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Journal Articles

Characteristics of radiation-resistant real-time neutron monitor for accelerator-based BNCT

Nakamura, Takemi; Sakasai, Kaoru; Nakashima, Hiroshi; Takamiya, Koichi*; Kumada, Hiroaki*

Journal of Radiation Protection and Research, 41(2), p.105 - 109, 2016/06

no abstracts in English

JAEA Reports

Development of breast cancer irradiation technique for BNCT at JRR-4

Nakamura, Takemi; Horiguchi, Hironori; Yanagie, Hironobu*; Arai, Masaji

JAEA-Technology 2014-016, 61 Pages, 2014/06

JAEA-Technology-2014-016.pdf:30.48MB

In the department of research reactor and tandem accelerator, developments of irradiation technique with application enlargement for breast cancer on BNCT have been performed in the second medium term plans. We compiled this report about the technological development to solve several problems with the irradiation of breast cancer in the medical irradiation facility of JRR-4. In the present study, design fabrication of a collimator for breast cancer, dose evaluation analysis by clinical model, investigation of dose enhancement at deeper region and investigation of fixing method for breast cancer irradiation were studied. By these evaluation results, we verified that the developed breast cancer irradiation technique can be applied to BNCT medical irradiation of JRR-4. These results are expected to be able to contribute to breast cancer irradiation techniques of other reactor-based BNCT and future accelerator-based BNCT.

Journal Articles

Numerical simulation of thermohydraulic characteristics of dross ejection process in laser steel cutting

Sugihara, Kenta; Nakamura, Yasuyuki; Ogawa, Takemitsu; Muramatsu, Toshiharu

Proceedings of 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference (ICONE-20 & POWER 2012) (DVD-ROM), 7 Pages, 2012/07

Numerical simulation code, based on multi-phase thermohydraulics, has been being developed with a goal of a control and prediction for the laser cutting process. A thermohydraulic numerical simulation of the laser steel cutting was carried out to confirm an assist gas and sweep velocity effect to the cutting performance. The performance was evaluated, based on temperature profile and cutting front formation. Simulation results were as follows. If there was no effect of dross ejection by assist gas, a laser light was absorbed into molten steel stagnated in the kerf. Therefore, there was less laser heat input to a solid surface directly. Then, heat transport to the back side of steel plate got delayed. In the case of faster sweep velocity, delay of heat conduction and failure cut were confirmed at behind the cut starting position of the steel plate. Failure cut at the position was observed in our experiments. From these results, it was concluded that the thermohydraulics in the kerf takes important role for not only dross ejection but also promotion of heat input at solid surface.

JAEA Reports

Characteristics measurement of JRR-4 neutron beam facility; Accuracy estimation of BNCT dose calculation after change of reflector

Horiguchi, Hironori; Nakamura, Takemi; Motohashi, Jun; Kashimura, Takanori; Ichimura, Shigeju; Sasajima, Fumio

JAEA-Technology 2012-003, 38 Pages, 2012/03

JAEA-Technology-2012-003.pdf:2.55MB

Clinical trials of boron neutron capture therapy (BNCT) for malignant brain tumors and head and neck cancers have been performed at the research reactor JRR-4. BNCT is a kind of radiation therapy using a nuclear reaction with thermal neutrons and boron ($$^{10}$$B) elements administered to a patient. The design specifications of all types of reflector elements were changed due to a trouble of a reflector element in JRR-4. In the production of the new reflector elements, they were designed with the influence for the neutron beam facility by the analytical calculation. After the installation of the new reflector elements, the performance of the neutron beam facility was verified by measurement such as a free air experiment and a water phantom experiment. The calculation error used in the treatment planning for BNCT can be estimated by comparing the results of our calculation with the corresponding experimental data.

Journal Articles

Investigation of irradiation conditions for recurrent breast cancer in JRR-4

Horiguchi, Hironori; Nakamura, Takemi; Kumada, Hiroaki*; Yanagie, Hironobu*; Suzuki, Minoru*; Sagawa, Hisashi

Proceedings of 14th International Congress on Neutron Capture Therapy (ICNCT-14) (CD-ROM), p.234 - 237, 2010/10

Recurrent breast cancer has been considered the application for boron neutron capture therapy using the JRR-4. The investigation of irradiation conditions for the recurrent breast cancer was performed by simulation with the JCDS. We performed the preliminary dosimetry of the model to verify the efficient irradiation conditions such as the neutron energy modes and multiple field technique. From the result, when the 30 Gy-Eq dose as minimum dose was delivered to the cancers, comparable dose distribution was delivered at the healthy tissues by both a one-port irradiation from anterior direction and a two-port irradiation from tangential direction. We revealed that the two-port irradiation was not valid to reduce the healthy tissues dose due to the isotopic scattering of neutrons in the body. We concluded that the optimal irradiation condition was the one-port irradiation with thermal neutron beam mode in terms of less healthy tissues dose and shorter irradiation time.

Journal Articles

Resumption of JRR-4 and characteristics of the neutron beam for BNCT

Nakamura, Takemi; Horiguchi, Hironori; Kishi, Toshiaki; Motohashi, Jun; Sasajima, Fumio; Kumada, Hiroaki*

Proceedings of 14th International Congress on Neutron Capture Therapy (ICNCT-14) (CD-ROM), p.379 - 382, 2010/10

The clinical trials of BNCT have been conducted using JRR-4. The JRR-4 stopped in January 2008, because the graphite reflector was considerably damaged. For this reason, the specifications of graphite reflectors were renewal. All existing graphite reflectors of JRR-4 were changed by new graphite reflectors. The resumption of JRR-4 was carried out with new graphite reflectors in February 2010. We measured the characteristics of neutron beam at the JRR-4 Neutron Beam Facility. A cylindrical water phantom was put the gap for 1cm from the beam port. TLD and gold wire were inserted within the phantom when the phantom was irradiated. The results of the measured thermal neutron flux and the $$gamma$$ dose in water were compared with MCNP calculations. The calculated results showed the same tendency with the experimental results. These results are proceeding well and will be reported in full paper at July 2010.

Journal Articles

Multistep lattice-voxel method utilizing lattice function for Monte-Carlo treatment planning with pixel based voxel model

Kumada, Hiroaki*; Saito, Kimiaki; Nakamura, Takemi; Sakae, Takeji*; Sakurai, Hideyuki*; Matsumura, Akira*; Ono, Koji*

Proceedings of 14th International Congress on Neutron Capture Therapy (ICNCT-14) (CD-ROM), p.238 - 241, 2010/10

Journal Articles

Characteristics measurement of thermal neutron filter developed for improvement of therapeutic dose distribution of JRR-4

Kumada, Hiroaki*; Nakamura, Takemi; Horiguchi, Hironori; Matsumura, Akira*

Proceedings of 14th International Congress on Neutron Capture Therapy (ICNCT-14) (CD-ROM), p.414 - 417, 2010/10

Journal Articles

Feasible evaluation of neutron capture therapy for hepatocellular carcinoma using selective enhancement of boron accumulation in tumour with intra-arterial administration of boron-entrapped water-in-oil-in-water emulsion

Yanagie, Hironobu*; Kumada, Hiroaki*; Nakamura, Takemi; Higashi, Shushi*; Ikushima, Ichiro*; Morishita, Yasuyuki*; Shinohara, Atsuko*; Fujiwara, Mitsuteru*; Suzuki, Minoru*; Sakurai, Yoshinori*; et al.

Proceedings of 14th International Congress on Neutron Capture Therapy (ICNCT-14) (CD-ROM), p.157 - 160, 2010/10

Journal Articles

Performance measurement of the scintillator with optical fiber detector for boron neutron capture therapy

Komeda, Masao; Kumada, Hiroaki; Ishikawa, Masayori*; Nakamura, Takemi; Yamamoto, Kazuyoshi; Matsumura, Akira*

Applied Radiation and Isotopes, 67(7-8, Suppl.), p.S254 - S257, 2009/07

 Times Cited Count:3 Percentile:26.15(Chemistry, Inorganic & Nuclear)

Journal Articles

Performance measurement of the SOF detector for boron neutron capture therapy

Komeda, Masao; Kumada, Hiroaki; Ishikawa, Masayori*; Nakamura, Takemi; Yamamoto, Kazuyoshi; Matsumura, Akira*

Proceedings of 13th International Congress on Neutron Capture Therapy (ICNCT-13) (CD-ROM), 3 Pages, 2008/11

In this report, deterioration of a SOF detector that can measure thermal neutron in real time was investigated in irradiation experiments. Sensitivity of a SOF detector decreased by 2.0% after an irradiation of about 4 hours. Then thermal neutron fluence was approximately 2.0$$times$$10$$^{13}$$ (n/cm$$^{2}$$). And after the SOF detector was used for about 2 months, sensitivity decreased to 42%. Then thermal neutron fluence was approximately 6.4$$times$$10$$^{14}$$ (n/cm$$^{2}$$). Supposing that thermal neutron fluence is 2$$times$$10$$^{12}$$ (n/cm$$^{2}$$) on the surface of a patient at a BNCT, sensitivity of a SOF detector is considered to be decreased by approximately 0.3% at a BNCT. Therefore it is considered that countermeasure against deterioration is necessary for using a SOF detector at BNCT in the future.

Journal Articles

Characteristic of thermal neutron flux distribution in phantom with extended collimator developed for head and neck cancer

Nakamura, Takemi; Kumada, Hiroaki; Kishi, Toshiaki

Proceedings of 12th International Congress on Neutron Capture Therapy (ICNCT-12), p.535 - 538, 2006/10

no abstracts in English

Journal Articles

Dose evaluation in criticality accident conditions using transient critical facilities fueled with a fissile solution

Nakamura, Takemi*; Tonoike, Kotaro; Miyoshi, Yoshinori

Radiation Protection Dosimetry, 110(1-4), p.483 - 486, 2004/09

 Times Cited Count:2 Percentile:17.98(Environmental Sciences)

Dose measurement and evaluation technique in criticality accident conditions with a thermo luminescence dosimeter (TLD) was studied at the Transient Experiment Critical Facility (TRACY) of Japan Atomic Energy Research Institute (JAERI). The tissue absorbed dose can be derived from the ambient dose equivalent given by measurement with a TLD using the conversion factor given by computation. Using this technique, the neutron dose around the SILENE reactor of the Institute for Radioprotection and Nuclear Safety (IRSN) of France was measured in the Accident Dosimetry Intercomparison Exercise (June 10-21, 2002) organized by OECD/NEA and IRSN. In this exercise, the $$gamma$$ dose was also measured with a TLD. In this report, measurements and evaluation results at TRACY and SILENE are presented.

Journal Articles

Power profile evaluation of the JCO precipitation vessel based on the record of the $$gamma$$-ray monitor

Tonoike, Kotaro; Nakamura, Takemi*; Yamane, Yuichi; Miyoshi, Yoshinori

Nuclear Technology, 143(3), p.364 - 372, 2003/09

 Times Cited Count:2 Percentile:19.75(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Analytical evaluation of dose measurement of critical accident at SILENE (Contract research)

Nakamura, Takemi*; Tonoike, Kotaro; Miyoshi, Yoshinori

JAERI-Tech 2003-031, 38 Pages, 2003/03

JAERI-Tech-2003-031.pdf:3.97MB

Institute for Radioprotection and Nuclear Safety (IRSN) and the OECD Nuclear Energy Agency (NEA) jointly organized SILENE Accident Dosimetry Intercomparison Exercise to intercompare the dose measurement systems of participating countries. Each participating country carried out dose measurements in the same irradiation field, and the measurement results were mutually compared. The authors participated in the exercise to measure the doses of gamma rays and neutron from SILENE by using thermoluminescence dosimeters (TLD's) and an alanine dosimeter. In this examination, the authors derived evaluation formulae for obtaining a tissue-absorbed dose from measured value (ambient dose equivalent) of TLD for neutron. We reported the tissue-absorbed dose computed using this evaluation formula to OECD/NEA. TLD's for neutron were irradiated in the TRACY facility to verify the evaluation formulae. The results of TLD's were compared with the calculations of MCNP and measurements with alanine dose meter. We found that the ratio of the dose by the evaluation formula to the measured value by the alanine dosimeter was 0.94 and the formula agreed within 6%. From examination of this TRACY, we can conclude that the value reported to OECD/NEA has equivalent accuracy.

JAEA Reports

Estimation of biases for inserted reactivity estimation of JCO criticality accident

Yamamoto, Toshihiro; Nakamura, Takemi*; Miyoshi, Yoshinori

JAERI-Data/Code 2001-001, 30 Pages, 2001/02

JAERI-Data-Code-2001-001.pdf:1.53MB

no abstracts in English

Journal Articles

Fission source convergence of Monte Carlo criticality calculations in weakly coupling fissile arrays

Yamamoto, Toshihiro; Nakamura, Takemi*; Miyoshi, Yoshinori

Journal of Nuclear Science and Technology, 37(1), p.41 - 52, 2000/01

no abstracts in English

JAEA Reports

Preparation of dosimetry code for static experiment critical facility STACY (Contract research)

Sakurai, Kiyoshi; Miyoshi, Yoshinori; Nakamura, Takemi*; Sato, Osamu*

JAERI-Data/Code 99-021, 99 Pages, 1999/03

JAERI-Data-Code-99-021.pdf:3.03MB

no abstracts in English

Oral presentation

Implementation system for medical irradiation in research reactor (JRR-4)

Yamashita, Kiyonobu; Hori, Naohiko; Kishi, Toshiaki; Nakamura, Takemi; Kumada, Hiroaki

no journal, , 

no abstracts in English

Oral presentation

Performance of miniature thermal neutron monitor for real-time dosimetry for boron neutron capture therapy

Kumada, Hiroaki; Ishikawa, Masayori*; Komeda, Masao; Nakamura, Takemi; Yamamoto, Kazuyoshi; Nakagawa, Yoshinobu*

no journal, , 

no abstracts in English

49 (Records 1-20 displayed on this page)