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Masahiro Hosoda
Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Honcho, Hirosaki, Aomori 036-8564, Japan

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Journal article
Published: 28 July 2021 in Atmosphere
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Recently, some commercially available active-type radon–thoron monitors were developed; however, their performance has not been characterized. This article presents the characteristics of three commercially available active-type radon–thoron monitors (RAD7, Radon Mapper, and AlphaGUARD) at different sampling flow rates. The thoron concentration measured by the monitors was compared with the reference value measured by a grab sampling method. As a result, the ratio of the measured concentration to the reference increased with flow rate for the RAD7 and the Radon Mapper although that of the AlphaGUARD decreased. The difference may be attributed to the coefficients used in the calculation and the measurement time scheme. The results indicate the importance of the sampling flow rate in thoron measurement. Monitoring of flow rate at the measurement and periodic calibration at multiple sampling flow rates should be conducted for quality assurance and quality control of the measurand.

ACS Style

Yuki Tamakuma; Chutima Kranrod; Yuto Jin; Hiromu Kobayashi; Eka Nugraha; Aoi Sanpei; Mizuki Kiso; Hiroki Hashimoto; Ryoju Negami; Masahiro Hosoda; Shinji Tokonami. Characterization of Commercially Available Active-Type Radon–Thoron Monitors at Different Sampling Flow Rates. Atmosphere 2021, 12, 971 .

AMA Style

Yuki Tamakuma, Chutima Kranrod, Yuto Jin, Hiromu Kobayashi, Eka Nugraha, Aoi Sanpei, Mizuki Kiso, Hiroki Hashimoto, Ryoju Negami, Masahiro Hosoda, Shinji Tokonami. Characterization of Commercially Available Active-Type Radon–Thoron Monitors at Different Sampling Flow Rates. Atmosphere. 2021; 12 (8):971.

Chicago/Turabian Style

Yuki Tamakuma; Chutima Kranrod; Yuto Jin; Hiromu Kobayashi; Eka Nugraha; Aoi Sanpei; Mizuki Kiso; Hiroki Hashimoto; Ryoju Negami; Masahiro Hosoda; Shinji Tokonami. 2021. "Characterization of Commercially Available Active-Type Radon–Thoron Monitors at Different Sampling Flow Rates." Atmosphere 12, no. 8: 971.

Journal article
Published: 13 May 2021 in Applied Sciences
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Radiation dose management of medical staff has become increasingly important. Particularly, based on the statement by the International Commission on Radiological Protection (ICRP) in 2011, a new lower equivalent dose limit for the eye lens is being established in each country. Although many reports have discussed the occupational radiation dose in interventional radiology (IR), few studies have examined the dose during computed tomography (CT) examinations. This study investigated the radiation dose exposure to medical staff present in the CT room during irradiation, with particular focus on the exposure to eye lens. The radiation dose exposure to those who assist patients during head, chest and upper abdomen CT examination was measured in a phantom study. The radiation dose exposure with scattered radiation was never negligible (i.e., high); H p(3) was the highest in head CT examination, at 0.44 mSv per examination. Furthermore, the shielding effect of radiation protection glasses was large, and radiation protection glasses are useful tools for the medical staff who are involved in CT examinations. The justification and optimisation should be carefully considered in assistant actions.

ACS Style

Minoru Osanai; Hidenori Sato; Kana Sato; Kohsei Kudo; Masahiro Hosoda; Shota Hosokawa; Maiko Kitajima; Megumi Tsushima; Akira Fujita; Yoichiro Hosokawa; Yoko Saito. Occupational Radiation Dose, Especially for Eye Lens: Hp(3), in Medical Staff Members Involved in Computed Tomography Examinations. Applied Sciences 2021, 11, 4448 .

AMA Style

Minoru Osanai, Hidenori Sato, Kana Sato, Kohsei Kudo, Masahiro Hosoda, Shota Hosokawa, Maiko Kitajima, Megumi Tsushima, Akira Fujita, Yoichiro Hosokawa, Yoko Saito. Occupational Radiation Dose, Especially for Eye Lens: Hp(3), in Medical Staff Members Involved in Computed Tomography Examinations. Applied Sciences. 2021; 11 (10):4448.

Chicago/Turabian Style

Minoru Osanai; Hidenori Sato; Kana Sato; Kohsei Kudo; Masahiro Hosoda; Shota Hosokawa; Maiko Kitajima; Megumi Tsushima; Akira Fujita; Yoichiro Hosokawa; Yoko Saito. 2021. "Occupational Radiation Dose, Especially for Eye Lens: Hp(3), in Medical Staff Members Involved in Computed Tomography Examinations." Applied Sciences 11, no. 10: 4448.

Journal article
Published: 24 March 2021 in Foods
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This study examined the effect of food regulations under the current criteria (e.g., 100 Bq/kg for general foods) established approximately a year after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Foods are monitored to ensure that foods exceeding the standard limit are not distributed; ~300,000 examinations per year have been performed especially since FY2014. This study comprehensively estimated the internal exposure dose resulting from the ingestion of foods containing radioactive cesium using the accumulated monitoring results. Committed effective dose was conservatively calculated as the product of the radioactive concentration randomly sampled from test results, food intake, and dose coefficient. The median, 95th, and 99th percentile of the dose were 0.0479, 0.207, and 10.6 mSv/y, respectively, in the estimation with all test results (without regulation), and 0.0430, 0.0790, and 0.233 mSv/y, respectively, in the estimation with results within the standard limits (with regulation) in FY2012. In FY2016, the dose with and without regulation were similar, except for high percentile, and those doses were significantly smaller than 1 mSv/y, which was adopted as the basis for the current criteria. The food regulation measures implemented in Japan after the FDNPP accident have been beneficial, and food safety against radionuclides has been ensured.

ACS Style

Minoru Osanai; Daisuke Hirano; Shiori Mitsuhashi; Kohsei Kudo; Shota Hosokawa; Megumi Tsushima; Kazuki Iwaoka; Ichiro Yamaguchi; Takakiyo Tsujiguchi; Masahiro Hosoda; Yoichiro Hosokawa; Yoko Saito. Estimation of Effect of Radiation Dose Reduction for Internal Exposure by Food Regulations under the Current Criteria for Radionuclides in Foodstuff in Japan Using Monitoring Results. Foods 2021, 10, 691 .

AMA Style

Minoru Osanai, Daisuke Hirano, Shiori Mitsuhashi, Kohsei Kudo, Shota Hosokawa, Megumi Tsushima, Kazuki Iwaoka, Ichiro Yamaguchi, Takakiyo Tsujiguchi, Masahiro Hosoda, Yoichiro Hosokawa, Yoko Saito. Estimation of Effect of Radiation Dose Reduction for Internal Exposure by Food Regulations under the Current Criteria for Radionuclides in Foodstuff in Japan Using Monitoring Results. Foods. 2021; 10 (4):691.

Chicago/Turabian Style

Minoru Osanai; Daisuke Hirano; Shiori Mitsuhashi; Kohsei Kudo; Shota Hosokawa; Megumi Tsushima; Kazuki Iwaoka; Ichiro Yamaguchi; Takakiyo Tsujiguchi; Masahiro Hosoda; Yoichiro Hosokawa; Yoko Saito. 2021. "Estimation of Effect of Radiation Dose Reduction for Internal Exposure by Food Regulations under the Current Criteria for Radionuclides in Foodstuff in Japan Using Monitoring Results." Foods 10, no. 4: 691.

Journal article
Published: 04 February 2021 in International Journal of Environmental Research and Public Health
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A long-term measurement technique of radon exhalation rate was previously developed using a passive type radon and thoron discriminative monitor and a ventilated type accumulation chamber. In the present study, this technique was applied to evaluate the thoron exhalation rate as well, and long-term measurements of radon and thoron exhalation rates were conducted for four years in Gifu Prefecture. The ventilated type accumulation chamber (0.8 × 0.8 × 1.0 m3) with an open bottom was embedded 15 cm into the ground. The vertical distributions of radon and thoron activity concentrations from the ground were obtained using passive type radon-thoron discriminative monitors (RADUETs). The RADUETs were placed at 1, 3, 10, 30, and 80 cm above the ground inside the accumulation chamber. The measurements were conducted from autumn 2014 to autumn 2018. These long-term results were found to be in good agreement with the values obtained by another methodology. The radon exhalation rates from the ground showed a clearly seasonal variation. Similar to findings of previous studies, radon exhalation rates from summer to autumn were relatively higher than those from winter to spring. In contrast, thoron exhalation rates were not found to show seasonal variation.

ACS Style

Oumar Modibo; Yuki Tamakuma; Takahito Suzuki; Ryohei Yamada; Weihai Zhuo; Chutima Kranrod; Kazuki Iwaoka; Naofumi Akata; Masahiro Hosoda; Shinji Tokonami. Long-Term Measurements of Radon and Thoron Exhalation Rates from the Ground Using the Vertical Distributions of Their Activity Concentrations. International Journal of Environmental Research and Public Health 2021, 18, 1489 .

AMA Style

Oumar Modibo, Yuki Tamakuma, Takahito Suzuki, Ryohei Yamada, Weihai Zhuo, Chutima Kranrod, Kazuki Iwaoka, Naofumi Akata, Masahiro Hosoda, Shinji Tokonami. Long-Term Measurements of Radon and Thoron Exhalation Rates from the Ground Using the Vertical Distributions of Their Activity Concentrations. International Journal of Environmental Research and Public Health. 2021; 18 (4):1489.

Chicago/Turabian Style

Oumar Modibo; Yuki Tamakuma; Takahito Suzuki; Ryohei Yamada; Weihai Zhuo; Chutima Kranrod; Kazuki Iwaoka; Naofumi Akata; Masahiro Hosoda; Shinji Tokonami. 2021. "Long-Term Measurements of Radon and Thoron Exhalation Rates from the Ground Using the Vertical Distributions of Their Activity Concentrations." International Journal of Environmental Research and Public Health 18, no. 4: 1489.

Journal article
Published: 23 January 2021 in International Journal of Environmental Research and Public Health
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In this study, to get a better understanding in characterizing groundwater and ensure its effective management, the radon concentrations in water samples were measured through Ryukyu limestone in southern Okinawa Island, Japan. Water samples were collected from a limestone cave (Gyokusendo cave, dropping water) and two springs (Ukinju and Komesu, spring water), and the radon concentrations were measured by liquid scintillation counters. The radon concentrations in the samples from the Gyokusendo cave, and Ukinju and Komesu springs were 10 ± 1.3 Bq L−1, 3.2 ± 1.0 Bq L−1, and 3.1 ± 1.1 Bq L−1, respectively. The radon concentrations showed a gradually increasing trend from summer to autumn and decreased during winter. The variation of radon concentrations in the dripping water sample from the Gyokusendo cave showed a lagged response to precipitation changes by approximately 2–3 months. The estimated radon concentrations in the dripping water sample were calculated with the measured radon concentrations from the dripping water obtained during the study period. Based on our results, groundwater in the Gyokusendo cave system was estimated to percolate through the Ryukyu limestone in 7–10 days, and the residence time of groundwater in the soil above Gyokusendo cave was estimated to be approximately 50–80 days. This work makes a valuable contribution to the understanding of groundwater processes in limestone aquifers, which is essential for ensuring groundwater sustainability.

ACS Style

Shunya Nakasone; Akinobu Ishimine; Shuhei Shiroma; Natsumi Masuda; Kaori Nakamura; Yoshitaka Shiroma; Sohei Ooka; Masahiro Tanaka; Akemi Kato; Masahiro Hosoda; Naofumi Akata; Yumi Yasuoka; Masahide Furukawa. Temporal and Spatial Variation of Radon Concentrations in Environmental Water from Okinawa Island, Southwestern Part of Japan. International Journal of Environmental Research and Public Health 2021, 18, 998 .

AMA Style

Shunya Nakasone, Akinobu Ishimine, Shuhei Shiroma, Natsumi Masuda, Kaori Nakamura, Yoshitaka Shiroma, Sohei Ooka, Masahiro Tanaka, Akemi Kato, Masahiro Hosoda, Naofumi Akata, Yumi Yasuoka, Masahide Furukawa. Temporal and Spatial Variation of Radon Concentrations in Environmental Water from Okinawa Island, Southwestern Part of Japan. International Journal of Environmental Research and Public Health. 2021; 18 (3):998.

Chicago/Turabian Style

Shunya Nakasone; Akinobu Ishimine; Shuhei Shiroma; Natsumi Masuda; Kaori Nakamura; Yoshitaka Shiroma; Sohei Ooka; Masahiro Tanaka; Akemi Kato; Masahiro Hosoda; Naofumi Akata; Yumi Yasuoka; Masahide Furukawa. 2021. "Temporal and Spatial Variation of Radon Concentrations in Environmental Water from Okinawa Island, Southwestern Part of Japan." International Journal of Environmental Research and Public Health 18, no. 3: 998.

Journal article
Published: 22 January 2021 in International Journal of Environmental Research and Public Health
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Ten years have elapsed since the accident at the Fukushima Daiichi Nuclear Power Plant in 2011, and the relative contribution of natural radiation is increasing in Fukushima Prefecture due to the reduced dose of artificial radiation. In order to accurately determine the effective dose of exposure to artificial radiation, it is necessary to evaluate the effective dose of natural as well as artificial components. In this study, we measured the gamma-ray pulse-height distribution over the accessible area of Namie Town, Fukushima Prefecture, and evaluated the annual effective dose of external exposure by distinguishing between natural and artificial radionuclides. The estimated median (range) of absorbed dose rates in air from artificial radionuclides as of 1 April 2020, is 133 (67–511) nGy h−1 in the evacuation order cancellation zone, and 1306 (892–2081) nGy h−1 in the difficult-to-return zone. The median annual effective doses of external exposures from natural and artificial radionuclides were found to be 0.19 and 0.40 mSv in the evacuation order cancellation zone, and 0.25 and 3.9 mSv in the difficult-to-return zone. The latest annual effective dose of external exposure discriminated into natural and artificial radionuclides is expected to be utilized for radiation risk communication.

ACS Style

Koya Ogura; Masahiro Hosoda; Yuki Tamakuma; Takahito Suzuki; Ryohei Yamada; Ryoju Negami; Takakiyo Tsujiguchi; Masaru Yamaguchi; Yoshitaka Shiroma; Kazuki Iwaoka; Naofumi Akata; Mayumi Shimizu; Ikuo Kashiwakura; Shinji Tokonami. Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture. International Journal of Environmental Research and Public Health 2021, 18, 978 .

AMA Style

Koya Ogura, Masahiro Hosoda, Yuki Tamakuma, Takahito Suzuki, Ryohei Yamada, Ryoju Negami, Takakiyo Tsujiguchi, Masaru Yamaguchi, Yoshitaka Shiroma, Kazuki Iwaoka, Naofumi Akata, Mayumi Shimizu, Ikuo Kashiwakura, Shinji Tokonami. Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture. International Journal of Environmental Research and Public Health. 2021; 18 (3):978.

Chicago/Turabian Style

Koya Ogura; Masahiro Hosoda; Yuki Tamakuma; Takahito Suzuki; Ryohei Yamada; Ryoju Negami; Takakiyo Tsujiguchi; Masaru Yamaguchi; Yoshitaka Shiroma; Kazuki Iwaoka; Naofumi Akata; Mayumi Shimizu; Ikuo Kashiwakura; Shinji Tokonami. 2021. "Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture." International Journal of Environmental Research and Public Health 18, no. 3: 978.

Journal article
Published: 21 January 2021 in International Journal of Environmental Research and Public Health
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The world community has long used natural hot springs for tourist and medicinal purposes. In Indonesia, the province of West Java, which is naturally surrounded by volcanoes, is the main destination for hot spring tourism. This paper is the first report on radon measurements in tourism natural hot spring water in Indonesia as part of radiation protection for public health. The purpose of this paper is to study the contribution of radon doses from natural hot spring water and thereby facilitate radiation protection for public health. A total of 18 water samples were measured with an electrostatic collection type radon monitor (RAD7, Durridge Co., USA). The concentration of radon in natural hot spring water samples in the West Java region, Indonesia ranges from 0.26 to 31 Bq L−1. An estimate of the annual effective dose in the natural hot spring water area ranges from 0.51 to 0.71 mSv with a mean of 0.60 mSv for workers. Meanwhile, the annual effective dose for the public ranges from 0.10 to 0.14 mSv with an average of 0.12 mSv. This value is within the range of the average committed effective dose from inhalation and terrestrial radiation for the general public, 1.7 mSv annually.

ACS Style

Eka Nugraha; Masahiro Hosoda; June Mellawati; Untara Untara; Ilsa Rosianna; Yuki Tamakuma; Oumar Modibo; Chutima Kranrod; Kusdiana Kusdiana; Shinji Tokonami. Radon Activity Concentrations in Natural Hot Spring Water: Dose Assessment and Health Perspective. International Journal of Environmental Research and Public Health 2021, 18, 920 .

AMA Style

Eka Nugraha, Masahiro Hosoda, June Mellawati, Untara Untara, Ilsa Rosianna, Yuki Tamakuma, Oumar Modibo, Chutima Kranrod, Kusdiana Kusdiana, Shinji Tokonami. Radon Activity Concentrations in Natural Hot Spring Water: Dose Assessment and Health Perspective. International Journal of Environmental Research and Public Health. 2021; 18 (3):920.

Chicago/Turabian Style

Eka Nugraha; Masahiro Hosoda; June Mellawati; Untara Untara; Ilsa Rosianna; Yuki Tamakuma; Oumar Modibo; Chutima Kranrod; Kusdiana Kusdiana; Shinji Tokonami. 2021. "Radon Activity Concentrations in Natural Hot Spring Water: Dose Assessment and Health Perspective." International Journal of Environmental Research and Public Health 18, no. 3: 920.

Journal article
Published: 18 November 2020 in International Journal of Environmental Research and Public Health
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An improved passive CR-39-based direct 222Rn/220Rn progeny detector with 3 detection channels was designed and tested in this study to measure and calculate equilibrium equivalent concentration (EEC) of both 222Rn and 220Rn without the equilibrium factor. A theoretical model was established to calculate the EEC with optimization. Subsequently, an exposure experiment was carried out to test the performance of this detector, and we compared the chamber experiment and the theoretical model by estimating and measuring various parameters. The deposition flux of progeny derived from the prediction agreed well with the value measured in the exposure chamber. The energy-weighted net track density (NTD) measured by this detector is much more reliable to reflect the linear relation between NTD and time-integrated EEC. Since the detector is sensitive to the exposure environmental condition, it is recommended to apply the detector to measure the EEC after its calibration in a typical indoor environment.

ACS Style

Jun Hu; Guosheng Yang; Chutima Kranrod; Kazuki Iwaoka; Masahiro Hosoda; Shinji Tokonami. An Improved Passive CR-39-Based Direct 222Rn/220Rn Progeny Detector. International Journal of Environmental Research and Public Health 2020, 17, 1 .

AMA Style

Jun Hu, Guosheng Yang, Chutima Kranrod, Kazuki Iwaoka, Masahiro Hosoda, Shinji Tokonami. An Improved Passive CR-39-Based Direct 222Rn/220Rn Progeny Detector. International Journal of Environmental Research and Public Health. 2020; 17 (22):1.

Chicago/Turabian Style

Jun Hu; Guosheng Yang; Chutima Kranrod; Kazuki Iwaoka; Masahiro Hosoda; Shinji Tokonami. 2020. "An Improved Passive CR-39-Based Direct 222Rn/220Rn Progeny Detector." International Journal of Environmental Research and Public Health 17, no. 22: 1.

Journal article
Published: 19 September 2020 in Geosciences
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Mamuju is a region of Indonesia with relatively high exposure to natural radiation. Since 2012, Mamuju has been a uranium and thorium exploration area. Several mapping studies of the region have been carried out to depict NORM (naturally occurring radioactive material) areas and areas with uranium anomalies. This paper is the first study to use radioactivity measurements of laterite and volcanic rocks to determine the characteristics of radionuclides and other mineral measurements, which are essential for categorising Mamuju rocks and exploring the region as a potential mining area. The radioactivity of the samples was measured using a high-purity germanium (HPGe) detector. Furthermore, we used X-ray fluorescence (XRF) to determine the rock mineral composition. Mamuju is anomalous due to its high content of 238U and 232Th concentrations of 539–128,699 Bq·kg−1 (average: 22,882 Bq·kg−1) and 471–288,639 Bq·kg−1 (average: 33,549 Bq·kg−1), respectively. The major elements are dominant, including Fe2O3, SiO2, Al2O3, and Na2O, with several other major elements such as MnO, TiO2, and CaO.

ACS Style

Ilsa Rosianna; Eka Nugraha; Heri Syaeful; Sugili Putra; Masahiro Hosoda; Naofumi Akata; Shinji Tokonami. Natural Radioactivity of Laterite and Volcanic Rock Sample for Radioactive Mineral Exploration in Mamuju, Indonesia. Geosciences 2020, 10, 376 .

AMA Style

Ilsa Rosianna, Eka Nugraha, Heri Syaeful, Sugili Putra, Masahiro Hosoda, Naofumi Akata, Shinji Tokonami. Natural Radioactivity of Laterite and Volcanic Rock Sample for Radioactive Mineral Exploration in Mamuju, Indonesia. Geosciences. 2020; 10 (9):376.

Chicago/Turabian Style

Ilsa Rosianna; Eka Nugraha; Heri Syaeful; Sugili Putra; Masahiro Hosoda; Naofumi Akata; Shinji Tokonami. 2020. "Natural Radioactivity of Laterite and Volcanic Rock Sample for Radioactive Mineral Exploration in Mamuju, Indonesia." Geosciences 10, no. 9: 376.

Journal article
Published: 05 August 2020 in International Journal of Environmental Research and Public Health
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The International Commission on Radiological Protection (ICRP) recently recommended a new dose conversion factor for radon based on the latest epidemiological studies and dosimetric model. It is important to evaluate an inhalation dose from radon and its progeny. In the present study, a passive radon personal monitor was designed using a small container for storing contact lenses and its performance was evaluated. The conversion factor for radon (222Rn), the effect of thoron (220Rn) concentration and the air exchange rate were evaluated using the calibration chamber at Hirosaki University. The minimum and maximum detectable radon concentrations were calculated. The conversion factor was evaluated as 2.0 ± 0.3 tracks cm−2 per kBq h m−3; statistical analyses of results showed no significant effect from thoron concentration. The minimum and maximum detectable radon concentrations were 92 Bq m−3 and 231 kBq m−3 for a measurement period of three months, respectively. The air exchange rate was estimated to be 0.26 ± 0.16 h−1, whose effect on the measured time-integrated radon concentration was small. These results indicate that the monitor could be used as a wearable monitor for radon measurements, especially in places where radon concentrations may be relatively high, such as mines and caves.

ACS Style

Yuki Tamakuma; Chutima Kranrod; Takahito Suzuki; Yuki Watanabe; Thamaborn Ploykrathok; Ryoju Negami; Eka Djatnika Nugraha; Kazuki Iwaoka; Mirosław Janik; Masahiro Hosoda; Shinji Tokonami. Passive-Type Radon Monitor Constructed Using a Small Container for Personal Dosimetry. International Journal of Environmental Research and Public Health 2020, 17, 5660 .

AMA Style

Yuki Tamakuma, Chutima Kranrod, Takahito Suzuki, Yuki Watanabe, Thamaborn Ploykrathok, Ryoju Negami, Eka Djatnika Nugraha, Kazuki Iwaoka, Mirosław Janik, Masahiro Hosoda, Shinji Tokonami. Passive-Type Radon Monitor Constructed Using a Small Container for Personal Dosimetry. International Journal of Environmental Research and Public Health. 2020; 17 (16):5660.

Chicago/Turabian Style

Yuki Tamakuma; Chutima Kranrod; Takahito Suzuki; Yuki Watanabe; Thamaborn Ploykrathok; Ryoju Negami; Eka Djatnika Nugraha; Kazuki Iwaoka; Mirosław Janik; Masahiro Hosoda; Shinji Tokonami. 2020. "Passive-Type Radon Monitor Constructed Using a Small Container for Personal Dosimetry." International Journal of Environmental Research and Public Health 17, no. 16: 5660.

Journal article
Published: 11 July 2020 in International Journal of Environmental Research and Public Health
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Activity concentrations of 234U, 235U, 238U, 226Ra, 228Ra, 222Rn, 210Po, 210Pb, 40K, 3H, 14C, 134Cs and 137Cs were determined in 20 different Japanese bottled drinking water commercially available in Japan. The origins of the mineral water samples were geographically distributed across different regions of Japan. Activity concentrations above detection limits were measured for the radionuclides 234U, 235U, 238U, 226Ra, 228Ra and 210Po. An average total annual effective dose due to ingestion was estimated for adults, based on the average annual volume of bottled water consumed in Japan in 2019, reported to be 31.7 L/y per capita. The estimated dose was found to be below the recommended World Health Organisation (WHO) guidance level of 0.1 mSv/y for drinking water quality. The most significant contributor to the estimated dose was 228Ra.

ACS Style

Aoife Kinahan; Masahiro Hosoda; Kevin Kelleher; Takakiyo Tsujiguchi; Naofumi Akata; Shinji Tokonami; Lorraine Currivan; Luis Leon Vintro. Assessment of Radiation Dose from the Consumption of Bottled Drinking Water in Japan. International Journal of Environmental Research and Public Health 2020, 17, 4992 .

AMA Style

Aoife Kinahan, Masahiro Hosoda, Kevin Kelleher, Takakiyo Tsujiguchi, Naofumi Akata, Shinji Tokonami, Lorraine Currivan, Luis Leon Vintro. Assessment of Radiation Dose from the Consumption of Bottled Drinking Water in Japan. International Journal of Environmental Research and Public Health. 2020; 17 (14):4992.

Chicago/Turabian Style

Aoife Kinahan; Masahiro Hosoda; Kevin Kelleher; Takakiyo Tsujiguchi; Naofumi Akata; Shinji Tokonami; Lorraine Currivan; Luis Leon Vintro. 2020. "Assessment of Radiation Dose from the Consumption of Bottled Drinking Water in Japan." International Journal of Environmental Research and Public Health 17, no. 14: 4992.

Review
Published: 10 June 2020 in International Journal of Environmental Research and Public Health
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Radon (222Rn) and thoron (220Rn), sources of natural background radiation, have been the subjects of long-standing studies, including research into radon and thoron as major causes of lung cancer at domestic and international levels. In this regard, radon and thoron measurement studies have been widely conducted all over the world. Generally, the techniques used relate to passive nuclear track detectors. Some surveys have shown that passive monitors for radon are sensitive to thoron, and hence some measured results have probably overestimated radon concentrations. This study investigated radon and thoron measurements in domestic and international surveys using the passive radon–thoron discriminative monitor, commercially named RADUET. This paper attempts to provide an understanding of discriminative measurements of radon isotopes and to present an evidence-based roadmap.

ACS Style

Chutima Kranrod; Yuki Tamakuma; Masahiro Hosoda; Shinji Tokonami. Importance of Discriminative Measurement for Radon Isotopes and Its Utilization in the Environment and Lessons Learned from Using the RADUET Monitor. International Journal of Environmental Research and Public Health 2020, 17, 1 .

AMA Style

Chutima Kranrod, Yuki Tamakuma, Masahiro Hosoda, Shinji Tokonami. Importance of Discriminative Measurement for Radon Isotopes and Its Utilization in the Environment and Lessons Learned from Using the RADUET Monitor. International Journal of Environmental Research and Public Health. 2020; 17 (11):1.

Chicago/Turabian Style

Chutima Kranrod; Yuki Tamakuma; Masahiro Hosoda; Shinji Tokonami. 2020. "Importance of Discriminative Measurement for Radon Isotopes and Its Utilization in the Environment and Lessons Learned from Using the RADUET Monitor." International Journal of Environmental Research and Public Health 17, no. 11: 1.

Journal article
Published: 02 May 2020 in International Journal of Environmental Research and Public Health
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Air exchange through a porous medium depends partly on a pressure gradient induced in it, i.e., air-flow conditions of the outer air. Consequently, response of diffusion-type detectors to radon and thoron may vary with air-flow conditions surrounding the detectors. This effect may be significant for thoron measurement because thoron has a shorter half-life than radon. The present study examined response of diffusion-type detectors (RADUETs and one AlphaGUARD) to thoron with respect to wind speed using a thoron calibration chamber. Response of RADUETs to thoron increased with wind speed. Response of the AlphaGUARD increased with wind speed, but it became constant at a high wind speed. Different response trends to thoron between the RADUETs and the AlphaGUARD could be qualitatively explained by flow states induced by the pressure gradient in the filter or the sponge of these detectors. For RADUETs, laminar (Darcy) flow was induced in the sponge in the examined wind speed range, which meant that thoron entry into the detector increased with wind speed. For the AlphaGUARD, laminar flow was induced in the filter in the low wind speed range, whereas flow was changed to turbulent (non-Darcy) flow at a high wind speed for which thoron entry into the detector did not depend on wind speed.

ACS Style

Yasutaka Omori; Yuki Tamakuma; Eka Djatnika Nugraha; Takahito Suzuki; Miki Arian Saputra; Masahiro Hosoda; Shinji Tokonami. Impact of Wind Speed on Response of Diffusion-Type Radon-Thoron Detectors to Thoron. International Journal of Environmental Research and Public Health 2020, 17, 3178 .

AMA Style

Yasutaka Omori, Yuki Tamakuma, Eka Djatnika Nugraha, Takahito Suzuki, Miki Arian Saputra, Masahiro Hosoda, Shinji Tokonami. Impact of Wind Speed on Response of Diffusion-Type Radon-Thoron Detectors to Thoron. International Journal of Environmental Research and Public Health. 2020; 17 (9):3178.

Chicago/Turabian Style

Yasutaka Omori; Yuki Tamakuma; Eka Djatnika Nugraha; Takahito Suzuki; Miki Arian Saputra; Masahiro Hosoda; Shinji Tokonami. 2020. "Impact of Wind Speed on Response of Diffusion-Type Radon-Thoron Detectors to Thoron." International Journal of Environmental Research and Public Health 17, no. 9: 3178.

Accepted manuscript
Published: 07 February 2020 in Journal of Radiological Protection
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The radiation doses from natural radiation sources in Japan are reviewed using the latest knowledge. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and the Nuclear Safety Research Association report the annual effective doses from cosmic rays, terrestrial radiation, inhalation, and ingestion as natural sources. In this paper, the total annual effective dose from cosmic-ray exposure is evaluated as 0.29 mSv. The arithmetic mean of the annual effective dose from external exposure to terrestrial radiation is 0.33 mSv for the Japanese population using the data of nationwide surveys by the National Institute of Radiological Sciences. Previously in Japan, although three different groups have conducted nationwide indoor radon surveys using passive-type radon monitors, to date only the Japan Chemical Analysis Center (JCAC) has performed a nationwide radon survey using a unified method for radon measurements conducted indoor, outdoor, and in the workplace. Consequently, the JCAC results are used for the annual effective dose from radon and that for radon inhalation is estimated as 0.50 mSv using a current dose conversion factor. In this paper, UNSCEAR values are used for the mean indoor and outdoor thoron-progeny concentrations, and the annual effective dose from thoron is reported as 0.09 mSv. Thus, the annual effective dose from radon and thoron inhalation is 0.59 mSv. From a JCAC large-scale survey of foodstuffs, the committed effective dose from the main radionuclides in dietary intake is 0.99 mSv. Finally, the Japanese population dose from natural radiation is given as 2.2 mSv, which is similar to the reported global average of 2.4 mSv.

ACS Style

Yasutaka Omori; Masahiro Hosoda; Fumiaki Takahashi; Tetsuya Sanada; Shigekazu Hirao; Koji Ono; Masahide Furukawa. Japanese population dose from natural radiation. Journal of Radiological Protection 2020, 40, R99 -R140.

AMA Style

Yasutaka Omori, Masahiro Hosoda, Fumiaki Takahashi, Tetsuya Sanada, Shigekazu Hirao, Koji Ono, Masahide Furukawa. Japanese population dose from natural radiation. Journal of Radiological Protection. 2020; 40 (3):R99-R140.

Chicago/Turabian Style

Yasutaka Omori; Masahiro Hosoda; Fumiaki Takahashi; Tetsuya Sanada; Shigekazu Hirao; Koji Ono; Masahide Furukawa. 2020. "Japanese population dose from natural radiation." Journal of Radiological Protection 40, no. 3: R99-R140.

Journal article
Published: 27 December 2019 in Japanese Journal of Health Physics
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Masahiro Hosoda. Report on a Technical Meeting on the Implications of the New Dose Conversion Factors for Radon. Japanese Journal of Health Physics 2019, 54, 226 -230.

AMA Style

Masahiro Hosoda. Report on a Technical Meeting on the Implications of the New Dose Conversion Factors for Radon. Japanese Journal of Health Physics. 2019; 54 (4):226-230.

Chicago/Turabian Style

Masahiro Hosoda. 2019. "Report on a Technical Meeting on the Implications of the New Dose Conversion Factors for Radon." Japanese Journal of Health Physics 54, no. 4: 226-230.

Comparative study
Published: 01 January 2019 in Health Physics
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A performance test was carried out using five different gamma-ray spectrometers applicable to thyroid monitoring. The energy resolution and efficiency for 7.6-cm × 7.6-cm NaI(Tl), 5.1-cm × 5.1-cm CeBr3, 3.8-cm × 3.8-cm SrI2(Eu), and 2.5-cm × 2.5-cm SrI2(Eu) gamma-ray scintillation spectrometers and a CdTe gamma-ray semiconductor spectrometer were evaluated using the Oak Ridge Institute for Nuclear Studies thyroid-neck phantom with a mock 131I source for prompt thyroid monitoring after a nuclear emergency. The respective energy resolutions of the full-energy peak for ~0.360 MeV of 3.8-cm × 3.8-cm SrI2(Eu) and 2.5-cm × 2.5-cm SrI2(Eu) scintillation spectrometers were 4.2% and 4.3%, and these values were very close to the value obtained by the CdTe semiconductor spectrometer. The efficiencies of four of the gamma-ray spectrometers were compared based on the efficiency of the 7.6-cm × 7.6-cm NaI(Tl) scintillation spectrometer at 0 cm from the phantom surface, and these values were ~70% for 5.1-cm × 5.1-cm CeBr3, ~30% for 3.8-cm × 3.8-cm SrI2(Eu), 10% for 2.5-cm × 2.5-cm SrI2(Eu) and 2% for 1-cm2 × 0.1-cm CdTe. Furthermore, the detection limits at various dose rates for the four gamma-ray scintillation spectrometers were evaluated using the method based on International Organization for Standardization publication ISO 11929:2010.

ACS Style

Masahiro Hosoda; Kazuki Iwaoka; Shinji Tokonami; Yuki Tamakuma; Yoshitaka Shiroma; Takahiro Fukuhara; Yusuke Imajyo; Jun Taniguchi; Naofumi Akata; Minoru Osanai; Takakiyo Tsujiguchi; Masaru Yamaguchi; Ikuo Kashiwakura. Comparative Study of Performance using Five Different Gamma-ray Spectrometers for Thyroid Monitoring under Nuclear Emergency Situations. Health Physics 2019, 116, 81 -87.

AMA Style

Masahiro Hosoda, Kazuki Iwaoka, Shinji Tokonami, Yuki Tamakuma, Yoshitaka Shiroma, Takahiro Fukuhara, Yusuke Imajyo, Jun Taniguchi, Naofumi Akata, Minoru Osanai, Takakiyo Tsujiguchi, Masaru Yamaguchi, Ikuo Kashiwakura. Comparative Study of Performance using Five Different Gamma-ray Spectrometers for Thyroid Monitoring under Nuclear Emergency Situations. Health Physics. 2019; 116 (1):81-87.

Chicago/Turabian Style

Masahiro Hosoda; Kazuki Iwaoka; Shinji Tokonami; Yuki Tamakuma; Yoshitaka Shiroma; Takahiro Fukuhara; Yusuke Imajyo; Jun Taniguchi; Naofumi Akata; Minoru Osanai; Takakiyo Tsujiguchi; Masaru Yamaguchi; Ikuo Kashiwakura. 2019. "Comparative Study of Performance using Five Different Gamma-ray Spectrometers for Thyroid Monitoring under Nuclear Emergency Situations." Health Physics 116, no. 1: 81-87.

Journal article
Published: 30 September 2018 in International Journal of Environmental Research and Public Health
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Long-term exposure to radon has been determined to be the second leading cause of lung cancer after tobacco smoking. However, an in-depth study of this topic has not been explicitly carried out in Chiang Mai (Thailand). This paper presents the results of an indoor radon level measurement campaign in dwellings of Chiang Mai using total of 110 detectors (CR-39) during one year. The results show that the average radon levels varied from 35 to 219 Bq/m3, with an overall average of 57 Bq/m3. The finding also shows that the average value is higher than the global average value of 39 Bq/m3. In addition, to examine the cause of lung cancer development among people with risk of chronic exposure to radon during their lifetime, 35 non-smoker lung cancer patients and 33 healthy nonsmokers were analyzed for telomere length. As expected, telomere length was significantly shorter in lung cancer patients than in healthy nonsmokers. Among healthy nonsmokers, the telomere length was significantly shorter in a high radon group than in an unaffected low radon group. To the best of our knowledge, our research provides the first attempt in describing the shortened telomeres in areas with high levels of environmental radon that might be related to lung cancer development.

ACS Style

Narongchai Autsavapromporn; Pitchayaponne Klunklin; Chalat Threeratana; Wirote Tuntiwechapikul; Masahiro Hosoda; Shinji Tokonami. Short Telomere Length as a Biomarker Risk of Lung Cancer Development Induced by High Radon Levels: A Pilot Study. International Journal of Environmental Research and Public Health 2018, 15, 2152 .

AMA Style

Narongchai Autsavapromporn, Pitchayaponne Klunklin, Chalat Threeratana, Wirote Tuntiwechapikul, Masahiro Hosoda, Shinji Tokonami. Short Telomere Length as a Biomarker Risk of Lung Cancer Development Induced by High Radon Levels: A Pilot Study. International Journal of Environmental Research and Public Health. 2018; 15 (10):2152.

Chicago/Turabian Style

Narongchai Autsavapromporn; Pitchayaponne Klunklin; Chalat Threeratana; Wirote Tuntiwechapikul; Masahiro Hosoda; Shinji Tokonami. 2018. "Short Telomere Length as a Biomarker Risk of Lung Cancer Development Induced by High Radon Levels: A Pilot Study." International Journal of Environmental Research and Public Health 15, no. 10: 2152.

Review
Published: 01 September 2018 in Journal of Environmental Radioactivity
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222Rn, 220Rn and their short-lived progenies are well known radioactive indoor pollutants, identified as the leading environmental cause of lung cancer next to smoking. Apart from the conventional measurement methods, numerical modeling methods are developed to simulate their physical and decay processes in 222Rn and 220Rn's life cycle, estimate their levels, concentration distributions, as well as effects of control strategies in the indoor environment. In this article, we summarized the numerical models used to illustrate the physical processes of each source of 222Rn and 220Rn entry into the indoor environment, and the application of Jacobi room models and CFD (Computational Fluid Dynamic) models used to present the behaviors of indoor 222Rn, 220Rn and their progenies. Furthermore, we consider that the development of numerical modeling of 222Rn and 220Rn would have a bright prospect in the directions of stochastic methods based on a steady-state model, the fine simulation of the time-dependent model as well as the multi-dimension model.

ACS Style

Jun Hu; Guosheng Yang; Miklós Hegedűs; Kazuki Iwaoka; Masahiro Hosoda; Shinji Tokonami. Numerical modeling of the sources and behaviors of 222Rn, 220Rn and their progenies in the indoor environment—A review. Journal of Environmental Radioactivity 2018, 189, 40 -47.

AMA Style

Jun Hu, Guosheng Yang, Miklós Hegedűs, Kazuki Iwaoka, Masahiro Hosoda, Shinji Tokonami. Numerical modeling of the sources and behaviors of 222Rn, 220Rn and their progenies in the indoor environment—A review. Journal of Environmental Radioactivity. 2018; 189 ():40-47.

Chicago/Turabian Style

Jun Hu; Guosheng Yang; Miklós Hegedűs; Kazuki Iwaoka; Masahiro Hosoda; Shinji Tokonami. 2018. "Numerical modeling of the sources and behaviors of 222Rn, 220Rn and their progenies in the indoor environment—A review." Journal of Environmental Radioactivity 189, no. : 40-47.

Journal article
Published: 12 June 2018 in Plasma and Fusion Research
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We have developed a rapid sampling system for measuring the tritium in atmospheric water vapor. The system consists of a high-efficiency particulate air filter cartridge, an oil-free compressor, a water-vapor-separating module with hollow fiber membranes, two cold traps, and an oil-free rotary pump. Compressed air (0.4 - 0.7MPa) is introduced into the water-vapor-separation module, which consists of a stainless steel column containing polyimide membrane tubes. Water vapor permeates through the tubes and is collected by cold traps cooled with dry ice and ethanol. The module is heated with a flexible heater to control its temperature. We have determined the recovery yields under various sampling conditions and find that this system can collect atmospheric water vapor with a recovery yield of >99%. This system can thus be a useful tool for understanding short-term observations of tritium in atmospheric water vapor.

ACS Style

Naofumi Akata; Hideki Kakiuchi; Masahiro Tanaka; Nagayoshi Shima; Yoshitaka Shiroma; Shinji Tokonami; Masahiro Hosoda; Yoshio Ishikawa; Masahide Furukawa; Tetsuya Sanada. Development of Rapid Sampling System of Atmospheric Water Vapor for Tritium Measurement. Plasma and Fusion Research 2018, 13, 3405064 -3405064.

AMA Style

Naofumi Akata, Hideki Kakiuchi, Masahiro Tanaka, Nagayoshi Shima, Yoshitaka Shiroma, Shinji Tokonami, Masahiro Hosoda, Yoshio Ishikawa, Masahide Furukawa, Tetsuya Sanada. Development of Rapid Sampling System of Atmospheric Water Vapor for Tritium Measurement. Plasma and Fusion Research. 2018; 13 ():3405064-3405064.

Chicago/Turabian Style

Naofumi Akata; Hideki Kakiuchi; Masahiro Tanaka; Nagayoshi Shima; Yoshitaka Shiroma; Shinji Tokonami; Masahiro Hosoda; Yoshio Ishikawa; Masahide Furukawa; Tetsuya Sanada. 2018. "Development of Rapid Sampling System of Atmospheric Water Vapor for Tritium Measurement." Plasma and Fusion Research 13, no. : 3405064-3405064.

Journal article
Published: 01 January 2018 in Japanese Journal of Health Physics
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ACS Style

Naofumi Akata; Yoshitaka Shiroma; Masahide Furukawa; Akemi Kato; Hideki Kakiuchi; Masahiro Hosoda; Yutaka Kanai; Fumitaka Yanagisawa. Concentrations of Chemical Components, Including 210Pb, Present in Aerosols Collected at Naha, Okinawa Prefecture, a Sub-tropical Region of Japan. Japanese Journal of Health Physics 2018, 53, 17 -22.

AMA Style

Naofumi Akata, Yoshitaka Shiroma, Masahide Furukawa, Akemi Kato, Hideki Kakiuchi, Masahiro Hosoda, Yutaka Kanai, Fumitaka Yanagisawa. Concentrations of Chemical Components, Including 210Pb, Present in Aerosols Collected at Naha, Okinawa Prefecture, a Sub-tropical Region of Japan. Japanese Journal of Health Physics. 2018; 53 (1):17-22.

Chicago/Turabian Style

Naofumi Akata; Yoshitaka Shiroma; Masahide Furukawa; Akemi Kato; Hideki Kakiuchi; Masahiro Hosoda; Yutaka Kanai; Fumitaka Yanagisawa. 2018. "Concentrations of Chemical Components, Including 210Pb, Present in Aerosols Collected at Naha, Okinawa Prefecture, a Sub-tropical Region of Japan." Japanese Journal of Health Physics 53, no. 1: 17-22.