 200, 2400, Mol, Belgium
| | - A Tarancón
- Departament d'Enginyeria Química i Química Analítica, Universitat de Barcelona, Marti i Franqués, 1-1, 08028, Barcelona, Spain
| | - H Bagán
- Departament d'Enginyeria Química i Química Analítica, Universitat de Barcelona, Marti i Franqués, 1-1, 08028, Barcelona, Spain
| | - P Warwick
- University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UK
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Hamagami S, Fujino S, Yamada T. Performance evaluation of alpha-particle discrimination using ultra-thin plastic scintillation sheets and their application to alpha-emitters for targeted alpha therapy. Appl Radiat Isot 2023; 202:111036. [PMID: 37774579 DOI: 10.1016/j.apradiso.2023.111036] [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] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 09/06/2023] [Accepted: 09/21/2023] [Indexed: 10/01/2023]
Abstract
Alpha-particle discrimination using ultra-thin plastic scintillator sheets for measuring the activity of α-emitters under the existence of α- and β-emitters was investigated. 241Am, 32P and 223Ra were also used to evaluate the applicability of the present technique to α-emitters for medicine, and the self-absorption effect due to additives was investigated for validation. The results demonstrated that ≥95% of detection efficiency for α-particles emitted from 241Am with ≤1% β-contribution of 32P for the low carrier salt concentration solution. Regarding using 223Ra, ≥90% of α-efficiency was achievable with ≤1% β-contribution through sufficient dilution and selection of scintillator sheets of appropriate thicknesses.
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Affiliation(s)
- Sena Hamagami
- Oarai Research & Development Institute, Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki-ken, 311-1393, Japan
| | - Shunsuke Fujino
- Nuclear Science Research Institute, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki, 319-1195, Japan
| | - Takahiro Yamada
- Atomic Energy Research Institute, Kindai University, 3-4-1, Kowakae, Higashiosaka c., Osaka, 577-8502, Japan.
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Tanaka Y, Hashimoto M, Ishigami M, Nakano M, Hasegawa T. Development of a novel delivery quality assurance system based on simultaneous verification of dose distribution and binary multi-leaf collimator opening in helical tomotherapy. Radiat Oncol 2023; 18:180. [PMID: 37919745 PMCID: PMC10621123 DOI: 10.1186/s13014-023-02366-6] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 10/22/2023] [Indexed: 11/04/2023] Open
Abstract
BACKGROUND Intensity-modulated radiation therapy (IMRT) requires delivery quality assurance (DQA) to ensure treatment accuracy and safety. Irradiation techniques such as helical tomotherapy (HT) have become increasingly complex, rendering conventional verification methods insufficient. This study aims to develop a novel DQA system to simultaneously verify dose distribution and multi-leaf collimator (MLC) opening during HT. METHODS We developed a prototype detector consisting of a cylindrical plastic scintillator (PS) and a cooled charge-coupled device (CCD) camera. Scintillation light was recorded using a CCD camera. A TomoHDA (Accuray Inc.) was used as the irradiation device. The characteristics of the developed system were evaluated based on the light intensity. The IMRT plan was irradiated onto the PS to record a moving image of the scintillation light. MLC opening and light distribution were obtained from the recorded images. To detect MLC opening, we placed a region of interest (ROI) on the image, corresponding to the leaf position, and analyzed the temporal change in the light intensity within each ROI. Corrections were made for light changes due to differences in the PS shape and irradiation position. The corrected light intensity was converted into the leaf opening time (LOT), and an MLC sinogram was constructed. The reconstructed MLC sinogram was compared with that calculated using the treatment planning system (TPS). Light distribution was obtained by integrating all frames obtained during IMRT irradiation. The light distribution was compared with the dose distribution calculated using the TPS. RESULTS The LOT and the light intensity followed a linear relationship. Owing to MLC movements, the sensitivity and specificity of the reconstructed sinogram exceeded 97%, with an LOT error of - 3.9 ± 7.8%. The light distribution pattern closely resembled that of the dose distribution. The average dose difference and the pass rate of gamma analysis with 3%/3 mm were 1.4 ± 0.2% and 99%, respectively. CONCLUSION We developed a DQA system for simultaneous and accurate verification of both dose distribution and MLC opening during HT.
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Affiliation(s)
- Yuichi Tanaka
- Graduate School of Medical Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara-shi, Kanagawa, Japan.
| | - Masatoshi Hashimoto
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara-shi, Kanagawa, Japan
| | - Minoru Ishigami
- Department of Radiology, Kitasato University Hospital, 1-15-1 Kitazato, Minami-ku, Sagamihara-shi, Kanagawa, Japan
| | - Masahiro Nakano
- Department of Radiation Oncology, Kitasato University School of Medicine, 1-15-1 Kitazato, Minami-ku, Sagamihara-shi, Kanagawa, Japan
| | - Tomoyuki Hasegawa
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara-shi, Kanagawa, Japan
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Bagherzadeh-Atashchi S, Ghal-Eh N, Rahmani F, Izadi-Najafabadi R, Bedenko SV. Neutron spectroscopy with TENIS using an artificial neural network. Appl Radiat Isot 2023; 201:111035. [PMID: 37741070 DOI: 10.1016/j.apradiso.2023.111035] [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] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 08/20/2023] [Accepted: 09/13/2023] [Indexed: 09/25/2023]
Abstract
In this research, a ThErmal Neutron Imaging System (TENIS) consisting of two perpendicular sets of plastic scintillator arrays for boron neutron capture therapy (BNCT) application has been investigated in a completely different approach for neutron energy spectrum unfolding. TENIS provides a thermal neutron map based on the detection of 2.22 MeV gamma-rays resulting from 1H(nth, γ)2D reactions, but in the present study, the 70-pixel thermal neutron images have been used as input data for unfolding the energy spectrum of incident neutrons. Having generated the thermal neutron images for 109 incident mono-energetic neutrons, a 70 × 109 response matrix has been generated using the MCNPX2.6 code for feeding into the artificial neural network tools of MATLAB. The errors of the final results for mono-energetic neutron sources are less than 10% and the root mean square error (RMSE) for the unfolded neutron spectrum of 252Cf is about 0.01. The agreement of the unfolding results for mono-energetic and 252Cf neutron sources confirms the performance of the TENIS system as a neutron spectrometer.
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Affiliation(s)
- S Bagherzadeh-Atashchi
- Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, P.O. Box 91775-1436, Mashhad, Iran
| | - N Ghal-Eh
- Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, P.O. Box 91775-1436, Mashhad, Iran.
| | - F Rahmani
- Department of Physics, K. N. Toosi University of Technology, P.O. Box 16315-1618, Tehran, Iran
| | - R Izadi-Najafabadi
- Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, P.O. Box 91775-1436, Mashhad, Iran
| | - S V Bedenko
- School of Nuclear Science and Engineering, Tomsk Polytechnic University, P.O. Box 634050, Tomsk, Russian Federation
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Mianowski S, De Angelis N, Brylew K, Hulsman J, Kowalski T, Kusyk S, Mianowska Z, Mietelski J, Rybka D, Swakon J, Wrobel D. Proton irradiation of plastic scintillator bars for POLAR-2. Exp Astron (Dordr) 2023; 56:355-370. [PMID: 38145002 PMCID: PMC10746763 DOI: 10.1007/s10686-023-09906-8] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 06/21/2023] [Indexed: 12/26/2023]
Abstract
POLAR-2, a plastic scintillator based Compton polarimeter, is currently under development and planned for a launch to the China Space Station in 2025. It is intended to shed a new light on our understanding of Gamma-Ray Bursts by performing high precision polarization measurements of their prompt emission. The instrument will be orbiting at an average altitude of 383 km with an inclination of 42° and will be subject to background radiation from cosmic rays and solar events. In this work, we tested the performance of plastic scintillation bars, EJ-200 and EJ-248M from Eljen Technology, under space-like conditions, that were chosen as possible candidates for POLAR-2. Both scintillator types were irradiated with 58 MeV protons at several doses from 1.89 Gy(corresponding to about 13 years in space for POLAR-2) up to 18.7 Gy, that goes far beyond the expected POLAR-2 life time. Their respective properties, expressed in terms of light yield, emission and absorption spectra, and activation analysis due to proton irradiation are discussed. Scintillators activation analyses showed a dominant contribution of β + decay with a typical for this process gamma-ray energy line of 511 keV.
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Affiliation(s)
- Slawomir Mianowski
- National Centre for Nuclear Research, A. Soltana 7 Street, 05400 Otwock, Poland
| | - Nicolas De Angelis
- DPNC, University of Geneva, 24 Quai Ernest-Ansermet, CH-1205 Geneva, Switzerland
| | - Kamil Brylew
- National Centre for Nuclear Research, A. Soltana 7 Street, 05400 Otwock, Poland
| | - Johannes Hulsman
- DPNC, University of Geneva, 24 Quai Ernest-Ansermet, CH-1205 Geneva, Switzerland
| | - Tomasz Kowalski
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152 Street, 31342 Krakow, Poland
| | - Sebastian Kusyk
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152 Street, 31342 Krakow, Poland
| | - Zuzanna Mianowska
- National Centre for Nuclear Research, A. Soltana 7 Street, 05400 Otwock, Poland
| | - Jerzy Mietelski
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152 Street, 31342 Krakow, Poland
| | - Dominik Rybka
- National Centre for Nuclear Research, A. Soltana 7 Street, 05400 Otwock, Poland
| | - Jan Swakon
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152 Street, 31342 Krakow, Poland
| | - Damian Wrobel
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152 Street, 31342 Krakow, Poland
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Chandler C, Porcincula DH, Ford MJ, Kolibaba TJ, Fein-Ashley B, Brodsky J, Killgore JP, Sellinger A. Influence of fluorescent dopants on the vat photopolymerization of acrylate-based plastic scintillators for application in neutron/gamma pulse shape discrimination. Addit Manuf 2023; 73:10.1016/j.addma.2023.103688. [PMID: 37719134 PMCID: PMC10502904 DOI: 10.1016/j.addma.2023.103688] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Plastic scintillators, a class of solid-state materials used for radiation detection, were additively manufactured with vat photopolymerization. The photopolymer resins consisted of a primary dopant and a secondary dopant dissolved in a bisphenol A ethoxylate diacrylate-based matrix. The absorptive dopants significantly influence important print parameters, for example, secondary dopants decrease the light penetration depth by a factor > 12 ×. The primary dopant 2,5-diphenyloxazole had minimal impact on the printing process even when loaded at 25 % by mass of the resin. Working curve measurements, which relate energy dose to cure depth, were performed as a function of feature size to further assess the influence of dopants. Photopatterns smaller than 150 μm width had apparent increases in critical energy dose compared to larger photopatterns, while all resins maintained printed features in line gratings with 50 μm of separation. Printed scintillator monoliths were compared to scintillators cast by traditional molding, demonstrating that the layer-by-layer printing process does not decrease scintillation response. A maximum light output of 31 % of a benchmark plastic scintillator (EJ-200) and successful pulse shape discrimination were achieved with 20 % by mass 2,5-diphenyloxazole as the primary dopant and 0.1 % by mass 9,9-dimethyl-2,7-distyrylfluorene as the secondary dopant in printed scintillator samples.
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Affiliation(s)
- Caleb Chandler
- Colorado School of Mines, Department of Chemistry, 1500 Illinois St., Golden, CO 80401, United States of America
| | - Dominique H. Porcincula
- Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550, United States of America
| | - Michael J. Ford
- Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550, United States of America
| | - Thomas J. Kolibaba
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
| | - Benjamin Fein-Ashley
- Colorado School of Mines, Department of Chemistry, 1500 Illinois St., Golden, CO 80401, United States of America
| | - Jason Brodsky
- Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550, United States of America
| | - Jason P. Killgore
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
| | - Alan Sellinger
- Colorado School of Mines, Department of Chemistry, 1500 Illinois St., Golden, CO 80401, United States of America
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Mubashir H, Mounja MM, Salvi S, Telloli C, Cicconi F, Rizzo A. Set up and test of an anticoincidence system for the detection of radioactive xenon by gamma spectrometry system. J Environ Radioact 2023; 259-260:107107. [PMID: 36646011 DOI: 10.1016/j.jenvrad.2022.107107] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 10/21/2022] [Accepted: 12/30/2022] [Indexed: 06/17/2023]
Abstract
The aim of this work is based on the optimisation of a gamma spectrometry system in anticoincidence for the detection of noble gases, in particular the radioactive isotopes of xenon. These four radionuclides are of particular interest for the Comprehensive Nuclear Test-Ban Treaty (CTBT). The Laboratory of the ENEA Research Centre of Brasimone, where the experimental apparatus has been set up to carry out the measurements of 131mXe, 133Xe, 133mXe and 135Xe, is able to provide, if necessary, data and analysis on noble gases. The apparatus provides for the sampling of outdoor air, the passage through filters and in activated carbons maintained at cryogenic temperatures to allow xenon absorption. Finally, gas extraction and xenon volumes are analyzed by means of gas chromatography and a thermal conductivity detector. At the end of the extraction an aluminium cylinder containing radioxenon is analyzed by high resolution gamma spectroscopy using a High Purity Germanium Detector P-type. The signals produced by the interaction of cosmic rays with the crystal have been recognized as the main cause of the increase of the detector background because they give rise to the Compton continuum and, as a result, they affect the value of the minimum detectable activity (MDA). In order to overcome this effect, a system in anticoincidence has been developed using two plastic scintillators, placed over the shielding of the HPGe detector, which send pulses recording within a time delay window located in the germanium multichannel analyzer: at the time the signal arrives from the scintillator, the gate blocks data acquisition to avoid recording pulses generated by cosmic radiation. For both configurations of the system (with and without the anticoincidence apparatus operating) the energy, and efficiency calibrations have been carried out using a certified multigamma-ray calibration source to assess the performance.
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Affiliation(s)
- Hassan Mubashir
- Electrical Engineering Department, Bologna University, Viale del Risorgimento 2, Bologna, Italy
| | - Mohamed Mahmoud Mounja
- ARSN, Mauritanian National Authority of Radiation Protection, Nuclear Security, and Safety, Nouakchott, Mauritania
| | - Stefano Salvi
- ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development Fusion and Technology for Nuclear Safety and Security Department Nuclear Safety, Security and Sustainability Division, via Martiri di Monte Sole 4, Bologna, Italy
| | - Chiara Telloli
- ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development Fusion and Technology for Nuclear Safety and Security Department Nuclear Safety, Security and Sustainability Division, via Martiri di Monte Sole 4, Bologna, Italy.
| | - Flavio Cicconi
- ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development Fusion and Technology for Nuclear Safety and Security Department Nuclear Safety, Security and Sustainability Division, via Martiri di Monte Sole 4, Bologna, Italy
| | - Antonietta Rizzo
- ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development Fusion and Technology for Nuclear Safety and Security Department Nuclear Safety, Security and Sustainability Division, via Martiri di Monte Sole 4, Bologna, Italy
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8
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Llopart-Babot I, Vasile M, Tarancón A, Bagán H, Dobney A, Boden S, Bruggeman M, Leermakers M, Qiao J, Warwick P. Investigation of a new approach for 36Cl determination in solid samples using plastic scintillators. Appl Radiat Isot 2023; 193:110646. [PMID: 36603458 DOI: 10.1016/j.apradiso.2022.110646] [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] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/23/2022] [Accepted: 12/30/2022] [Indexed: 01/01/2023]
Abstract
This work reports a new approach for the determination of 36Cl in radioactive waste samples from nuclear decommissioning, wherein novel plastic scintillator (PS) materials were used for the concentration of 36Cl prior to the detection with scintillation counting. Different plastic scintillator (PS) materials were tested for their selective absorption and detection of 36Cl activity in solid samples. PS microspheres (PSm), cross-linked PSm (CPSm) and PS resin have been investigated. PS resin was identified as the most suitable material for 36Cl analysis. Pyrolysis and subsequent trapping of the volatile elements in a bubbler was used. The trapping solution was finally loaded onto a cartridge of the PS resin. Scintillation counting and ion chromatography were used to determine the activity concentration and the chemical recovery, respectively.
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Affiliation(s)
- I Llopart-Babot
- SCK CEN, Boeretang 200, 2400, Mol, Belgium; VUB, AMGC, Pleinlaan 2, 1050, Brussels, Belgium.
| | - M Vasile
- SCK CEN, Boeretang 200, 2400, Mol, Belgium
| | - A Tarancón
- Departament d'Enginyeria Química i Química Analítica, Universitat de Barcelona, Marti i Franqués, 1-11, 08028, Barcelona, Spain
| | - H Bagán
- Departament d'Enginyeria Química i Química Analítica, Universitat de Barcelona, Marti i Franqués, 1-11, 08028, Barcelona, Spain
| | - A Dobney
- SCK CEN, Boeretang 200, 2400, Mol, Belgium
| | - S Boden
- SCK CEN, Boeretang 200, 2400, Mol, Belgium
| | | | | | - J Qiao
- Department of Environmental and Resource Engineering, Technical University of Denmark, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - P Warwick
- University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UK
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Ravindra A, Kulkarni DB, Sharma R, Dahiwale SS, Dhole SD, Prasad S S, Sathian V. Activity measurement of mixed complex radionuclide like 152Eu with different methods. Appl Radiat Isot 2022; 185:110228. [PMID: 35421808 DOI: 10.1016/j.apradiso.2022.110228] [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] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/15/2022] [Accepted: 04/04/2022] [Indexed: 12/01/2022]
Abstract
152Eu has been standardized by three independent 4π β-γ coincidence counting systems with beta detectors as proportional counter, plastic scintillator and liquid scintillator along with the CIEMAT/NIST method. The average activity concentration by primary methods was linked to key comparison reference value (KCRV) by comparing it with that of 4π γ ionization chamber (GIC) whose calibration factor was determined from the KCRV (BIPM.RI(II)-K1.Eu-152 and CCRI(II)-K2.Eu-152) and deviates from GIC by ± 0.16% indicating good agreement within standard uncertainties.
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Affiliation(s)
| | - D B Kulkarni
- Radiation Safety Systems Division, BARC, Mumbai, India
| | - Ritu Sharma
- Radiation Safety Systems Division, BARC, Mumbai, India
| | - S S Dahiwale
- Department of Physics, Savitiribai Phule Pune University, Pune, India
| | - Sanjay D Dhole
- Department of Physics, Savitiribai Phule Pune University, Pune, India
| | | | - V Sathian
- Radiation Safety Systems Division, BARC, Mumbai, India
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Kikuta S, Sakata D, Fukuda S. Computational modeling for the evaluation of suppressed scintillation yields in plastic scintillators using Geant4. Phys Med 2021; 89:258-64. [PMID: 34464937 DOI: 10.1016/j.ejmp.2021.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 08/03/2021] [Accepted: 08/03/2021] [Indexed: 11/23/2022] Open
Abstract
The yield of scintillation photons emitted from scintillators is considered to be proportional to the LET (linear energy transfer) which is energy distribution per unit length, in the low-LET domain, but not proportional in the high LET domain due to the suppression yield from the so-called quenching effect. Ogawa et al. proposed a computational method to estimate scintillation yield using Monte Carlo simulations considering the principle of the FRET (fluorescence resonance energy transfer) process, which is a phenomenon of energy transfer between fluorescent molecules. In their study, the track structure simulations could reproduce measured yields of scintillation. However, Ogawa et al.'s model was not suitable for estimating the scintillation yields when the particle energy was low when using condensed history simulations. Therefore, we propose a new method for estimating scintillation yields more accurately using Geant4 to improve the model calculations based on condensed history simulations. We simulated the local energy deposition pattern in a NE102A plastic scintillator to calculate the number of excitors in the microscopic volume for various nuclides (helium to argon ions). The suppressed scintillation yields were estimated using the model calculations of sequential FRET processes while considering the inactivation of the excitors selected as donors of the FRET process. The model calculations successfully reproduced the experimental scintillation yields within 10% error for the lighter ions up to neon. However, when the analysis was repeated for silicon and argon, the maximum error in the scintillation yields increased up to 27%. The proposed computational model for the evaluation of the suppressed scintillation yields emitted from NE102A scintillator irradiated with heavy ions using sequential FRET calculations with condensed history method returned simulated scintillation yields.
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11
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Yazdandoust H, Ghal-Eh N, Firoozabadi MM. TENIS - ThErmal Neutron Imaging System for use in BNCT. Appl Radiat Isot 2021; 176:109755. [PMID: 34243019 DOI: 10.1016/j.apradiso.2021.109755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/09/2021] [Accepted: 04/23/2021] [Indexed: 10/21/2022]
Abstract
A thermal neutron flux measurement tool with two perpendicular sets of plastic scintillator arrays was designed and simulated (Ghal-Eh and Green, 2016) with the MCNPX code (Version 2.6.0, with ENDF/B-VII cross section library (ENDF, 2011)). The proposed system aimed to provide a thermal neutron map based on the detection of 2.22 MeV gamma-rays resulting from 1H(nth, γ)2D reactions. In the present work, using Monte Carlo code FLUKA and its scintillation light transport capability, several important upgrades were carried out to include the light transport modeling in the response of plastic scintillators, analyze the cross-talk phenomenon, optimize the system geometry, and also provide a new approach in thermal neutron image reconstruction. The results showed that the last two cases played a significant role in improving the longitudinal profile of thermal neutron flux.
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Affiliation(s)
- H Yazdandoust
- Department of Physics, Faculty of Sciences, University of Birjand, P.O. Box 97175-615, Birjand, Iran
| | - N Ghal-Eh
- Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, P.O. Box 91775-1436, Mashhad, Iran.
| | - M M Firoozabadi
- Department of Physics, Faculty of Sciences, University of Birjand, P.O. Box 97175-615, Birjand, Iran
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Bohra F, Atanackovic J, Byun SH, Hanu AR, Laranjeiro A. Quantification of pure beta spectra in mixed beta gamma fields as part of eye lens dosimetry at CANDU power plants. Appl Radiat Isot 2021; 174:109746. [PMID: 33930726 DOI: 10.1016/j.apradiso.2021.109746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 11/26/2022]
Abstract
To address the issue of eye lens dosimetry in nuclear industry, we initiated the project to quantify the beta and gamma-ray source term in CANDU power plants and to convert this source term into dosimetric quantities of interest, such as eye lens dose and personal dose equivalents Hp(10), Hp(0.07). This way, the eye lens dose can be compared with dosimetric operational quantities to evaluate whether independent dosimetry is required for eye lens protection, or present dosimetry is adequate.
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Affiliation(s)
- F Bohra
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada
| | - J Atanackovic
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada; Ontario Power Generation, Whitby, ON, L1N 9E3, Canada.
| | - S H Byun
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada
| | - A R Hanu
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada; Bruce Power, Tiverton, ON, N0G 2T0, Canada
| | - A Laranjeiro
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada
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Madden L, Roberts N, Jelen U, Dong B, Holloway L, Metcalfe P, Rosenfeld A, Li E. In-line MRI-LINAC depth dose measurements using an in-house plastic scintillation dosimeter. Biomed Phys Eng Express 2021; 7. [PMID: 33530066 DOI: 10.1088/2057-1976/abe295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 02/02/2021] [Indexed: 11/12/2022]
Abstract
Plastic scintillation dosimeters (PSDs) have many properties that make them desirable for relative dosimetry with MRI-LINACs. An in-house PSD, Farmer ionisation chamber and Gafchromic EBT3 film were used to measure central axis percentage depth dose distributions (PDDs) at the Australian MRI-LINAC Mean errors were calculated between each detector's responses, where the in-house PSD was on average within 0.7% of the Farmer chamber and 1.4% of film, while the Farmer chamber and film were on average within 1.1% of each other. However, the PSD systematically over-estimated the dose as depth increased, approaching a maximum overestimation of the order of 3.5% for the smallest field size measured. This trend was statistically insignificant for all other field sizes measured; further investigation is required to determine the source of this effect. The calculated values of mean absolute error are comparable to the those of trusted dosimeters reported in the literature. These mean absolute errors, and the ubiquity of desirable dosimetric qualities inherent to PSDs suggest that PSDs in general are accurate for relative dosimetry with the MRI-LINAC. Further investigation is required into the source of the reported systematic trends dependent on field-size and depth of measurement.
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Affiliation(s)
- Levi Madden
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Natalia Roberts
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Urszula Jelen
- GenesisCare St Vincent's Clinic, Darlinghurst, NSW 2010, Australia
| | - Bin Dong
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Lois Holloway
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia.,Liverpool Cancer Therapy Centre, Liverpool, NSW 2170, Australia.,Macauthur Cancer Therapy Clinic, Campbelltown, NSW 2560, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.,Illawarra Medical and Health Research Institute, University of Wollongong, NSW 2522, Australia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.,Illawarra Medical and Health Research Institute, University of Wollongong, NSW 2522, Australia
| | - Enbang Li
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia
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Posar JA, Davis J, Brace O, Sellin P, Griffith MJ, Dhez O, Wilkinson D, Lerch MLF, Rosenfeld A, Petasecca M. Characterization of a plastic dosimeter based on organic semiconductor photodiodes and scintillator. Phys Imaging Radiat Oncol 2020; 14:48-52. [PMID: 33458314 DOI: 10.1016/j.phro.2020.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 11/23/2022]
Abstract
Background and purpose Measurement of dose delivery is essential to guarantee the safety of patients undergoing medical radiation imaging or treatment procedures. This study aimed to evaluate the ability of organic semiconductors, coupled with a plastic scintillator, to measure photon dose in clinically relevant conditions, and establish its radiation hardness. Thereby, proving organic devices are capable of being a water-equivalent, mechanically flexible, real-time dosimeter. Materials and methods The shelf-life of an organic photodiode was analyzed to 40 kGy by comparison of the charge-collection-efficiency of a 520 nm light emitting diode. A non-irradiated and pre-irradiated photodiode was coupled to a plastic scintillator and their response to 6 MV photons was investigated. The dose linearity, dose-per-pulse dependence and energy dependence was characterized. Finally, the percentage depth dose (PDD) between 0.5 and 20 cm was compared with ionization chamber measurements. Results Sensitivity to 6 MV photons was (190 ± 0.28) pC/cGy and (170 ± 0.11) pC/cGy for the non-irradiated and pre-irradiated photodiode biased at -2 V. The response was independent of the dose-per-pulse between 0.031 and 0.34 mGy/pulse. An energy dependence was found for low keV energies, explained by the energy dependence of the scintillator which plateaued between 70 keV and 1.2 MeV. The PDD was within ±3% of the ionization chamber. Conclusion Coupling an organic photodiode with a plastic scintillator provided reliable measurement of a range of photon energies. Dose-per-pulse and energy independence advocate their use as a dosimeter, specifically image-guided treatment without beam-quality correction factors. Degradation effects of organic semiconducting materials deteriorate sensor response but can be stabilized.
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15
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Muenkel J, Xu Z, Traughber BJ, Baig T, Xu K, Langmack C, Harris E, Podder TK. Feasibility of improving patient's safety with in vivo dose tracking in intracavitary and interstitial HDR brachytherapy. Brachytherapy 2020; 20:353-360. [PMID: 33187822 DOI: 10.1016/j.brachy.2020.09.010] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/29/2020] [Accepted: 09/14/2020] [Indexed: 11/19/2022]
Abstract
PURPOSE The in vivo dosimetric monitoring in HDR brachytherapy is important for improving patient safety. However, there are very limited options available for clinical application. In this study, we present a new in vivo dose measurement system with a plastic scintillating detector (PSD) for GYN HDR brachytherapy. METHODS An FDA approved PSD system, called OARtrac (AngioDynamics, Latham, NY), was used with various applicators for in vivo dose measurements for GYN patients. An institutional workflow was established for the clinical implementation of the dosimetric system. Action levels were proposed based on the measurement and system uncertainty for measurement deviations. From October 2018 to September 2019, a total of 75 measurements (48 fractions) were acquired from 14 patients who underwent HDR brachytherapy using either a multichannel cylinder, Venezia applicator, or Syed-Neblett template. The PSDs were placed in predetermined catheters/channels. A planning CT was acquired for treatment planning in Oncentra (Elekta, Version-4.5.2) TPS. The PSDs were contoured on the CT images, and the PSD D90% values were used as the expected doses for comparison with the measured doses. RESULTS The mean difference from patient measurements was -0.22% ± 5.98%, with 26% being the largest deviation from the expected value (Syed case). Large deviations were observed when detectors were placed in the area where dose rates were less than 1 cGy/s. CONCLUSIONS The establishment of clinical workflow for the in vivo dosimetry for both the intracavitary and interstitial GYN HDR brachytherapy will potentially improve the safety of the patient treatment.
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Affiliation(s)
- Jessica Muenkel
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH
| | - Zhengzheng Xu
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH.
| | - Bryan J Traughber
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH; School of Medicine, Case Western Reserve University, Cleveland, OH
| | - Tanvir Baig
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH
| | - Keying Xu
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH
| | - Christian Langmack
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH
| | - Eleanor Harris
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH; School of Medicine, Case Western Reserve University, Cleveland, OH
| | - Tarun K Podder
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH; School of Medicine, Case Western Reserve University, Cleveland, OH
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Madden L, Archer J, Li E, Jelen U, Dong B, Holloway L, Rosenfeld A. MRI-LINAC beam profile measurements using a plastic scintillation dosimeter. Phys Med 2020; 73:111-116. [PMID: 32361155 DOI: 10.1016/j.ejmp.2020.04.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 01/21/2020] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 10/24/2022] Open
Abstract
Plastic scintillation dosimeters (PSDs) possess many desirable qualities for dosimetry with LINACs. These qualities are expected to make PSDs effective for MRI-LINAC dosimetry, however little research has been conducted investigating their dosimetric performance with MRI-LINACs. In this work, an in-house PSD was used to measure 8 beam profiles with an in-line MRI-LINAC, compared with film measurements. One dimensional global gamma indices (γ) and corresponding γ pass rates were calculated to compare PSD and film profiles for the 1%/1 mm, 2%/2 mm and 3%/3 mm criterion. The mean global pass rates were 85.8%, 97.5% and 99.4% for the 1%/1 mm, 2%/2 mm and 3%/3 mm criteria, respectively. The majority of the γ failures occurred in the penumbral regions. Penumbra widths were measured to be slightly narrower with the PSD compared to film, however, the uncertainties in the measured penumbra widths brought the PSD and film penumbra widths into agreement. Differences in dose were calculated between the PSD and film, and remained within 2.2% global agreement for the central regions and 1.5% global agreement for out of field regions. These values for range of agreement were similar to the those reported in the literature for other dosimeters which are trusted for relative MRI-LINAC dosimetry.
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Affiliation(s)
- Levi Madden
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia; Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - James Archer
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia
| | - Enbang Li
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.
| | - Urszula Jelen
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Bin Dong
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Lois Holloway
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia; Illawarra Medical and Health Research Institute, University of Wollongong, NSW 2522, Australia
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Tajudin SM, Namito Y, Sanami T, Hirayama H. Response of plastic scintillator to gamma sources. Appl Radiat Isot 2020; 159:109086. [PMID: 32250760 DOI: 10.1016/j.apradiso.2020.109086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 09/17/2019] [Accepted: 02/14/2020] [Indexed: 11/23/2022]
Abstract
In this study, we developed a method for directly determining the energy deposited over the entire energy range by monitoring the light output from a plastic scintillator under gamma irradiation. The relative light output was analyzed based on Birks' semi-empirical formula for ionization to obtain the quenching parameter as kB = 0.016 ± 0.0004 g cm-2 MeV-1. Comparisons of experimental and calculated results for the light output spectra showed that considering the quenching effect, background subtraction, source casing, and energy sampling were essential for achieving good agreement.
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18
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Lee HC, Shin WG, Choi HJ, Choi CI, Park CS, Kim HS, Min CH. Radioisotope identification using an energy-weighted algorithm with a proof-of-principle radiation portal monitor based on plastic scintillators. Appl Radiat Isot 2020; 156:109010. [PMID: 32056690 DOI: 10.1016/j.apradiso.2019.109010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 11/05/2019] [Accepted: 11/26/2019] [Indexed: 11/18/2022]
Abstract
In this study, we validated the feasibility of an energy weighted algorithm that highlights a characteristic area including the Compton edge as a single peak in a proof-of-principle radiation portal monitor system with a plastic scintillator measuring 50 × 100 × 5 cm3. We measured the energy weighted spectra with steel shielding and the dynamic movements of the 137Cs and 60Co sources. The results showed that the peak locations of each source could be identified under shielded or dynamic motion conditions, each within a maximum difference of 0.08 MeV.
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Affiliation(s)
- Hyun Cheol Lee
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
| | - Wook-Geun Shin
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
| | - Hyun Joon Choi
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
| | - Chang-Il Choi
- Radiological Emergency & Security Preparedness Department, Korea Institute of Nuclear Safety, Daejeon, Republic of Korea
| | - Chang Su Park
- Radiological Emergency & Security Preparedness Department, Korea Institute of Nuclear Safety, Daejeon, Republic of Korea
| | - Hong-Suk Kim
- Radiological Emergency & Security Preparedness Department, Korea Institute of Nuclear Safety, Daejeon, Republic of Korea
| | - Chul Hee Min
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea.
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Chaudhari SH, Dobhal R, Kinhikar RA, Kadam SS, Deshpande DD. Measurement of Total Scatter Factor for Stereotactic Cones with Plastic Scintillation Detector. J Med Phys 2017; 42:9-13. [PMID: 28405102 PMCID: PMC5370342 DOI: 10.4103/jmp.jmp_114_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Advanced radiotherapy modalities such as stereotactic radiosurgery (SRS) and image-guided radiotherapy may employ very small beam apertures for accurate localized high dose to target. Accurate measurement of small radiation fields is a well-known challenge for many dosimeters. The purpose of this study was to measure total scatter factors for stereotactic cones with plastic scintillation detector and its comparison against diode detector and theoretical estimates. Measurements were performed on Novalis Tx™ linear accelerator for 6MV SRS beam with stereotactic cones of diameter 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm. The advantage of plastic scintillator detector is in its energy dependence. The total scatter factor was measured in water at the depth of dose maximum. Total scatter factor with plastic scintillation detector was determined by normalizing the readings to field size of 10 cm × 10 cm. To overcome energy dependence of diode detector for the determination of scatter factor with diode detector, daisy chaining method was used. The plastic scintillator detector was calibrated against the ionization chamber, and the reproducibility in the measured doses was found to be within ± 1%. Total scatter factor measured with plastic scintillation detector was 0.728 ± 0.3, 0.783 ± 0.05, 0.866 ± 0.55, 0.885 ± 0.5, and 0.910 ± 0.06 for cone sizes of 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. Total scatter factor measured with diode detector was 0.733 ± 0.03, 0.782 ± 0.02, 0.834 ± 0.07, 0.854 ± 0.02, and 0.872 ± 0.02 for cone sizes of 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. The variation in the measurement of total scatter factor with published Monte Carlo data was found to be −1.3%, 1.9%, −0.4%, and 0.4% for cone sizes of 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. We conclude that total scatter factor measurements for stereotactic cones can be adequately carried out with a plastic scintillation detector. Our results show a high level of consistency within our data and compared well with published data.
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Affiliation(s)
- Suresh H Chaudhari
- Department of Radiation Oncology, Apollo Hospitals, Navi Mumbai, Maharashtra, India
| | - Rishabh Dobhal
- Department of Radiation Oncology, Batra Hospital and Medical Research Centre, New Delhi, India
| | - Rajesh A Kinhikar
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, Maharashtra, India
| | - Sudarshan S Kadam
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, Maharashtra, India
| | - Deepak D Deshpande
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, Maharashtra, India
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20
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Zboray R, Adams R, Kis Z. Fast neutron radiography and tomography at a 10MW research reactor beamline. Appl Radiat Isot 2016; 119:43-50. [PMID: 27842231 DOI: 10.1016/j.apradiso.2016.10.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 10/21/2016] [Accepted: 10/22/2016] [Indexed: 11/19/2022]
Abstract
Fast neutron imaging was performed using a beamline of the 10MW research reactor of the Budapest Neutron Centre, Hungary. A simple, low-cost 2D area detector has been used featuring a 8mm thick BC400 plastic scintillator converter screen and a CCD camera. A spatial resolution of around 1.3mm has been achieved. Typically 10min long exposures were needed to obtain reasonable quality radiographic images. For tomographic imaging typically several hours of acquisition were needed to obtain reasonable quality on non-symmetric and larger (e.g. 10×10×10cm3) objects. Due to the presence of a significant gamma background at the experimental position, massive (30cm thick) lead shielding and filtering was applied to the beam. The gamma contribution was mostly baseline independent of the object imaged and therefore could be subtracted, whereas the direct gamma contribution from the beam to the imaging detector signal is estimated to be less than 1%.
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Affiliation(s)
- R Zboray
- Paul Scherrer Institute, PSI Villigen CH-5232, Switzerland.
| | - R Adams
- Swiss Federal Institute of Technology Zurich, Sonnegstrasse 3, CH-8092 Zurich, Switzerland
| | - Z Kis
- Hungarian Academy of Science, Centre for Energy Research, 29-33 Konkoly Thege Miklos street, 1121 Budapest, Hungary
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Shan Q, Chu S, Ling Y, Cai P, Jia W. Designing a new type of neutron detector for neutron and gamma-ray discrimination via GEANT4. Appl Radiat Isot 2016; 110:200-4. [PMID: 26844541 DOI: 10.1016/j.apradiso.2016.01.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/16/2016] [Accepted: 01/24/2016] [Indexed: 11/21/2022]
Abstract
Design of a new type of neutron detector, consisting of a fast neutron converter, plastic scintillator, and Cherenkov detector, to discriminate 14-MeV fast neutrons and gamma rays in a pulsed n-γ mixed field and monitor their neutron fluxes is reported in this study. Both neutrons and gamma rays can produce fluorescence in the scintillator when they are incident on the detector. However, only the secondary charged particles of the gamma rays can produce Cherenkov light in the Cherenkov detector. The neutron and gamma-ray fluxes can be calculated by measuring the fluorescence and Cherenkov light. The GEANT4 Monte Carlo simulation toolkit is used to simulate the whole process occurring in the detector, whose optimum parameters are known. Analysis of the simulation results leads to a calculation method of neutron flux. This method is verified by calculating the neutron fluxes using pulsed n-γ mixed fields with different n/γ ratios, and the results show that the relative errors of all calculations are <5%.
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Unno Y, Sanami T, Sasaki S, Hagiwara M, Yunoki A. Simulation technique for extrapolation curves in 4πβ-γ coincidence counting method using EGS5 code. Appl Radiat Isot 2016; 109:363-8. [PMID: 26688354 DOI: 10.1016/j.apradiso.2015.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 12/04/2015] [Indexed: 11/22/2022]
Abstract
A simulation technique was developed for the extrapolation technique in 4πβ-γ coincidence counting method. Simultaneous emissions of β and γ rays were calculated using EGS5 code to obtain coincidence counting between both β and γ channels. The simulated extrapolation curves were compared with experimental data obtained with (134)Cs measurements using a plastic scintillator in the β channel. The variation of the extrapolation curves with γ-gate configuration was investigated by the simulation technique.
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Abstract
A new prototype device for beta-ray measurement, a plastic scintillation counter, was assembled as an alternative device to liquid scintillation counters. This device uses plastic scintillation sheets (PS sheets) as a sample applicator without the use of a liquid scintillator. The performance was evaluated using tritium labeled compounds, and good linearity was observed between the activity and net count rate. The calculated detection limit of the device was 0.01 Bq mL(-1) after 10 h measurement for 2 mL sample.
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Affiliation(s)
- Etsuko Furuta
- Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo 112-8610, Japan.
| | - Takao Kawano
- The National Institute for Fusion Science, 322-6 Shimo-ishichou, Toki-city, Gifu 509-5202, Japan
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Sanada Y, Torii T. Aerial radiation monitoring around the Fukushima Dai-ichi Nuclear Power Plant using an unmanned helicopter. J Environ Radioact 2015; 139:294-299. [PMID: 25053518 DOI: 10.1016/j.jenvrad.2014.06.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 06/26/2014] [Accepted: 06/26/2014] [Indexed: 06/03/2023]
Abstract
The Great East Japan Earthquake on March 11, 2011 generated a series of large tsunami that seriously damaged the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), which resulted in the release of radioactive materials into the environment. To provide further details regarding the distribution of air dose rate and the distribution of radioactive cesium ((134)Cs and (137)Cs) deposition on the ground within a radius of approximately 5 km from the nuclear power plant, we carried out measurements using an unmanned helicopter equipped with a radiation detection system. The distribution of the air dose rate at a height of 1 m above the ground and the radioactive cesium deposition on the ground was calculated. Accordingly, the footprint of radioactive plumes that extended from the FDNPP was illustrated.
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Affiliation(s)
- Yukihisa Sanada
- Headquarters of Fukushima Partnership Operations, Japan Atomic Energy Agency, 2-2-2, Uchisaiwai-cho, Chiyoda-ku, Tokyo 100-8577, Japan.
| | - Tatsuo Torii
- Headquarters of Fukushima Partnership Operations, Japan Atomic Energy Agency, 2-2-2, Uchisaiwai-cho, Chiyoda-ku, Tokyo 100-8577, Japan
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Adams R, Zboray R, Cortesi M, Prasser HM. Conceptual design and optimization of a plastic scintillator array for 2D tomography using a compact D-D fast neutron generator. Appl Radiat Isot 2014; 86:63-70. [PMID: 24495568 DOI: 10.1016/j.apradiso.2014.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 12/20/2013] [Accepted: 01/08/2014] [Indexed: 10/25/2022]
Abstract
A conceptual design optimization of a fast neutron tomography system was performed. The system is based on a compact deuterium-deuterium fast neutron generator and an arc-shaped array of individual neutron detectors. The array functions as a position sensitive one-dimensional detector allowing tomographic reconstruction of a two-dimensional cross section of an object up to 10 cm across. Each individual detector is to be optically isolated and consists of a plastic scintillator and a Silicon Photomultiplier for measuring light produced by recoil protons. A deterministic geometry-based model and a series of Monte Carlo simulations were used to optimize the design geometry parameters affecting the reconstructed image resolution. From this, it is expected that with an array of 100 detectors a reconstructed image resolution of ~1.5mm can be obtained. Other simulations were performed in order to optimize the scintillator depth (length along the neutron path) such that the best ratio of direct to scattered neutron counts is achieved. This resulted in a depth of 6-8 cm and an expected detection efficiency of 33-37%. Based on current operational capabilities of a prototype neutron generator being developed at the Paul Scherrer Institute, planned implementation of this detector array design should allow reconstructed tomograms to be obtained with exposure times on the order of a few hours.
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Affiliation(s)
- Robert Adams
- Swiss Federal Institute of Technology, Department of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zürich, Switzerland.
| | - Robert Zboray
- Paul Scherrer Institut, Nuclear Energy and Safety Research Department, 5232 Villigen PSI, Switzerland
| | - Marco Cortesi
- Swiss Federal Institute of Technology, Department of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zürich, Switzerland; Paul Scherrer Institut, Nuclear Energy and Safety Research Department, 5232 Villigen PSI, Switzerland
| | - Horst-Michael Prasser
- Swiss Federal Institute of Technology, Department of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zürich, Switzerland; Paul Scherrer Institut, Nuclear Energy and Safety Research Department, 5232 Villigen PSI, Switzerland
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