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Sohrabi M, Malekitakbolagh M, Nedaei HA. Breakthrough electroneutron multi-response miniature dosimetry/spectrometry in medical accelerator. Sci Rep 2024; 14:9557. [PMID: 38664481 PMCID: PMC11045717 DOI: 10.1038/s41598-024-59871-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
Breakthrough multi-response miniature dosimetry/spectrometry of electroneutrons (EN) was made on surface and in-depths of whole-body polyethylene phantom under 10 cm × 10 cm electron beam of 20 MV Varian Clinac 2100C electron medical accelerator commonly applied for prostate treatment. While dosimetry/spectrometry of photoneutrons (PN) has been well characterized for decades, those of ENs lagged behind due to very low EN reaction cross section and lack of sensitive neutron dosimeters/spectrometers meeting neutron dosimetry requirements. Recently, Sohrabi "miniature neutron dosimeter/spectrometer" and "Stripe polycarbonate dosimeter" have broken this barrier and determined seven EN ambient dose equivalent (ENDE) (µSv.Gy-1) responses from electron beam and from albedo ENs including beam thermal (21 ± 2.63), albedo thermal (43 ± 3.70), total thermal (64 ± 6.33), total epithermal (32 ± 3.90), total fast (112.00), total thermal + epithermal (l96 ± 10), and total thermal + epithermal + fast (208 ± 10.23) ENs. Having seven ENDE responses of this study and seven PNDE responses of previous study with the same accelerator obtained at identical conditions by the same principle author provided the opportunity to compare the two sets of responses. The PNDE (µSv.Gy-1) responses have comparatively higher values and 22.60 times at isocenter which provide for the first time breakthrough ENDE responses not yet reported in any studies before worldwide.
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Affiliation(s)
- Mehdi Sohrabi
- Health Physics and Dosimetry Research Laboratory, Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran, Iran.
| | - Maryam Malekitakbolagh
- Health Physics and Dosimetry Research Laboratory, Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran, Iran
| | - Hasan Ali Nedaei
- Department of Radiotherapy Oncology, Cancer Institute, University of Medical Sciences, Tehran, Iran
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Oancea C, Solc J, Bourgouin A, Granja C, Jakubek J, Pivec J, Riemer F, Vykydal Z, Worm S, Marek L. Thermal neutron detection and track recognition method in reference and out-of-field radiotherapy FLASH electron fields using Timepix3 detectors. Phys Med Biol 2023; 68:185017. [PMID: 37607560 DOI: 10.1088/1361-6560/acf2e1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 08/22/2023] [Indexed: 08/24/2023]
Abstract
Objective.This work presents a method for enhanced detection, imaging, and measurement of the thermal neutron flux.Approach. Measurements were performed in a water tank, while the detector is positioned out-of-field of a 20 MeV ultra-high pulse dose rate electron beam. A semiconductor pixel detector Timepix3 with a silicon sensor partially covered by a6LiF neutron converter was used to measure the flux, spatial, and time characteristics of the neutron field. To provide absolute measurements of thermal neutron flux, the detection efficiency calibration of the detectors was performed in a reference thermal neutron field. Neutron signals are recognized and discriminated against other particles such as gamma rays and x-rays. This is achieved by the resolving power of the pixel detector using machine learning algorithms and high-resolution pattern recognition analysis of the high-energy tracks created by thermal neutron interactions in the converter.Main results. The resulting thermal neutrons equivalent dose was obtained using conversion factor (2.13(10) pSv·cm2) from thermal neutron fluence to thermal neutron equivalent dose obtained by Monte Carlo simulations. The calibrated detectors were used to characterize scattered radiation created by electron beams. The results at 12.0 cm depth in the beam axis inside of the water for a delivered dose per pulse of 1.85 Gy (pulse length of 2.4μs) at the reference depth, showed a contribution of flux of 4.07(8) × 103particles·cm-2·s-1and equivalent dose of 1.73(3) nSv per pulse, which is lower by ∼9 orders of magnitude than the delivered dose.Significance. The presented methodology for in-water measurements and identification of characteristic thermal neutrons tracks serves for the selective quantification of equivalent dose made by thermal neutrons in out-of-field particle therapy.
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Affiliation(s)
- Cristina Oancea
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
- University of Bucharest, Bucharest, Romania
| | - Jaroslav Solc
- Czech Metrology Institute, Okruzni 31, 638 00 Brno, Czech Republic
| | - Alexandra Bourgouin
- Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, 38116, Germany
| | - Carlos Granja
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
| | - Jan Jakubek
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
| | - Jiri Pivec
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
| | - Felix Riemer
- Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, 15738 Zeuthen, Germany
| | - Zdenek Vykydal
- Czech Metrology Institute, Okruzni 31, 638 00 Brno, Czech Republic
| | - Steven Worm
- Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, 15738 Zeuthen, Germany
| | - Lukas Marek
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
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Vega-Carrillo HR, Soto-Bernal TG. Neutrons produced in a 12 MV LINAC working in electron mode. Radiat Phys Chem Oxf Engl 1993 2023. [DOI: 10.1016/j.radphyschem.2023.110905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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Characterization of photoneutron fluxes emitted by electron accelerators in the 4–20 MeV range using Monte Carlo codes: A critical review. Appl Radiat Isot 2022; 191:110506. [DOI: 10.1016/j.apradiso.2022.110506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/23/2022] [Accepted: 09/30/2022] [Indexed: 11/18/2022]
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Moghaddasi L, Colyer C. Evaluation of the effectiveness of steel for shielding photoneutrons produced in medical linear accelerators: A Monte Carlo particle transport study. Phys Med 2022; 98:53-62. [DOI: 10.1016/j.ejmp.2022.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/13/2022] [Accepted: 04/22/2022] [Indexed: 10/18/2022] Open
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Kakino R, Nakamura M, Hu N, Iramina H, Tanaka H, Sakurai Y, Mizowaki T. Photoneutron-induced damage reduction for cardiac implantable electronic devices using neutron-shielding sheets in high-energy X-ray radiotherapy: A phantom study. Phys Med 2021; 89:151-159. [PMID: 34371340 DOI: 10.1016/j.ejmp.2021.07.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/06/2021] [Accepted: 07/28/2021] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To evaluate damage reduction in cardiac implantable electronic devices (CIEDs) caused by photoneutrons in high-energy X-ray radiotherapy using a neutron-shielding sheet (NSS). METHODS The NSS consists of a bolus with a thickness of 1 or 2 cm (Bls1 or Bls2) as a moderator and several absorbers (20%, 50%, or 80% B4C silicone sheet [B4C20, B4C50, or B4C80] or a 40% LiF silicone sheet [LiF40]). First, a linear accelerator (LINAC) with a water-equivalent phantom was modeled in the simulation and measured experimentally. Several NSSs were placed on the phantom, a Eu:LiCaAlF6 scintillator was placed between the phantom and the NSS, and X-rays were irradiated. The relative counts (Cr = counts when placing the NSS or Bls2) were compared between the experiment and simulation. Second, CIED damage was evaluated in the simulation. The relative damage (Dr = damage when placing or not placing the NSS) was compared among all the NSSs. In addition, the γ-ray and leaking X-ray dose from B4C was measured using a dosimetric film. After determining the optimal NSS combination, Dr value analysis was performed by changing the length of one side and the thickness. RESULTS The Cr values of the simulation and experiment agreed within a 30% percentage difference, except for Bare or LiF40-only. The Dr value was reduced by 43% when Bls2 + B4C80 was applied. The photon dose was less than 5 cGy/1500 MU. The Dr values were smaller for the smaller lengths of one side of B4C80 and decreased as the M-layer thickness increased. CONCLUSIONS The CIED damage induced by photoneutrons generated by a LINAC was effectively reduced by applying the optimal NSS.
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Affiliation(s)
- Ryo Kakino
- Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan; Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan; Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Mitsuhiro Nakamura
- Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan; Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Naonori Hu
- Kansai BNCT Medical Center, Osaka Medical College, 2-7 Daigaku-Machi, Takatsuki, Osaka 569-8686, Japan; Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2 Asashiro-nishi Kumatori-cho, Osaka 590-0494, Japan
| | - Hiraku Iramina
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Hiroki Tanaka
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2 Asashiro-nishi Kumatori-cho, Osaka 590-0494, Japan
| | - Yoshinori Sakurai
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2 Asashiro-nishi Kumatori-cho, Osaka 590-0494, Japan
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
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