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Journal Articles

Extraction of $$^{99}$$Mo hot atoms made by a neutron capture method from $$alpha$$-MoO$$_{3}$$ to water

Quach, N. M.*; Ngo, M. C.*; Yang, Y.*; Nguyen, T. B.*; Nguyen, V. T.*; Fujita, Yoshitaka; Do, T. M. D.*; Nakayama, Tadachika*; Suzuki, Tatsuya*; Suematsu, Hisayuki*

Journal of Radioanalytical and Nuclear Chemistry, 332(10), p.4057 - 4064, 2023/10

https://doi.org/10.1007/s10967-023-09125-7
 Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)

Technetium-99m ($$^{99m}$$Tc) is the most widely used medical radioisotope in the world and is produced from molybdenum-99 ($$^{99}$$Mo). Production of $$^{99}$$Mo via the neutron capture method draws attention as an alternative to fission-derived $$^{99}$$Mo due to non-proliferation issues, but the specific radioactivity of $$^{99}$$Mo is extremely low. In this work, a porous $$alpha$$-MoO$$_{3}$$ wire was prepared as an irradiation target in order to improve the specific activity by extracting $$^{99}$$Mo. Porous $$alpha$$-MoO$$_{3}$$ wire is synthesized from Mo metal wire by a two-step heating procedure. The hot atom effect of $$^{99}$$Mo was confirmed by activity and isotope measurements of the porous $$alpha$$-MoO$$_{3}$$ wire after neutron irradiation and the water used for extraction. In term of the extraction effectiveness, the effectiveness of $$^{99}$$Mo extraction in the porous $$alpha$$-MoO$$_{3}$$ wire was comparable to that of commercial $$alpha$$-MoO$$_{3}$$ powder.

Journal Articles

$$beta$$-MoO$$_{3}$$ whiskers in $$^{99}$$Mo/$$^{rm 99m}$$Tc radioisotope production and $$^{99}$$Mo/$$^{rm 99m}$$Tc extraction using hot atoms

Ngo, M. C.*; Fujita, Yoshitaka; Suzuki, Tatsuya*; Do, T. M. D.*; Seki, Misaki; Nakayama, Tadachika*; Niihara, Koichi*; Suematsu, Hisayuki*

Inorganic Chemistry, 62(32), p.13140 - 13147, 2023/08

https://doi.org/10.1021/acs.inorgchem.3c02125
 Times Cited Count：0 Percentile：0.01(Chemistry, Inorganic & Nuclear)

Technetium-99m ($$^{rm 99m}$$Tc) is one of the most important radioisotopes for diagnostic radio-imaging applications. $$^{rm 99m}$$Tc is a daughter product of the $$^{99}$$Mo isotope. There are two methods used to produce $$^{99}$$Mo/$$^{rm 99m}$$Tc: the nuclear fission (n,f) and the neutron capture (n,$$gamma$$) methods. Between them, the (n,f) method is the main route, used for approximately 90% of the world's production. However, the (n,f) method faces numerous problems, including the use of highly enriched uranium, the release of highly radioactive waste, and nonproliferation problems. Therefore, the (n,$$gamma$$) method is being developed as a future replacement for the (n,f) method. In this work, $$beta$$-MoO$$_{3}$$ whiskers prepared by the thermal evaporation method and $$alpha$$-MoO$$_{3}$$ particles were irradiated in a nuclear reactor to produce $$^{99}$$Mo/$$^{rm 99m}$$Tc via neutron capture. The irradiated targets were dispersed into water to extract the $$^{99}$$Mo/$$^{rm 99m}$$Tc. As a result, $$beta$$-MoO$$_{3}$$ whisker yielded higher $$^{99}$$Mo extraction rate than that from $$alpha$$-MoO$$_{3}$$. In addition, by comparing the dissolved $$^{98}$$Mo concentrations in water, we clarified a prominent hot-atom of $$beta$$-MoO$$_{3}$$ whiskers. This research is the first demonstration of $$beta$$-MoO$$_{3}$$ being used as an irradiation target in the neutron capture method. On the basis of the results, $$beta$$-MoO$$_{3}$$ is considered a promising irradiation target for producing $$^{99}$$Mo/$$^{rm 99m}$$Tc by neutron capture and using water for the radioisotope extraction process in the future.

Journal Articles

Study on $$^{rm 99m}$$Tc separation/concentration technology from $$^{99}$$Mo by (n, $$gamma$$) method

Fujita, Yoshitaka; Hu, X.*; Takeuchi, Tomoaki; Takeda, Ryoma; Fujihara, Yasuyuki*; Yoshinaga, Hisao*; Hori, Junichi*; Suzuki, Tatsuya*; Suematsu, Hisayuki*; Ide, Hiroshi

KURNS Progress Report 2022, P. 110, 2023/07

https://www.rri.kyoto-u.ac.jp/PUB/report/PR/ProgRep2022/ProgressReport2022.pdf#page=125

no abstracts in English

Journal Articles

Radiochemical research for the advancement of $$^{99}$$Mo/$$^{rm 99m}$$Tc generator by (n, $$gamma$$) method, 4

Fujita, Yoshitaka; Seki, Misaki; Ngo, M. C.*; Do, T. M. D.*; Hu, X.*; Yang, Y.*; Takeuchi, Tomoaki; Nakano, Hiroko; Fujihara, Yasuyuki*; Yoshinaga, Hisao*; et al.

KURNS Progress Report 2021, P. 118, 2022/07

https://www.rri.kyoto-u.ac.jp/PUB/report/PR/ProgRep2021/ProgressReport2021_online.pdf#page=134

no abstracts in English

Journal Articles

Mechanisms responsible for adsorption of molybdate ions on alumina for the production of medical radioisotopes

Fujita, Yoshitaka; Niizeki, Tomotake*; Fukumitsu, Nobuyoshi*; Ariga, Katsuhiko*; Yamauchi, Yusuke*; Malgras, V.*; Kaneti, Y. V.*; Liu, C.-H.*; Hatano, Kentaro*; Suematsu, Hisayuki*; et al.

Bulletin of the Chemical Society of Japan, 95(1), p.129 - 137, 2022/01

https://doi.org/10.1246/bcsj.20210249
 Times Cited Count：8 Percentile：74.08(Chemistry, Multidisciplinary)

In this work, the mechanisms responsible for the adsorption of molybdate ions on alumina are investigated using in-depth surface analyses carried out on alumina specimens immersed in solutions containing different molybdate ions at different pH values. The obtained results reveal that when alumina is immersed in an acidic solution containing molybdate ions, the hydroxyl groups present on the surface are removed to generate positively charged sites, and molybdate ions (MoO$$_{4}$$$$^{2-}$$ or AlMo$$_{6}$$O$$_{24}$$H$$_{6}$$$$^{3-}$$) are adsorbed by electrostatic interaction. Alumina dissolves slightly in an acidic solution to form AlMo$$_{6}$$O$$_{24}$$H$$_{6}$$$$^{3-}$$, which is more easily desorbed than MoO$$_{4}$$$$^{2-}$$. Furthermore, the enhancement in the Mo adsorption or desorption property may be achieved by enriching the surface of the alumina adsorbent with many -OH groups and optimizing Mo solution to adsorb molybdate ions on alumina as MoO$$_{4}$$$$^{2-}$$ ions. These findings will assist researchers in engineering more efficient and stable alumina-based adsorbents for molybdenum adsorption used in medical radioisotope ($$^{99}$$Mo/$$^{99m}$$Tc) generators.

Journal Articles

Dynamic properties on $$^{99}$$Mo adsorption and $$^{rm 99m}$$Tc elution with alumina columns

Fujita, Yoshitaka; Seki, Misaki; Sano, Tadafumi*; Fujihara, Yasuyuki*; Suzuki, Tatsuya*; Yoshinaga, Hisao*; Hori, Junichi*; Suematsu, Hisayuki*; Tsuchiya, Kunihiko

Journal of Physics; Conference Series, 2155, p.012018_1 - 012018_6, 2022/01

https://doi.org/10.1088/1742-6596/2155/1/012018

Technetium-99m ($$^{rm 99m}$$Tc), the daughter nuclide of Molybdenum-99 ($$^{99}$$Mo), is the most commonly used radioisotope in radiopharmaceuticals. The research and development (R&D) for the production of $$^{99}$$Mo by the neutron activation method ((n, $$gamma$$) method) has been carried out from viewpoints of no-proliferation and nuclear security, etc. Since the specific activity of $$^{99}$$Mo produced by the (n, $$gamma$$) method is extremely low, developing Al$$_{2}$$O$$_{3}$$ with a large Mo adsorption capacity is necessary to adapt (n, $$gamma$$)$$^{99}$$Mo to the generator. In this study, three kinds of Al$$_{2}$$O$$_{3}$$ specimens with different raw materials were prepared and compared their adaptability to generators by static and dynamic adsorption. MoO$$_{3}$$ pellet pieces (1.5g) were irradiated with 5 MW for 20 min in the Kyoto University Research Reactor (KUR). Irradiated MoO$$_{3}$$ pellet pieces were dissolved in 6M-NaOH aq. In dynamic adsorption, 1 g of Al$$_{2}$$O$$_{3}$$ was filled into a PFA tube ($$phi$$1.59 mm). The $$^{99}$$Mo adsorption capacity of Al$$_{2}$$O$$_{3}$$ specimens under dynamic condition was slightly reduced compared to that under static condition. The $$^{rm 99m}$$Tc elution rate was about 100% at 1.5 mL of milking in dynamic adsorption, while it was around 56-87% in static adsorption. The $$^{99}$$Mo/$$^{rm 99m}$$Tc ratio of dynamic condition was greatly reduced compared to that of static condition. Therefore, the $$^{rm 99m}$$Tc elution property is greatly affected by the method of adsorbing Mo, e.g., the column shape, the linear flow rate, etc.

Journal Articles

Radiochemical research for the advancement of $$^{99}$$Mo/$$^{rm 99m}$$Tc generator by (n, $$gamma$$) method, 3

Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Daigo, Fumihisa; Ide, Hiroshi; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; Hori, Junichi*; et al.

KURNS Progress Report 2020, P. 136, 2021/08

no abstracts in English

Journal Articles

Two-step-pressurization method in pulsed electric current sintering of MoO$$_{3}$$ for production of $$^{99m}$$Tc radioactive isotope

Suematsu, Hisayuki*; Sato, Soma*; Nakayama, Tadachika*; Suzuki, Tatsuya*; Niihara, Koichi*; Nanko, Makoto*; Tsuchiya, Kunihiko

Journal of Asian Ceramic Societies (Internet), 8(4), p.1154 - 1161, 2020/12

https://doi.org/10.1080/21870764.2020.1824326
 Times Cited Count：3 Percentile：16.44(Materials Science, Ceramics)

Pulsed electric current sintering of molybdenum trioxide (MoO$$_{3}$$) was carried out by one- and two-step pressuring methods for fabrication of irradiation target using production of $$^{99}$$Mo and $$^{rm 99m}$$Tc nuclear medicine. At 550$$^{circ}$$C by the two-step pressurizing method, a relative density of 93.1% was obtained while, by the one-step pressurization method, the relative density was 76.9%. Direct sample temperature measurements were conducted by inserting a thermocouple in a punch. By the two-step pressurizing method, the sample temperature was higher than that by the one-step pressurizing method even almost the same die temperature. From voltage and current waveforms, it was thought that the conductivity of the sample increased by the two-step pressurizing method to increase the sample temperature and the relative density. The two-step pressurization method enables us to prepare dense targets at a low temperature from recycled and coarse-grained $$^{98}$$Mo enriched MoO$$_{3}$$ powder.

Journal Articles

Radiochemical research for the advancement of $$^{99}$$Mo/$$^{rm 99m}$$Tc generator by (n,$$gamma$$) method, 2

Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Kato, Yoshiaki; Sayato, Natsuki; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; Hori, Junichi*; et al.

KURNS Progress Report 2019, P. 157, 2020/08

https://www.rri.kyoto-u.ac.jp/PUB/report/PR/ProgRep2019/ProgressReport2019_online.pdf#page=173

no abstracts in English

Journal Articles

Radiochemical research for the advancement of $$^{99}$$Mo/$$^{rm 99m}$$Tc generator by (n,$$gamma$$) method

Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Kimura, Akihiro; Shibata, Akira; Sayato, Natsuki; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.

KURNS Progress Report 2018, P. 155, 2019/08

https://www.rri.kyoto-u.ac.jp/PUB/report/PR/ProgRep2018/KURNS_Progress_Report2018_web.pdf

no abstracts in English

Journal Articles

Radiation resistance of optical fibers, VI

Kakuta, Tsunemi; Ara, Katsuyuki; ; *; *; *; *; *

EIM-87-128, p.45 - 51, 1987/00

no abstracts in English

Journal Articles

Radiation resistance of fiber optics (III)

; ; *; *; *; *; *

EIM-85-30, p.37 - 43, 1985/04

no abstracts in English

Journal Articles

Radiation resistane of fiber optics, IV;

; ; *; *; *; *; *

EIM-85-131, p.1 - 27, 1985/00

no abstracts in English

Journal Articles

Radiation effects in pure silica core and ge-doped silica core fibers

; ; *; *; *; *; *; *

Fujikura Densen Giho, 66, p.42 - 50, 1983/00

no abstracts in English

Oral presentation

Nuclide separation by water for development of $$^{99}$$Mo/$$^{99m}$$Tc generator for medical

Seki, Misaki*; Suematsu, Hisayuki*; Nakayama, Tadachika*; Suzuki, Tsuneo*; Niihara, Koichi*; Suzuki, Tatsuya*; Tsuchiya, Kunihiko; Duong Van, D.*

no journal, , 

no abstracts in English

Oral presentation

Pulsed electric current sintering of MoO$$_{3}$$ and the neutron irradiation tests

Suematsu, Hisayuki*; Seki, Misaki; Nakayama, Tadachika*; Nishikata, Kaori; Nanko, Makoto*; Suzuki, Tatsuya*; Tsuchiya, Kunihiko

no journal, , 

Pulsed electric current sintering (PECS) of MoO$$_{3}$$ was carried out for a high density target to produce $$^{99m}$$Tc from $$^{98}$$Mo in a nuclear reactor. The green compacts of MoO$$_{3}$$ were heated in a PECS apparatus with a heating rate of 100 $$^{circ}$$C/min to 450 - 550 $$^{circ}$$C in vacuum and changing the pressurization profile from 0 to 40 MPa. After two step pressurization for sintering at 550 $$^{circ}$$C, the sintered MoO$$_{3}$$ bulk had a relative density of 94%, which was higher than that of one step pressurization. Direct temperature measurements near the sample were carried out. The results indicated that the sample temperature was higher for the two step than for the one step pressurization even in the same die temperature experiments. By the low pressure in two step pressurization, it was thought that open pores remained in the sintered body to reduce MoO$$_{3}$$ in vacuum. This oxygen depleted MoO$$_{3-x}$$ grains showed low electrical resistivity and formed a current path in the sintered body to increase the temperature to increase the relative density.

Oral presentation

Effect of column shape on $$^{99}$$Mo adsorption/$$^{99m}$$Tc elution property

Fujita, Yoshitaka; Seki, Misaki; Fujihara, Yasuyuki*; Suzuki, Tatsuya*; Yoshinaga, Hisao*; Takeuchi, Tomoaki; Nakano, Hiroko; Hori, Junichi*; Suematsu, Hisayuki*; Ide, Hiroshi

no journal, , 

no abstracts in English

Oral presentation

Isotope production using novel MoO$$_{3}$$ targets; Contribution by vietnamese institutes, staffs and students

Suematsu, Hisayuki*; Ngo, M. C.*; Quach, N. M.*; Fujita, Yoshitaka; Do, T. M. D.*; Nakayama, Tadachika*; Suzuki, Tatsuya*; Nguyen, V. T.*; Niihara, Koichi*

no journal, , 

Radiopharmacies have been used in various medical diagnoses/therapies and their market has been growing by ten times in fifteen years. In particular, $$^{99m}$$Tc has been widely used in gamma ray diagnoses. $$^{99}$$Mo, the raw material for $$^{99m}$$Tc, is currently produced as a fission product by irradiating highly enriched uranium in nuclear reactors. Efforts are being made worldwide to reduce the use of uranium from the perspective of nuclear non-proliferation. A $$^{98}$$Mo(n,$$gamma$$)$$^{99}$$Mo reaction in low enriched uranium reactors can be an alternative method. In this research, we revealed that $$beta$$-MoO$$_{3}$$, a low-temperature phase of MoO$$_{3}$$, as a neutron irradiation target promotes the diffusion of $$^{99}$$Mo from the target to water due to the hot atom effect. Utilizing this phenomenon can contribute to the stable supply of $$^{99}$$Mo and $$^{99m}$$Tc. The first nuclear reaction in/water dispersion experiments using an $$alpha$$-MoO$$_{3}$$ powder target was carried out in Dalat Nuclear Reactor, Vietnam Atomic Energy Institute to show the hot atom effect. Then, the water recovery efficiency was dramatically improved using a novel $$beta$$-MoO$$_{3}$$ whisker target by Vietnamese students and staffs. Their contributions to this research will be explained in the presentation.

Patent

モリブデン-99の製造用ターゲット材料及びその製造方法

藤田 善貴

末松 久幸*; 中山 忠親*; Do Thi Mai Dung*; 鈴木 達也*; Ngo Minh Chu*

JP, 2022-63746  Patent licensing information

【課題】水に分散させた中性子照射したターゲットに関し、フィルターで濾過可能で、溶液中に高濃度のMO-99を抽出する方法が求められていることに着目し、形状制御したターゲット材料を開発すること。 【解決手段】長径と短径が大きく異なる細長いMOO3ウイスカー材料をターゲットとし、中性子照射後水に分散させ、フィルターで溶液と分離してMO-99を高い濃度で溶液に抽出する。

19 (Records 1-19 displayed on this page)
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