External dose evaluation based on detailed air dose rate measurements in living environments

Sato, Tetsuro*; Ando, Masaki; Sato, Masako*; Saito, Kimiaki

Journal of Environmental Radioactivity, 210, p.105973_1 - 105973_7, 2019/12

https://doi.org/10.1016/j.jenvrad.2019.05.005

A method was devised for estimation of external doses of Fukushima residents expected to return to their homes after evacuation orders are lifted. 211 residents expected to return to six towns and villages were surveyed in FY 2014, FY 2015, and FY2016. Interviewing returning residents about their expected life patterns after returning, air dose rate were measured along the reported personal trails representing their patterns of movement in daily life. Excluding 15 residents from whose homes we were unable to take air dose rate measurements, the maximum external effective dose and the average external effective dose were estimated respectively as 4.9 mSv/y and 0.86 mSv/y. Although the mean values and dispersion of external effective doses differ depending on the evacuation level, for 93.3% of all residents, the estimated external effective doses were less than 2 mSv/y. The average exposure dose at home accounts for 66.8% of the annual exposure dose.

Application of Cu produced by Zn()Cu to biodistribution study in tumor-bearing mice

Sugo, Yumi*; Hashimoto, Kazuyuki*; Kawabata, Masako*; Saeki, Hideya*; Sato, Shunichi*; Tsukada, Kazuaki; Nagai, Yasuki*

Journal of the Physical Society of Japan, 86(2), p.023201_1 - 023201_3, 2017/02

https://doi.org/10.7566/JPSJ.86.023201

Cu produced by the Zn()Cu reaction was used for the first time to determine the biodistribution of CuCl in colorectal tumor-bearing mice. High uptake of Cu was observed in the tumor as well as in the liver and kidney which are the major organs for copper metabolism. The result showing Cu accumulation in the tumor suggests that CuCl can be a potential radionuclide agent for cancer radiotherapy. It would also encourage further studies on the therapeutic effect in small animals using an increased dose of Cu produced by the Zn()Cu reaction using intense neutrons available at present.

New phenomenon observed in thermal release of Tc from molten MoO

Kawabata, Masako; Nagai, Yasuki; Hashimoto, Kazuyuki; Saeki, Hideya; Motoishi, Shoji*; Sato, Nozomi*; Ota, Akio*; Shiina, Takayuki*; Kawauchi, Yukimasa*

Journal of the Physical Society of Japan, 84(2), p.023201_1 - 023201_4, 2015/02

https://doi.org/10.7566/JPSJ.84.023201

Tc for medical use can be separated by thermochromatography from a molten MoO sample. Effect of moist oxygen gas on the Tc release from molten MoO samples was investigated using a Mo/Tc generator. Mo was produced with Mo(n,2n)Mo. A new phenomenon has been observed: release rate, separation- and recovery-efficiencies of Tc were higher in the moist oxygen gas than those in the dry oxygen gas. The present result is a significant progress towards the stable production of a high quality Tc from a molten MoO sample with high separation efficiency. The result would also give us a new insight into the interaction between the moist oxygen gas and the molten MoO.

First measurement of the radionuclide purity of the therapeutic isotope Cu produced by Z(,) reaction using C(,) neutrons

Sato, Nozomi; Tsukada, Kazuaki; Watanabe, Satoshi; Ishioka, Noriko; Kawabata, Masako; Saeki, Hideya; Nagai, Yasuki; Kin, Tadahiro*; Minato, Futoshi; Iwamoto, Nobuyuki; et al.

Journal of the Physical Society of Japan, 83(7), p.073201_1 - 073201_4, 2014/07

https://doi.org/10.7566/JPSJ.83.073201

We have for the first time demonstrated that the therapeutic nuclide of Cu produced by Zn(,)Cu has highest radionuclide purity compared to previous ones. We measured a -ray spectrum of the reaction product produced by bombarding an enriched Zn sample with neutrons with a HPGe detector. The neutrons were obtained by C(,) using 41 MeV deuterons provided from Takasaki Ion Accelerators for Advanced Radiation Application of Japan Atomic Energy Agency. Relative production yields of impurity radionuclides such as Zn to Cu are extremely low, which allow us to chemically separate Cu from an irradiated Zn sample with a few steps and to reuse high cost an enriched Zn sample. The present result strongly suggest that the Zn(,)Cu reaction is the most promising route to produce high quality Cu and could solve a longstanding problem of establishing an appropriate production method of Cu.

Generation of radioisotopes with accelerator neutrons by deuterons

Nagai, Yasuki; Hashimoto, Kazuyuki; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji; Sonoda, Nozomi; Kawabata, Masako; Harada, Hideo; Kin, Tadahiro*; Tsukada, Kazuaki; et al.

Journal of the Physical Society of Japan, 82(6), p.064201_1 - 064201_7, 2013/06

https://doi.org/10.7566/JPSJ.82.064201

Investigation of the survivability of spp. under space

Kawaguchi, Yuko*; Yang, Y.*; Murano, Yuka*; Harada, Miyu*; Kawashiri, Narutoshi*; Shiraishi, Keisuke*; Takasu, Masako*; Narumi, Issey*; Sato, Katsuya; Hashimoto, Hirofumi*; et al.

no journal, , 

no abstracts in English

Analysis of trace elements in lung by in-air micro-PIXE

Okamoto, Masahiko*; Sakurai, Hideyuki*; Shin, Masako*; Hasegawa, Masatoshi*; Oikawa, Masakazu*; Sato, Takahiro; Kamiya, Tomihiro; Arakawa, Kazuo; Nakano, Takashi*

no journal, , 

no abstracts in English

Medical radioisotope production with accelerator neutrons by deuterons

Tsukada, Kazuaki; Sato, Nozomi*; Watanabe, Satoshi; Ishioka, Noriko; Hatsukawa, Yuichi; Hashimoto, Kazuyuki; Kin, Tadahiro*; Takeda, Shinsaku*; Kawabata, Masako; Saeki, Hideya; et al.

no journal, , 

A new system has been proposed for the generation of radioisotopes with accelerator neutrons by deuterons, especially the production of Mo-99, Y-90, Cu-67, and Cu-64. Enriched Mo-100, Zr-90, Zn-68 and Zn-64 oxide samples were irradiated with neutrons, which were obtained by the C(d,n) and Be(d,n) using 40 MeV deuterons provided from the TIARA cyclotron. Mo-99, Y-90, Cu-67, and Cu-64 were successfully produced via the (n, x) reactions, and we clearly observed the -rays. Particularly, yields of impurity radionuclides were much smaller than that of Mo-99 and Cu-67, and therefore radioactive waste produced during chemical processing would be reduced compared with other proposed reaction systems. The present results demonstrate that the radioisotopes, Mo-99, Y-90, Cu-67, and Cu-64, can be produced by using fast neutrons, and strongly suggest that the reaction system is one of the most promising routes to produce high quality medical radioisotope.

Medical radioisotope production with accelerator neutrons by 40 MeV deuterons

Tsukada, Kazuaki; Sato, Nozomi; Watanabe, Satoshi; Ishioka, Noriko; Hatsukawa, Yuichi; Hashimoto, Kazuyuki; Kin, Tadahiro*; Kawabata, Masako; Saeki, Hideya; Nagai, Yasuki

no journal, , 

no abstracts in English

High quality Tc obtained from Mo produced by Mo(n,2n) using accelerator neutrons

Nagai, Yasuki; Kawabata, Masako; Sato, Nozomi*; Hashimoto, Kazuyuki; Saeki, Hideya; Motoishi, Shoji*; Hatsukawa, Yuichi; Ota, Akio; Shiina, Takayuki; Kawauchi, Yukimasa

no journal, , 

Tc, the daughter nuclide of Mo, is widely used for medical diagnosis. In Japan, about 0.9 million diagnostic procedures are carried out using Tc. Mo has been mostly produced using U in research reactors. Because of recent shortages of Mo, a variety of alternative production methods of Mo or Tc were proposed. We proposed to produce Mo by Mo(n,2n) using neutrons from an accelerator. The route is characterized to produce a large quantity of high-quality Mo with a minimum level of radioactive wastes, since the cross section of the Mo(n,2n)Mo reaction at 11 En 18 MeV is large, and the cross sections of the (n,He), (n,n'p), and (n,p) reactions on Mo are quite small. Intense neutrons are available because of recent progresses of accelerator and target technologies. In the talk, we show our recent experimental results to obtain Tc with high-quality using Mo produced by Mo(n,2n).