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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
Times Cited Count:0 Percentile:35.17(Physics, Multidisciplinary)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
Times Cited Count:4 Percentile:62.43(Chemistry, Analytical)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
Times Cited Count:3 Percentile:48.33(Physics, Nuclear)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
Times Cited Count:2 Percentile:23.91(Physics, Multidisciplinary)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
Times Cited Count:9 Percentile:58.67(Physics, Multidisciplinary)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
Times Cited Count:8 Percentile:54.81(Physics, Multidisciplinary)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
Times Cited Count:13 Percentile:67.32(Physics, Multidisciplinary)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
Times Cited Count:7 Percentile:50.14(Physics, Multidisciplinary)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
Times Cited Count:2 Percentile:18.05(Chemistry, Analytical)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
Times Cited Count:6 Percentile:45.89(Physics, Multidisciplinary)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
Times Cited Count:13 Percentile:64.64(Physics, Multidisciplinary)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
Times Cited Count:10 Percentile:58.38(Physics, Multidisciplinary)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
Times Cited Count:0 Percentile:0.02Hashimoto, 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.
Nagai, Yasuki
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
Times Cited Count:41 Percentile:85.04(Physics, Multidisciplinary)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
Times Cited Count:33 Percentile:81.47(Physics, Multidisciplinary)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.
Nagai, Yasuki
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.