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Maeda H, Nohtomi A, Hu N, Kakino R, Akita K, Ono K. Feasibility study of optical imaging of the boron-dose distribution by a liquid scintillator in a clinical boron neutron capture therapy field. Med Phys 2024; 51:509-521. [PMID: 37672219 DOI: 10.1002/mp.16727] [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: 03/27/2023] [Revised: 08/06/2023] [Accepted: 08/23/2023] [Indexed: 09/07/2023] Open
Abstract
BACKGROUND Evaluation of the boron dose is essential for boron neutron capture therapy (BNCT). Nevertheless, a direct evaluation method for the boron-dose distribution has not yet been established in the clinical BNCT field. To date, even in quality assurance (QA) measurements, the boron dose has been indirectly evaluated from the thermal neutron flux measured using the activation method with gold foil or wire and an assumed boron concentration in the QA procedure. Recently, we successfully conducted optical imaging of the boron-dose distribution using a cooled charge-coupled device (CCD) camera and a boron-added liquid scintillator at the E-3 port facility of the Kyoto University Research Reactor (KUR), which supplies an almost pure thermal neutron beam with very low gamma-ray contamination. However, in a clinical accelerator-based BNCT facility, there is a concern that the boron-dose distribution may not be accurately extracted because the unwanted luminescence intensity, which is irrelevant to the boron dose is expected to increase owing to the contamination of fast neutrons and gamma rays. PURPOSE The purpose of this research was to study the validity of a newly proposed method using a boron-added liquid scintillator and a cooled CCD camera to directly observe the boron-dose distribution in a clinical accelerator-based BNCT field. METHOD A liquid scintillator phantom with 10 B was prepared by filling a small quartz glass container with a commercial liquid scintillator and boron-containing material (trimethyl borate); its natural boron concentration was 1 wt%. Luminescence images of the boron-neutron capture reaction were obtained in a water tank at several different depths using a CCD camera. The contribution of background luminescence, mainly due to gamma rays, was removed by subtracting the luminescence images obtained using another sole liquid scintillator phantom (natural boron concentration of 0 wt%) at each corresponding depth, and a depth profile of the boron dose with several discrete points was obtained. The obtained depth profile was compared with that of calculated boron dose, and those of thermal neutron flux which were experimentally measured or calculated using a Monte Carlo code. RESULTS The depth profile evaluated from the subtracted images indicated reasonable agreement with the calculated boron-dose profile and thermal neutron flux profiles, except for the shallow region. This discrepancy is thought to be due to the contribution of light reflected from the tank wall. The simulation results also demonstrated that the thermal neutron flux would be severely perturbed by the 10 B-containing phantom if a relatively larger container was used to evaluate a wide range of boron-dose distributions in a single shot. This indicates a trade-off between the luminescence intensity of the 10 B-added phantom and its perturbation effect on the thermal neutron flux. CONCLUSIONS Although a partial discrepancy was observed, the validity of the newly proposed boron-dose evaluation method using liquid-scintillator phantoms with and without 10 B was experimentally confirmed in the neutron field of an accelerator-based clinical BNCT facility. However, this study has some limitations, including the trade-off problem stated above. Therefore, further studies are required to address these limitations.
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Affiliation(s)
- Hideya Maeda
- Graduate School of Medical Sciences, Kyushu University, Fukuoka-shi, Fukuoka, Japan
| | - Akihiro Nohtomi
- Graduate School of Medical Sciences, Kyushu University, Fukuoka-shi, Fukuoka, Japan
| | - Naonori Hu
- Kansai BNCT Medical Center, Osaka Medical and Pharmaceutical University, Takatsuki-shi, Osaka, Japan
- Particle Radiation Oncology Research Center, Industrial Equipment Division, Kyoto University, Sennan-gun, Osaka, Japan
| | - Ryo Kakino
- Kansai BNCT Medical Center, Osaka Medical and Pharmaceutical University, Takatsuki-shi, Osaka, Japan
| | - Kazuhiko Akita
- Kansai BNCT Medical Center, Osaka Medical and Pharmaceutical University, Takatsuki-shi, Osaka, Japan
| | - Koji Ono
- Kansai BNCT Medical Center, Osaka Medical and Pharmaceutical University, Takatsuki-shi, Osaka, Japan
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Gimenez ML, Lipovetzky J, Alcalde Bessia F, Longhino JM, Tartaglione A, Garcia-Inza MA, Blostein JJ, Carbonetto S, Gómez Berisso M, Pérez M, Sidelnik I, Redin EG, Faigón A. Neutron-gamma dosimetry for BNCT using field oxide transistors with gadolinium oxide as neutron converter layer. Med Phys 2021; 49:1276-1285. [PMID: 34851535 DOI: 10.1002/mp.15385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 11/02/2021] [Accepted: 11/06/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE A new type of electronic dosimeter is presented, capable of discerning between the doses of gamma photons and neutrons in a mixed beam as found in boron neutron capture therapy (BNCT). We introduce a real-time dosimeter based on a thick gate field oxide field effect transistor (FOXFET) covered with a neutron converter layer containing gadolinium. METHODS To sensitize the FOXFET dosimeter to neutron fluxes, a converter layer containing gadolinium oxide particles embedded in photoresines was deposited over the sensor surface. Mixed neutron-gamma field configurations with different neutron energy spectra were used to assess the FOXFET response, considering different thicknesses of the neutron converter layer. RESULTS The total gamma sensitivity of the devices resulted to be 43 mV/Gy. The responses of sensors with different converter layer thicknesses irradiated with different neutron spectra are simulated using GEANT4 code. The response to photons is not significantly modified with thin conversion layers when used in water medium. CONCLUSIONS A real-time dosimeter comprising a pair of FOXFET sensors-only one of them with a gadolinium neutron converter layer-allows the simultaneous measurement of gamma dose and neutron flux during BNCT irradiations.
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Affiliation(s)
- Melisa Lucía Gimenez
- Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina.,Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche, Río Negro, Argentina
| | - José Lipovetzky
- Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina.,Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche, Río Negro, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Fabricio Alcalde Bessia
- Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche, Río Negro, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Juan Manuel Longhino
- Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina.,Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche, Río Negro, Argentina
| | - Aureliano Tartaglione
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße, Garching bei München, Germany
| | - Mariano Andrés Garcia-Inza
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.,Facultad de Ingeniería, Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Juan Jerónimo Blostein
- Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche, Río Negro, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Sebastián Carbonetto
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.,Facultad de Ingeniería, Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Mariano Gómez Berisso
- Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche, Río Negro, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Martín Pérez
- Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina.,Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche, Río Negro, Argentina
| | - Iván Sidelnik
- Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche, Río Negro, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Eduardo Gabriel Redin
- Facultad de Ingeniería, Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Adrián Faigón
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.,Facultad de Ingeniería, Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
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Ishikawa M, Tanaka K, Endo S, Hoshi M. Application of an ultraminiature thermal neutron monitor for irradiation field study of accelerator-based neutron capture therapy. JOURNAL OF RADIATION RESEARCH 2015; 56:391-396. [PMID: 25589504 PMCID: PMC4380057 DOI: 10.1093/jrr/rru112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/04/2014] [Accepted: 11/05/2014] [Indexed: 06/04/2023]
Abstract
Phantom experiments to evaluate thermal neutron flux distribution were performed using the Scintillator with Optical Fiber (SOF) detector, which was developed as a thermal neutron monitor during boron neutron capture therapy (BNCT) irradiation. Compared with the gold wire activation method and Monte Carlo N-particle (MCNP) calculations, it was confirmed that the SOF detector is capable of measuring thermal neutron flux as low as 10(5) n/cm(2)/s with sufficient accuracy. The SOF detector will be useful for phantom experiments with BNCT neutron fields from low-current accelerator-based neutron sources.
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Affiliation(s)
- Masayori Ishikawa
- Department of Medical Physics and Engineering, Graduate School of Medicine, Hokkaido University, N-15 W-7 Kita-ku, Sapporo Hokkaido, 060-8638, Japan
| | - Kenichi Tanaka
- Center of Medical Education, Sapporo Medical University, S-1 W-16 Chuo-ku, Sapporo Hokkaido, 060-8543, Japan
| | - Satrou Endo
- Graduate School of Engineering, Hiroshima University, 1-4-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
| | - Masaharu Hoshi
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi Minami-ku, Hiroshima Hiroshima 734-8553, Japan
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