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Journal Articles

Analysis of two forms of radioactive particles emitted during the early stages of the Fukushima Dai-ichi Nuclear Power Station accident

Satou, Yukihiko; Sueki, Keisuke*; Sasa, Kimikazu*; Yoshikawa, Hideki; Nakama, Shigeo; Minowa, Haruka*; Abe, Yoshinari*; Nakai, Izumi*; Ono, Takahiro*; Adachi, Koji*; et al.

Geochemical Journal, 52(2), p.137 - 143, 2018/00

 Times Cited Count:65 Percentile:97.21(Geochemistry & Geophysics)

Journal Articles

Investigation of the chemical characteristics of individual radioactive microparticles emitted from reactor 1 by the Fukushima Daiichi Nuclear Power Plant accident by using multiple synchrotron radiation X-ray analyses

Ono, Takahiro*; Iizawa, Yushin*; Abe, Yoshinari*; Nakai, Izumi*; Terada, Yasuko*; Satou, Yukihiko; Sueki, Keisuke*; Adachi, Koji*; Igarashi, Yasuhito*

Bunseki Kagaku, 66(4), p.251 - 261, 2017/04

 Times Cited Count:32 Percentile:79.36(Chemistry, Analytical)

no abstracts in English

Journal Articles

The Analysis of boron micro-distribution in 9L gliosarmoma cells and HUVEC cells using PIXE and PIGE

Endo, Kiyoshi*; Shibata, Yasushi*; Yamamoto, Tetsuya*; Nakai, Kei*; Matsumura, Akira*; Sato, Takahiro; Yokoyama, Akihito; Koka, Masashi; Okubo, Takeru; Yamazaki, Akiyoshi; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 86, 2012/01

Journal Articles

Effect of the laser contrast ratio within picosecond timescales on generating a high-quality electron beam by laser-plasma interaction

Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Kameshima, Takashi*; Kawase, Keigo*; Chen, L. M.*; Fukuda, Yuji; Koga, J. K.; Kiriyama, Hiromitsu; Kondo, Shuji; et al.

Japanese Journal of Applied Physics, 50(6), p.066401_1 - 066401_3, 2011/06

 Times Cited Count:1 Percentile:4.8(Physics, Applied)

Journal Articles

Electron optical injection with head-on and countercrossing colliding laser pulses

Kotaki, Hideyuki; Daito, Izuru; Kando, Masaki; Hayashi, Yukio; Kawase, Keigo; Kameshima, Takashi*; Fukuda, Yuji; Homma, Takayuki; Ma, J.*; Chen, L. M.*; et al.

Physical Review Letters, 103(19), p.194803_1 - 194803_4, 2009/11

 Times Cited Count:55 Percentile:88.11(Physics, Multidisciplinary)

Journal Articles

Contrast effect on the laser injected electron beam

Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Homma, Takayuki; Kameshima, Takashi; Kawase, Keigo; Chen, L.-M.*; Fukuda, Yuji; Kiriyama, Hiromitsu; Kondo, Shuji; et al.

AIP Conference Proceedings 1153, p.176 - 181, 2009/07

Journal Articles

"J-KAREN"; High intensity laser

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya*; Tanoue, Manabu*; Akutsu, Atsushi; Okada, Hajime; Motomura, Tomohiro*; Kondo, Shuji; Kanazawa, Shuhei; et al.

JAEA-Conf 2008-007, p.13 - 16, 2008/08

One of the main bottlenecks for the applications of ultrashort and ultrahigh-peak power lasers in high-field physics is a temporal contrast of the pulses. In ultrahigh-peak power lasers, a nanosecond background of the amplified spontaneous emission (ASE) is generated at the same time as the femtosecond pulse. This background is mostly generated in the preamplifier (regenerative, multipass amplifier). Even though the contrast level is usually in the range from 10$$^{-5}$$ to 10$$^{-6}$$, this level is not sufficiently low at relativistic intensities greater than 10$$^{18} $$W/cm$$^{2}$$ to avoid unwanted pre-plasmas generation. We demonstrated a high-contrast, high-peak power laser with optical parametric chirped-pulse amplification (OPCPA). With the use of OPCPA, contrast is enhanced to better than 7$$times$$10$$^{-9}$$ in a few picoseconds before the main pulse, which corresponds to an improvement of three to four orders in magnitude compared with conventional systems.

Journal Articles

Failure patterns of high-grade glioma treated with BNCT

Matsuda, Masahide*; Yamamoto, Tetsuya*; Nakai, Kei*; Endo, Kiyoshi*; Kumada, Hiroaki; Kageji, Teruyoshi*; Matsumura, Akira*

Proceedings of 12th International Congress on Neutron Capture Therapy (ICNCT-12), p.40 - 42, 2006/10

To describe the failure patterns and survival seen with high-grade glioma treated with BNCT, the dose distribution and the clinical responses were retrospectively analyzed. BSH-based BNCT was performed in 12 patients with high-grade glioma (grade IV 7, grade III 5). The post-diagnosis median survival time of 12 patients was 19.8 months (range 3.3-47.2). Four cases of local control, 3 of local recurrence, 3 of distant intraparenchymal recurrence and 2 of subarachnoid dissemination were recorded. According to the analysis of the failure patterns, minimum GTV dose of 26 GyEq or more is necessary for local control.

Journal Articles

Opacity effect on extreme ultraviolet radiation from laser-produced tin plasmas

Fujioka, Shinsuke*; Nishimura, Hiroaki*; Nishihara, Katsunobu*; Sasaki, Akira; Sunahara, Atsushi*; Okuno, Tomoharu*; Ueda, Nobuyoshi*; Ando, Tsuyoshi*; Tao, Y.*; Shimada, Yoshinori*; et al.

Physical Review Letters, 95(23), p.235004_1 - 235004_4, 2005/12

 Times Cited Count:144 Percentile:95.59(Physics, Multidisciplinary)

no abstracts in English

JAEA Reports

Estimation methods of blood boron concentration and error evaluation during boron neutron capture therapy for malignant brain tumor

Shibata, Yasushi*; Yamamoto, Kazuyoshi; Matsumura, Akira*; Yamamoto, Tetsuya*; Hori, Naohiko; Kishi, Toshiaki; Kumada, Hiroaki; Akutsu, Hiroyoshi*; Yasuda, Susumu*; Nakai, Kei*; et al.

JAERI-Research 2005-009, 41 Pages, 2005/03

JAERI-Research-2005-009.pdf:1.99MB

The measurement of neutron flux and boron concentration in the blood during medical irradiation is indispensable in order to evaluate the radiation in boron neutron capture therapy. It is, however, difficult to measure the blood boron concentration during neutron irradiation because access to the patient is limited. Therefore we prospectively investigated the predictability of blood boron concentrations using the data obtained at the first craniotomy after infusion of a low dosage of BSH. When the test could not be carried out, the blood boron concentration during irradiation was also predicted by using the 2-compartment model. If the final boron concentration after the end of the infusion is within 95% confidence interval of the prediction, direct prediction from biexponential fit will reduce the error of blood boron concentrations during irradiation to around 6%. If the final boron concentration at 6 or 9 hours after the end of infusion is out of 95% confidence interval of the prediction, proportional adjustment will reduce error and expected error after adjustment to around 12%.

Journal Articles

Combination of boron and gadolinium compounds for neutron capture therapy; An $$in Vitro$$ study

Matsumura, Akira*; Zhang, T.*; Nakai, Kei*; Endo, Kiyoshi*; Kumada, Hiroaki; Yamamoto, Tetsuya*; Yoshida, Fumiyo*; Sakurai, Yoshinori*; Yamamoto, Kazuyoshi; Nose, Tadao*

Journal of Experimental and Clinical Cancer Research, 24(1), p.93 - 98, 2005/03

no abstracts in English

Journal Articles

Characterization of extreme ultraviolet emission from laser-produced spherical tin plasma generated with multiple laser beams

Shimada, Yoshinori*; Nishimura, Hiroaki*; Nakai, Mitsuo*; Hashimoto, Kazuhisa*; Yamaura, Michiteru*; Tao, Y.*; Shigemori, Keisuke*; Okuno, Tomoharu*; Nishihara, Katsunobu*; Kawamura, Toru*; et al.

Applied Physics Letters, 86(5), p.051501_1 - 051501_3, 2005/01

 Times Cited Count:111 Percentile:94.28(Physics, Applied)

no abstracts in English

Journal Articles

Improvement of dose calculation accuracy for BNCT dosimetry by the multi-voxel method in JCDS

Kumada, Hiroaki; Yamamoto, Kazuyoshi; Yamamoto, Tetsuya*; Nakai, Kei*; Nakagawa, Yoshinobu*; Kageji, Teruyoshi*; Matsumura, Akira*

Applied Radiation and Isotopes, 61(5), p.1045 - 1050, 2004/11

 Times Cited Count:11 Percentile:58.63(Chemistry, Inorganic & Nuclear)

To carry out the BNCT clinical trials based on accurate dosimetry of several absorbed doses given to a patient, we have developed JCDS which can determine the absorbed doses by numerical simulation. The aim of this study is to improve the accuracy of the BNCT dosimetry efficiently. We have developed the multi-voxel calculation method reconstructing the original voxel model by combining of several voxel cell sizes such as in 5mm, 10mm and 20mm voxel cell. To verify the accuracy of the multi-voxel method, the calculation results were compared with the phantom experimental data. These results proved that the multi-voxel calculation enables JCDS to more accurately estimate the absorbed doses to a patient by efficient calculations.

Journal Articles

Current clinical results of the Tsukuba BNCT trial

Yamamoto, Tetsuya*; Matsumura, Akira*; Nakai, Kei*; Shibata, Yasushi*; Endo, Kiyoshi*; Sakurai, Fumio; Kishi, Toshiaki; Kumada, Hiroaki; Yamamoto, Kazuyoshi; Torii, Yoshiya

Applied Radiation and Isotopes, 61(5), p.1089 - 1093, 2004/11

 Times Cited Count:53 Percentile:94.47(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Enhancement of sodium borocaptate (BSH) uptake by tumor cells induced by glutathione depletion and its radiobiological effect

Yoshida, Fumiyo*; Matsumura, Akira*; Yamamoto, Tetsuya*; Kumada, Hiroaki; Nakai, Kei*

Cancer Letters, 215(1), p.61 - 67, 2004/11

 Times Cited Count:13 Percentile:22.52(Oncology)

Sodium borocaptate (BSH) is widely used for Boron Neutron Capture Therapy (BNCT) of brain tumors. However, the mechanism of uptake by the tumor remains unclear. We investigated the sulfhydryl moiety of this compound. Down regulation of glutathione (GSH) by buthionine sulfoximine (BSO) in cultured cells resulted in increase of BSH uptake (7.9 %-36.5 %) compared to control group and subsequently cytocidal effect of neutron irradiation also increased. The radiation damage by $$gamma$$-ray irradiation was suppressed by enhancement of BSH uptake. These findings suggested that modulation of GSH induce enhancement effect of B(n,$$alpha$$) reaction and protective effect of secondary $$gamma$$-ray in BNCT.

Journal Articles

Application of invasion mathematical model in dosimetry for boron neutron capture therapy for malignant glioma

Yamamoto, Kazuyoshi; Kumada, Hiroaki; Nakai, Kei*; Endo, Kiyoshi*; Yamamoto, Tetsuya*; Matsumura, Akira*

Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 14 Pages, 2004/10

A dose distribution considered the tumor cell density distribution is required on the radiation therapy. We propose a novel method of determining target region considering the tumor cell concentration as a new function for the next generation Boron Neutron Capture Therapy (BNCT) dosimetry system. It has not been able to sufficiently define the degree of microscopic diffuse invasion of the tumor cells peripheral to a tumor bulk in malignant glioma using current medical imaging. Referring to treatment protocol of BNCT, the target region surrounding the tumor bulk has been set as the region which expands at the optional distance with usual 2cm margin from the region enhanced on T1 weighted gadolinium Magnetic Resonance Imaging (MRI). In this research, the cell concentration of the region boundary of the target was discussed by using tumor cell diffusion model in the sphere spatio-temporal system. The survival tumor cell density distribution after the BNCT irradiation was predicted by the two regions diffusion model for a virtual brain phantom.

Journal Articles

Analysis of intracellular distribution of boron and gadolinium in 9L sarcoma cells using a single-ended accelerator (Micro PIXE)

Endo, Kiyoshi*; Shibata, Yasushi*; Yoshida, Fumiyo*; Nakai, Kei*; Yamamoto, Tetsuya*; Matsumura, Akira*; Ishii, Keizo*; Sakai, Takuro; Sato, Takahiro; Oikawa, Masakazu*; et al.

Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 2 Pages, 2004/10

Micro PIXE, which is installed in a single end accelerator in JAERI, was used for quantitative analysis of boron and gadolinium distribution in a cell level. The micro beam of 1 $$mu$$m diameter is possible to observe the distribution. In the adjustment procedure of the sample, first is a fix of mylar film by using a glass ring and a bite ring of 2cm diameter. Next the 9L cells were scattered on the washed film, and is cultivated on 37$$^{circ}$$C in medium until they form the mono-layer. After the Gd-BOPTA was added, it incubates for the 24-72 hour on 37$$^{circ}$$C. The film is washed in the THAM liquid, and is directly put on liquid nitrogen. A vacuum drying for 24 hours is conducted in order to fix a film on holder. It is important to uniformly fix the cell in distribution analysis in the cell using Micro PIXE. In recent result, it became possible that the distribution of P, S, Gd, etc. was analyzed. But we could not distinguish whether K and Gd exist in the cell or whether it exists around the cell. It was indicated that these elements was leaked by the reason of cell breaking or other on the cytoplasm.

Journal Articles

The Prediction of Boron concentrations in blood for patients of boron neutron capture therapy, 2

Shibata, Yasushi*; Matsumura, Akira*; Yamamoto, Tetsuya*; Akutsu, Hiroyoshi*; Yasuda, Susumu*; Nakai, Kei*; Nose, Tadao*; Yamamoto, Kazuyoshi; Kumada, Hiroaki; Hori, Naohiko; et al.

Research and Development in Neutron Capture Therapy, p.1055 - 1060, 2002/09

We prospectively investigated the predictability of blood boron concentrations using the data obtained at the first craniotomy after infusion of a low dose of sodium undecahydroclosododecaborate (BSH). Nine patients with malignant glial tumors underwent Boron neutron capture therapy (BNCT) at the Japan Atomic Energy Research Institute (JAERI) between 1995 and 2001. In 7 patients, 1g of BSH was infused before the first tumor removal and boron concentrations were determined using prompt gamma ray analysis (PGA). Then, 12 hours before BNCT, patients were infused at a dose of 100mg/kg BSH, and the boron concentrations were determined again. The boron biodistribution data showed a biexponential pharmacokinetic profile. If the final boron concentration at 6 or 9 hours after the end of the infusion is within the 95% confidence interval of the prediction, direct prediction from biexponential fit will reduce the error of blood boron concentrations during irradiation to around 6%.

Journal Articles

Phase I/II clinical trial of boron neutron capture therapy using mixed thermal/epithermal neutron beam

Matsumura, Akira*; Yamamoto, Tetsuya*; Shibata, Yasushi*; Nakai, Kei*; Zhang, T.*; Akutsu, Hiroyoshi*; Matsushita, Akira*; Yasuda, Susumu*; Takano, Shingo*; Nose, Tadao*; et al.

Posuto Shikuensu Jidai Ni Okeru Noshuyo No Kenkyu To Chiryo, p.427 - 435, 2002/07

no abstracts in English

Journal Articles

Basic and clinical studies for application of epithermal neutron beam for neutron capture therapy

Nose, Tadao*; Matsumura, Akira*; Yamamoto, Tetsuya*; Shibata, Yasushi*; Yoshida, Fumiyo*; Akutsu, Hiroyoshi*; Yasuda, Susumu*; Matsushita, Akira*; Nakai, Kei*; Yamada, Takashi*; et al.

UTRCN-G-29, p.114 - 123, 2001/00

no abstracts in English

36 (Records 1-20 displayed on this page)