Nagai, Yasuki*; Kawabata, Masako*; Hashimoto, Shintaro; Tsukada, Kazuaki; Hashimoto, Kazuyuki*; Motoishi, Shoji*; Saeki, Hideya*; Motomura, Arata*; Minato, Futoshi; Ito, Masatoshi*
Journal of the Physical Society of Japan, 91(4), p.044201_1 - 044201_10, 2022/04
Recently, Lu is considered as one of the most important medical RIs for treating neuroendocrine tumors. A plan to produce Lu with high purity by using enriched Yb samples with irradiation of deuteron beams in accelerators has been discussed. However, since the other Yb isotopes contained in the Yb sample interacts with deuterons, Lu isotopes other than Lu are produced as impurities. Since the purity of Lu is important for medical use, a method to evaluate the impurity of Lu has been required. In this study, we proposed a new method to estimate production yields of each Lu isotopes in Yb samples with arbitrary isotopic compositions by using excitation functions of Yb()Lu reactions and the particle transport calculation code PHITS. The method plays an important role in discussing the isotopic composition of enriched samples to produce high-purity Lu using accelerators.
Kawabata, Masako*; Motoishi, Shoji*; Ota, Akio*; Motomura, Arata*; Saeki, Hideya*; Tsukada, Kazuaki; Hashimoto, Shintaro; Iwamoto, Nobuyuki; Nagai, Yasuki*; Hashimoto, Kazuyuki*
Journal of Radioanalytical and Nuclear Chemistry, 330(3), p.913 - 922, 2021/12
Both Cu and Cu are promising radionuclides in nuclear medicine. Production yields of these radionuclides were quantified by irradiating 55.4 g of natural zinc with accelerator neutrons. Clinically suitable Cu and Cu yields were estimated by experimental based numerical simulations using 100 g of enriched Zn and Zn, respectively, and elevated neutron fluxes from 40 MeV, 2 mA deuterons. A combined thermal- and resin-separation method was developed to isolate Cu and Cu from zinc, resulting in 73% separation efficiency and 97% zinc recovery. Such methods can provide large scale production of Cu and Cu for clinical applications.
Nagai, Yasuki*; Kinoshita, Mitsutaka*; Igashira, Masayuki*; Nobuhara, Yuriko*; Makii, Hiroyuki; Mishima, Kenji*; Shima, Tatsushi*; Mengoni, A.*
Physical Review C, 102(4), p.044616_1 - 044616_8, 2020/10
Tsukada, Kazuaki; Nagai, Yasuki*; Hashimoto, Shintaro; Minato, Futoshi; Kawabata, Masako*; Hatsukawa, Yuichi*; Hashimoto, Kazuyuki*; Watanabe, Satoshi*; Saeki, Hideya*; Motoishi, Shoji*
Journal of the Physical Society of Japan, 89(3), p.034201_1 - 034201_7, 2020/03
We found anomalously large yields of Ga, Ga, Zn and Cu by neutron irradiation on a ZnO sample in a polyethylene shield. Neutron beams are generated from the Be() reaction for 50 MeV deuterons. The yields obtained were more than 20 times larger than those in the unshielded sample. On the other hand, the yields of Ga, Ga, Zn and Cu from a metallic Zn sample and the yields of Cu, Ni and Zn from the ZnO and Zn samples were almost insensitive to the shield conditions. This finding would provide us a unique capability of accelerator neutrons to simultaneously produce a large amount of several radioisotopes, including proton induced reaction products, by using a single sample. The experimental data were compared with the yields estimated by using the Particle and Heavy Ion Transport code System and the result was discussed.
Tsukada, Kazuaki; Nagai, Yasuki*; Hashimoto, Kazuyuki*; Kawabata, Masako*; Minato, Futoshi; Saeki, Hideya*; Motoishi, Shoji*; Ito, Masatoshi*
Journal of the Physical Society of Japan, 87(4), p.043201_1 - 043201_5, 2018/04
Minato, Futoshi; Tsukada, Kazuaki; Sato, Nozomi*; Watanabe, Satoshi*; Saeki, Hideya*; Kawabata, Masako*; Hashimoto, Shintaro; Nagai, Yasuki*
Journal of the Physical Society of Japan, 86(11), p.114803_1 - 114803_6, 2017/11
We have measured the yield of Mo, the mother nuclide of Tc used in nuclear diagnostic procedure. Mo was produced by Mo(,)Mo using neutrons with thermal energy up to about 40 MeV, provided by C(,). The Mo yield agrees with an estimated yield with the use of the latest data of C(,) and the evaluated cross section given in the JENDL. Based on this, a new calculation was carried out to produce Mo to seek for a good economical condition. Various conditions such as the MoO sample mass, the distance between the carbon target and the sample, the radius of the deuteron beam, and the neutron irradiation time were considered. The calculated Mo yield indicates that about 30% of the Mo demand in Japan can be fulfilled with a single accelerator. The elusion of Tc from the Mo twice per day would meet about 50% of the Mo demand.
Nagai, Yasuki*; Tsukada, Kazuaki
Isotope News, (753), p.28 - 32, 2017/10
no abstracts in English
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
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.
Hashimoto, Kazuyuki; Nagai, Yasuki; Kawabata, Masako; Sato, Nozomi*; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji*; Ota, Masayuki; Konno, Chikara; Ochiai, Kentaro; et al.
Journal of the Physical Society of Japan, 84(4), p.043202_1 - 043202_4, 2015/04
Hatsukawa, Yuichi; Hashimoto, Kazuyuki; Tsukada, Kazuaki; Sato, Tetsuya; Asai, Masato; Toyoshima, Atsushi; Nagai, Yasuki; Tanimori, Toru*; Sonoda, Shinya*; Kabuki, Shigeto*; et al.
Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1283 - 1285, 2015/02
Technetium-99m (Tc) is used in radioactive medical diagonostic tests, for example as a radioactive tracer that medical equipment can detect in the human body. It is well suited to the role because it emits readily detectable 141 keV rays, and its half-life is 6.01 hours (meaning that about 94% of it decays to technetium-99 in 24 hours). There are at least 31 commonly used radiopharmaceuticals based on technetium-99m for imaging and functional studies of the brain, myocardium, thyroid, lungs, liver, gallbladder, kidneys, skeleton, blood, and tumors. Recent years, with the develop-ment of the Compton camera which can realize high position resolution, technetium isotopes emitting high energy -rays are required. In this study, technetium-95m which emits some rays around 800 keV was produced by the Mo(p,n)Tc reaction.
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
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.
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
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.
Nagai, Yasuki; Kawabata, Masako; Sato, Nozomi; Hashimoto, Kazuyuki; Saeki, Hideya; Motoishi, Shoji*
Journal of the Physical Society of Japan, 83(8), p.083201_1 - 083201_4, 2014/07
Nagai, Yasuki; Hashimoto, Kazuyuki
Nihon Butsuri Gakkai-Shi, 69(6), p.370 - 375, 2014/06
In Japan, about 0.9 million diagnostic procedures are carried out using Tc, the daughter nuclide of Mo with a half-life of 66 h, separated from Mo; all Mo radioisotopes are imported. Most of Mo has been produced by the fission reaction of highly enriched U in research reactors in the world. However, a number of incidents of the reactors caused the shortage of Mo worldwide, which triggered widespread discussions on the reliable supply of Mo. We proposed a new route to produce a large quantity of high quality Mo using fast neutrons from an accelerator.
Segawa, Mariko; Toh, Yosuke; Harada, Hideo; Kitatani, Fumito; Koizumi, Mitsuo; Fukahori, Tokio; Oshima, Masumi*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Hatsukawa, Yuichi; et al.
AIP Conference Proceedings 1594, p.339 - 344, 2014/05
Hashimoto, Kazuyuki; Nagai, Yasuki
Comprehensive Biomedical Physics, Vol.8, p.219 - 227, 2014/00
Radionuclides for medical use are produced in nuclear reactors and in accelerators. The thermal neutron fluxes in nuclear reactors are several orders of magnitude higher than those of other neutron sources, such as accelerator neutrons. Hence, nuclear reactors have been playing important roles in the production of large quantity of medical radionuclides with their half-lives longer than several days. In accelerators, medical radionuclides with their half-lives longer than several minutes are produced. Recent progresses in accelerator technology as well as targetry technology, however, could enable one to obtain high-flux bremsstrahlung and intense energetic accelerator neutrons, and thereby to study new routes to produce medical radionuclides.
Hoshasen, 39(2), P. 43, 2013/11
When I was carrying out a basic study of nucleus physics using an accelerator, I was impressed with the ability of the accelerator. I thought that accelerators could contribute innovative works in many industry fields. In the practical application of accelerators in the medicine and industry, one has to find an important and interesting subject to be worth challenge on the basis of one's own knowledge and experience. Here, I would like to report my experience of the medicine and industrial use of accelerators.
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
Kin, Tadahiro*; Nagai, Yasuki; Iwamoto, Nobuyuki; Minato, Futoshi; Iwamoto, Osamu; Hatsukawa, Yuichi; Segawa, Mariko; Harada, Hideo; Konno, Chikara; Ochiai, Kentaro; et al.
Journal of the Physical Society of Japan, 82(3), p.034201_1 - 034201_8, 2013/03
We have measured the activation cross sections producing Cu and Cu, promising medical radioisotopes for molecular imaging and radioimmunotherapy, by bombarding a natural zinc sample with 14 MeV neutrons. We estimated the production yields of Cu and Cu by fast neutrons from C(d,n) with 40 MeV 5 mA deuterons. The calculated Cu yield is 1.8 TBq (175 g Zn) for 12 h of irradiation; the yields of Cu by Zn(n,p)Cu and Zn(n,x)Cu were 249 GBq (184 g Zn) and 287 GBq (186 g Zn) at the end of 2 days of irradiation, respectively. From the results, we proposed a new route to produce Cu with very little radionuclide impurity via the Zn(n,x)Cu reaction, and showed the Zn(n,p)Cu reaction to be a promising route to produce Cu.
Radioisotopes, 61(12), p.619 - 624, 2012/12
A new method was proposed to produce Mo by the Mo(n,2n)Mo reaction using intense neutrons from an accelerator by us. About 20% of the demand of Mo in Japan could be obtained constantly by the proposed method. In fact, we have shown that the produced Mo contained very little RI impurity and the radionuclide purity of Tc separated from Mo by sublimation and the labeling efficiency of Tc-MDP exceed the United States Pharmacopeia requirements for a fission product, Mo. We expect that the present Mo production method will be accepted worldwide to ensure the constant domestic supply of Mo.