Pub Date : 2022-03-30DOI: 10.14407/jrpr.2021.00220
M. Kowatari, K. Nagamoto, K. Nakagami, Y. Tanimura, T. Moritake, N. Kunugita
Background: For proper monitoring of the eye lens dose, an appropriate calibration factor of a dosimeter and information about the mean energies of X-rays are indispensable. The scattered X-ray energy spectra should be well characterized in medical practices where eye lenses of medical staffs might be high.Materials and Methods: Scattered X-ray energy spectra were experimentally derived for three different types of X-ray diagnostic and therapeutic equipment, i.e., the computed tomography (CT) scan, the angiography and the fluoroscopy. A commercially available CdZnTe (CZT) spectrometer with a lead collimator was employed for the measurement of scattered X-rays, which was performed in the usual manner.Results and Discussion: From the obtained energy spectra, the mean energies of the scattered X-rays lied between 40 and 60 keV. This also agreed with that obtained by the conventional half value layer method.Conclusion: The scattered X-rays to which medical workers may be exposed in the region around the eyes were characterized by means of spectrometry. The obtained mean energies of the scattered X-rays were found to match the flat region of the dosimeter response.
{"title":"Experimental Evaluation of Scattered X-Ray Spectra due to X-Ray Therapeutic and Diagnosis Equipment for Eye Lens Dosimetry of Medical Staff","authors":"M. Kowatari, K. Nagamoto, K. Nakagami, Y. Tanimura, T. Moritake, N. Kunugita","doi":"10.14407/jrpr.2021.00220","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00220","url":null,"abstract":"Background: For proper monitoring of the eye lens dose, an appropriate calibration factor of a dosimeter and information about the mean energies of X-rays are indispensable. The scattered X-ray energy spectra should be well characterized in medical practices where eye lenses of medical staffs might be high.Materials and Methods: Scattered X-ray energy spectra were experimentally derived for three different types of X-ray diagnostic and therapeutic equipment, i.e., the computed tomography (CT) scan, the angiography and the fluoroscopy. A commercially available CdZnTe (CZT) spectrometer with a lead collimator was employed for the measurement of scattered X-rays, which was performed in the usual manner.Results and Discussion: From the obtained energy spectra, the mean energies of the scattered X-rays lied between 40 and 60 keV. This also agreed with that obtained by the conventional half value layer method.Conclusion: The scattered X-rays to which medical workers may be exposed in the region around the eyes were characterized by means of spectrometry. The obtained mean energies of the scattered X-rays were found to match the flat region of the dosimeter response.","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76249998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-30DOI: 10.14407/jrpr.2021.00227
Bo-Lun Lai, Szu-Li Chang, R. Sheu
Background: There are several proton therapy facilities in operation or planned in Taiwan, and these facilities are anticipated to not only treat cancer but also provide beam services to the industry or academia. The simplified approach based on the Monte Carlo-based data sets (source terms and attenuation lengths) with the point-source line-of-sight approximation is friendly in the design stage of the proton therapy facilities because it is intuitive and easy to use. The purpose of this study is to expand the Monte Carlo-based data sets to allow the simplified approach to cover the application of proton beams more widely.Materials and Methods: In this work, the MCNP6 Monte Carlo code was used in three simulations to achieve the purpose, including the neutron yield calculation, Monte Carlo-based data sets generation, and dose assessment in simple cases to demonstrate the effectiveness of the generated data sets.Results and Discussion: The consistent comparison of the simplified approach and Monte Carlo simulation results show the effectiveness and advantage of applying the data set to a quick shielding design and conservative dose assessment for proton therapy facilities.Conclusion: This study has expanded the existing Monte Carlo-based data set to allow the simplified approach method to be used for dose assessment or shielding design for beam services in proton therapy facilities. It should be noted that the default model of the MCNP6 is no longer the Bertini model but the CEM (cascade-exciton model), therefore, the results of the simplified approach will be more conservative when it was used to do the double confirmation of the final shielding design.
{"title":"Demonstration of the Effectiveness of Monte Carlo-Based Data Sets with the Simplified Approach for Shielding Design of a Laboratory with the Therapeutic Level Proton Beam","authors":"Bo-Lun Lai, Szu-Li Chang, R. Sheu","doi":"10.14407/jrpr.2021.00227","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00227","url":null,"abstract":"Background: There are several proton therapy facilities in operation or planned in Taiwan, and these facilities are anticipated to not only treat cancer but also provide beam services to the industry or academia. The simplified approach based on the Monte Carlo-based data sets (source terms and attenuation lengths) with the point-source line-of-sight approximation is friendly in the design stage of the proton therapy facilities because it is intuitive and easy to use. The purpose of this study is to expand the Monte Carlo-based data sets to allow the simplified approach to cover the application of proton beams more widely.Materials and Methods: In this work, the MCNP6 Monte Carlo code was used in three simulations to achieve the purpose, including the neutron yield calculation, Monte Carlo-based data sets generation, and dose assessment in simple cases to demonstrate the effectiveness of the generated data sets.Results and Discussion: The consistent comparison of the simplified approach and Monte Carlo simulation results show the effectiveness and advantage of applying the data set to a quick shielding design and conservative dose assessment for proton therapy facilities.Conclusion: This study has expanded the existing Monte Carlo-based data set to allow the simplified approach method to be used for dose assessment or shielding design for beam services in proton therapy facilities. It should be noted that the default model of the MCNP6 is no longer the Bertini model but the CEM (cascade-exciton model), therefore, the results of the simplified approach will be more conservative when it was used to do the double confirmation of the final shielding design.","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80632721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-30DOI: 10.14407/jrpr.2021.00031
A. Srivastava, V. Chahar, Neeraj Chauhan, D. Krupp, U. Scherer
Background: Epidemiological observations such as mental retardation, physical deformities, etc., in children besides different types of cancer in the adult population of the Malwa region have been reported. The present study is designed to get insight into the role of naturally occurring radioactive material (NORM) in causing detrimental health effects observed in the general population of this region.Materials and Methods: Deep soil samples were collected from different locations in the Malwa region. Their activity concentrations were determined using low-level background gammaray spectrometry. High efficiency and high purity germanium detector capped in a lead-shielded chamber having a resolution of 1.8 keV at 1,173 keV and 2.0 keV at the 1,332 keV line of 60Co was used in the present work. Data were evaluated with Genie-2000 software.Results and Discussion: Mean activity concentrations of 238U, 232Th, and 40K in deep soil were found to be 101.3 Bq/kg, 65.8 Bq/kg, and 688.6 Bq/kg, respectively. The mean activity concentration of 238U was found to be three and half times higher than the global average prescribed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). It was further observed that the activity concentration of 232Th and 40K has a magnitude that is nearly one and half times higher than the global average prescribed by UNSCEAR. In addition, the radioisotope 137Cs which is likely to have its origin in radiation fallout was also observed. It is postulated that the NORM present in high quantity in deep soil somehow get mobilized into the water aquifers used by the general population and thereby causing harmful health problems.Conclusion: It can be stated that the present work has been able to demonstrate the use of low background gamma-ray spectrometry to understand the role of NORM in causing health-related effects in a general population of the Malwa region of Punjab, India.
{"title":"Study of Naturally Occurring Radioactive Material Present in Deep Soil of the Malwa Region of Punjab State of India Using Low Level Background Gamma-Ray Spectrometry","authors":"A. Srivastava, V. Chahar, Neeraj Chauhan, D. Krupp, U. Scherer","doi":"10.14407/jrpr.2021.00031","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00031","url":null,"abstract":"Background: Epidemiological observations such as mental retardation, physical deformities, etc., in children besides different types of cancer in the adult population of the Malwa region have been reported. The present study is designed to get insight into the role of naturally occurring radioactive material (NORM) in causing detrimental health effects observed in the general population of this region.Materials and Methods: Deep soil samples were collected from different locations in the Malwa region. Their activity concentrations were determined using low-level background gammaray spectrometry. High efficiency and high purity germanium detector capped in a lead-shielded chamber having a resolution of 1.8 keV at 1,173 keV and 2.0 keV at the 1,332 keV line of 60Co was used in the present work. Data were evaluated with Genie-2000 software.Results and Discussion: Mean activity concentrations of 238U, 232Th, and 40K in deep soil were found to be 101.3 Bq/kg, 65.8 Bq/kg, and 688.6 Bq/kg, respectively. The mean activity concentration of 238U was found to be three and half times higher than the global average prescribed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). It was further observed that the activity concentration of 232Th and 40K has a magnitude that is nearly one and half times higher than the global average prescribed by UNSCEAR. In addition, the radioisotope 137Cs which is likely to have its origin in radiation fallout was also observed. It is postulated that the NORM present in high quantity in deep soil somehow get mobilized into the water aquifers used by the general population and thereby causing harmful health problems.Conclusion: It can be stated that the present work has been able to demonstrate the use of low background gamma-ray spectrometry to understand the role of NORM in causing health-related effects in a general population of the Malwa region of Punjab, India.","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88627083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-29DOI: 10.14407/jrpr.2021.00024
Chul Hang Kim, H. Choi, K. Kang, B. Jeong, Hojin Jeong, I. Ha, J. Song
1Department of Radiation Oncology, Gyeongsang National University Changwon Hospital, Gyeongsang National University College of Medicine, Changwon, Korea; 2Department of Biomedical Engineering, Pusan National University, Pusan, Korea; 3Institute of Health Science, School of Medicine, Gyeongsang National University, Jinju, Korea; 4Department of Radiation Oncology, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju, Korea; 5Department of Radiation Oncology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
{"title":"Development and Evaluation of the Utility of a Respiratory Monitoring and Visual Feedback System for Radiotherapy Using Machine Vision Technology","authors":"Chul Hang Kim, H. Choi, K. Kang, B. Jeong, Hojin Jeong, I. Ha, J. Song","doi":"10.14407/jrpr.2021.00024","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00024","url":null,"abstract":"1Department of Radiation Oncology, Gyeongsang National University Changwon Hospital, Gyeongsang National University College of Medicine, Changwon, Korea; 2Department of Biomedical Engineering, Pusan National University, Pusan, Korea; 3Institute of Health Science, School of Medicine, Gyeongsang National University, Jinju, Korea; 4Department of Radiation Oncology, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju, Korea; 5Department of Radiation Oncology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84707125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-23DOI: 10.14407/jrpr.2022.00009
Hee Reyoung
Cadmium zinc telluride (CZT) is the most promising material to detect X-ray and gamma-ray due to its high detection efficiency, good energy resolution, and operability at room temperature without any cooling device. However, detector responses of the CZT depend on the interaction position because of the distributions of weighting potential in a planar electrode structure and material defects, and it causes the degradation of the performance. We developed a detection system based on a 3D position-sensitive detector to overcome this problem. A 5 × 5 × 12 mm3 CZT was used, and the virtual Frisch-grid (VFG) method was applied. 3D position information was calculated by signals from the anode, cathode, and side electrodes. The detector responses were corrected by the position information, and as a result, the energy resolution of 0.83% at 662 keV was achieved. We developed a prototype Compton camera by expanding the single VFG CZT detector to a 2 × 2 array. This array structure allows us to use small but high-yielding crystals, so a large-area detection system with a low cost can be achievable. Four 6 × 6 × 19 mm3 CZTs and a commercialized signal processing system were used. Positional information acquisition and response correction were performed the same way as the previous system. Various sources were used for spectroscopy, and the energy resolutions at 356, 511, 662, 1,275, and 1,332 keV were 3.17, 2.37, 2.03, 1.49, and 1.14%, respectively. In Compton imaging experiments, single and multiple sources at various positions were measured, and the weighted list-mode MLEM method was applied for image reconstruction. The results showed that our Compton camera could correctly reconstruct the source positions of either single or multiple sources. The intrinsic efficiency and spatial resolution evaluated by single 137Cs results were (1.43 ± 0.28) × 10-3 and 16.42 ± 5.35°, respectively. It was also identified that the different sources could be distinguished by applying energy windows. Name of graduate: Lee, Chanki Affiliation: Department of Nuclear Engineering/Ulsan National Institute of Science and Technology/Korea Graduation date: Feb. 2022 Degree: Doctor of Philosophy Name of academic advisor: Kim, Hee Reyoung Title of thesis: In Situ YAlO3(Ce) Gamma Spectrometry System for Underwater Survey by Remotely Operated Vehicle Abstract: Rapid surveys and assessments of environmental radioactivity and radiation doses are required for efficient and effective response to radiological emergencies. Emergency responses under underwater conditions to illegal ocean dumping, accidents, or sabotage of marine nuclear reactors are probably going to increase in the future. Therefore, in this study, we designed, developed, and tested a mechanical, chemical, and radiologically robust in situ YAlO3(Ce) gamma spectrometer survey system, that is remotely operated by an unmanned vehicle to be used for short-range and high-dose contaminations. In particular, the system is optimally
{"title":"List of Recent Graduates","authors":"Hee Reyoung","doi":"10.14407/jrpr.2022.00009","DOIUrl":"https://doi.org/10.14407/jrpr.2022.00009","url":null,"abstract":"Cadmium zinc telluride (CZT) is the most promising material to detect X-ray and gamma-ray due to its high detection efficiency, good energy resolution, and operability at room temperature without any cooling device. However, detector responses of the CZT depend on the interaction position because of the distributions of weighting potential in a planar electrode structure and material defects, and it causes the degradation of the performance. We developed a detection system based on a 3D position-sensitive detector to overcome this problem. A 5 × 5 × 12 mm3 CZT was used, and the virtual Frisch-grid (VFG) method was applied. 3D position information was calculated by signals from the anode, cathode, and side electrodes. The detector responses were corrected by the position information, and as a result, the energy resolution of 0.83% at 662 keV was achieved. We developed a prototype Compton camera by expanding the single VFG CZT detector to a 2 × 2 array. This array structure allows us to use small but high-yielding crystals, so a large-area detection system with a low cost can be achievable. Four 6 × 6 × 19 mm3 CZTs and a commercialized signal processing system were used. Positional information acquisition and response correction were performed the same way as the previous system. Various sources were used for spectroscopy, and the energy resolutions at 356, 511, 662, 1,275, and 1,332 keV were 3.17, 2.37, 2.03, 1.49, and 1.14%, respectively. In Compton imaging experiments, single and multiple sources at various positions were measured, and the weighted list-mode MLEM method was applied for image reconstruction. The results showed that our Compton camera could correctly reconstruct the source positions of either single or multiple sources. The intrinsic efficiency and spatial resolution evaluated by single 137Cs results were (1.43 ± 0.28) × 10-3 and 16.42 ± 5.35°, respectively. It was also identified that the different sources could be distinguished by applying energy windows. Name of graduate: Lee, Chanki Affiliation: Department of Nuclear Engineering/Ulsan National Institute of Science and Technology/Korea Graduation date: Feb. 2022 Degree: Doctor of Philosophy Name of academic advisor: Kim, Hee Reyoung Title of thesis: In Situ YAlO3(Ce) Gamma Spectrometry System for Underwater Survey by Remotely Operated Vehicle Abstract: Rapid surveys and assessments of environmental radioactivity and radiation doses are required for efficient and effective response to radiological emergencies. Emergency responses under underwater conditions to illegal ocean dumping, accidents, or sabotage of marine nuclear reactors are probably going to increase in the future. Therefore, in this study, we designed, developed, and tested a mechanical, chemical, and radiologically robust in situ YAlO3(Ce) gamma spectrometer survey system, that is remotely operated by an unmanned vehicle to be used for short-range and high-dose contaminations. In particular, the system is optimally","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86098494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-05DOI: 10.14407/jrpr.2021.00311
Y. Lim
Background: Radiation exposure can occur as a result of occupational activities utilizing sources of radiation. The average level of occupational exposure is generally similar to the global average, but some workers receive more than this. In this study, the occupational exposure data for workers in Korea to check the recent trend of radiation exposure. Materials and Methods: The data collection and analysis are carried out by two separate periods based on the United Nations Scientific Committee on the Effects of Atomic Radiation (UN-SCEAR) survey. One is the year 2003 to 2014 for a recent survey, and the other is 2015 to 2019. All available data were collected by annual reports from radiation dose registry organizations. Results and Discussion: The annual dose over the record level to the total workers did not change much compared with the total increasing number of workers in this period. The dose to the nuclear fuel cycle field has a tendency to decrease. It resulted from the efforts of radiation dose reduction with high technology introduced to this area. Also, it is important result that the radiation dose to the workers in radiography is remarkably reduced. Conclusion: The number of radiation workers and average doses were analyzed for occupational categories in Korea. It still needs cooperative efforts between the dose registry organizations for the efficient dose management of Korean radiation workers.
{"title":"Recent Trend of Occupational Exposure to Ionizing Radiation in Korea, 2015–2019","authors":"Y. Lim","doi":"10.14407/jrpr.2021.00311","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00311","url":null,"abstract":"Background: Radiation exposure can occur as a result of occupational activities utilizing sources of radiation. The average level of occupational exposure is generally similar to the global average, but some workers receive more than this. In this study, the occupational exposure data for workers in Korea to check the recent trend of radiation exposure. Materials and Methods: The data collection and analysis are carried out by two separate periods based on the United Nations Scientific Committee on the Effects of Atomic Radiation (UN-SCEAR) survey. One is the year 2003 to 2014 for a recent survey, and the other is 2015 to 2019. All available data were collected by annual reports from radiation dose registry organizations. Results and Discussion: The annual dose over the record level to the total workers did not change much compared with the total increasing number of workers in this period. The dose to the nuclear fuel cycle field has a tendency to decrease. It resulted from the efforts of radiation dose reduction with high technology introduced to this area. Also, it is important result that the radiation dose to the workers in radiography is remarkably reduced. Conclusion: The number of radiation workers and average doses were analyzed for occupational categories in Korea. It still needs cooperative efforts between the dose registry organizations for the efficient dose management of Korean radiation workers.","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86399178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-30DOI: 10.14407/jrpr.2021.00171
Y. Sanada, Mutsushi Ishida, K. Yoshimura, S. Mikami
Background: The radionuclides released by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident 9 years ago are still being monitored by various research teams and the Japanese government. Comparison of different surveys’ results could help evaluate the exposure doses and the mechanism of radiocesium behavior in the urban environment in the area. In this study, we clarified the relationship between land use and temporal changes in the ambient dose rates (air dose rates) using big data.Materials and Methods: We set a series of 1 × 1 km2 meshes within the 80 km zone of the FDNPP to compare the different survey results. We then prepared an analysis dataset from all survey meshes to analyze the temporal change in the air dose rate. The selected meshes included data from all survey types (airborne, fixed point, backpack, and carborne) obtained through the all-time survey campaigns.Results and Discussion: The characteristics of each survey’s results were then evaluated using this dataset, as they depended on the measurement object. The dataset analysis revealed that, for example, the results of the carborne survey were smaller than those of the other surveys because the field of view of the carborne survey was limited to paved roads. The location factor of different land uses was also evaluated considering the characteristics of the four survey methods. Nine years after the FDNPP accident, the location factor ranged from 0.26 to 0.49, while the half-life of the air dose rate ranged from 1.2 to 1.6.Conclusion: We found that the decreasing trend in the air dose rate of the FDNPP accident was similar to the results obtained after the Chernobyl accident. These parameters will be useful for the prediction of the future exposure dose at the post-accident.
{"title":"Comparison of Dose Rates from Four Surveys around the Fukushima Daiichi Nuclear Power Plant for Location Factor Evaluation","authors":"Y. Sanada, Mutsushi Ishida, K. Yoshimura, S. Mikami","doi":"10.14407/jrpr.2021.00171","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00171","url":null,"abstract":"Background: The radionuclides released by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident 9 years ago are still being monitored by various research teams and the Japanese government. Comparison of different surveys’ results could help evaluate the exposure doses and the mechanism of radiocesium behavior in the urban environment in the area. In this study, we clarified the relationship between land use and temporal changes in the ambient dose rates (air dose rates) using big data.Materials and Methods: We set a series of 1 × 1 km2 meshes within the 80 km zone of the FDNPP to compare the different survey results. We then prepared an analysis dataset from all survey meshes to analyze the temporal change in the air dose rate. The selected meshes included data from all survey types (airborne, fixed point, backpack, and carborne) obtained through the all-time survey campaigns.Results and Discussion: The characteristics of each survey’s results were then evaluated using this dataset, as they depended on the measurement object. The dataset analysis revealed that, for example, the results of the carborne survey were smaller than those of the other surveys because the field of view of the carborne survey was limited to paved roads. The location factor of different land uses was also evaluated considering the characteristics of the four survey methods. Nine years after the FDNPP accident, the location factor ranged from 0.26 to 0.49, while the half-life of the air dose rate ranged from 1.2 to 1.6.Conclusion: We found that the decreasing trend in the air dose rate of the FDNPP accident was similar to the results obtained after the Chernobyl accident. These parameters will be useful for the prediction of the future exposure dose at the post-accident.","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80067387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-29DOI: 10.14407/jrpr.2021.00178
Chanki Lee, H. Kim
Materials and Methods: Regarding this, we test and suggest a measurement technique for gross alpha/beta and 90Sr activities in surface soil based on a mobile ZnS(Ag)/PVT (polyvinyltoluene) array and a handheld PVT rod, respectively. To detect 90Sr selectively in soil mixed with naturally occurring radioactive materials, chosen energy channel counts from the multichannel analyzers were used instead of whole channel counts. Soil samples contaminated with exempt liquid 90Sr with 1 Bq· g-1, 3 Bq· g-1, and 10 Bq· g-1 were prepared and hardened by flocculation.
{"title":"Preliminary Study on Rapid Measurement of Gross Alpha/Beta and 90Sr Activities in Surface Soil by Mobile ZnS(Ag)/PTV Array and Handheld PVT Rod with Gated Energy Channels","authors":"Chanki Lee, H. Kim","doi":"10.14407/jrpr.2021.00178","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00178","url":null,"abstract":"Materials and Methods: Regarding this, we test and suggest a measurement technique for gross alpha/beta and 90Sr activities in surface soil based on a mobile ZnS(Ag)/PVT (polyvinyltoluene) array and a handheld PVT rod, respectively. To detect 90Sr selectively in soil mixed with naturally occurring radioactive materials, chosen energy channel counts from the multichannel analyzers were used instead of whole channel counts. Soil samples contaminated with exempt liquid 90Sr with 1 Bq· g-1, 3 Bq· g-1, and 10 Bq· g-1 were prepared and hardened by flocculation.","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75407634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-29DOI: 10.14407/jrpr.2021.00164
K. Tagami, S. Uchida
Background: This study was carried out to provide environmental transfer parameter values to estimate activity concentrations of these radionuclides in agricultural crops when direct contamination occurred. Materials and Methods: Mass interception fractions ( F B s) and weathering half-lives ( T w s) of 131 I and radiocesium were calculated using openly available monitoring data obtained after the Fukushima Daiichi Nuclear Power Plant accident. F B is the ratio between the initial radioactivity concentration of a radionuclide retained by the edible part of the plant (Bq ‧ kg -1 fresh weight [FW]) and the amount of deposited radionuclide in that area (Bq ‧ m -2 ). T w values can be calculated using activity concentrations of crops decreased with time after the initial contamination. Results and Discussion: Calculated F B and T w values for 131 I and radiocesium were mostly obtained for leafy vegetables. The analytical results showed that there was no difference of F B s between 131 I and radiocesium by t -test; geometric mean values for leafy vegetables cultivated under outdoor conditions were 0.058 and 0.12 m 2 ‧ kg -1 FW, respectively. Geometric mean T w value of 131 I in leafy vegetables grown under outdoor conditions was 8.6 days, and that of radiocesium was 6.6 days; there was no significant difference between T w values of these radionuclides by Wilcoxon rank sum test. Conclusion: There was no difference between 131 I and radiocesium for F B s and T w s. By using these factors, we would be able to carry out a rough estimation of the activity concentrations of 131 I and radiocesium in the edible part of leafy crops when a nuclear accident occurred.
背景:本研究旨在提供环境转移参数值，以估计在直接污染发生时这些放射性核素在农作物中的活度浓度。材料和方法:利用福岛第一核电站事故后获得的公开监测数据，计算了131 I和放射性元素的质量拦截分数(F B s)和风化半衰期(T w s)。fb为植物可食用部分所保留的放射性核素的初始放射性浓度(Bq·kg -1鲜重[FW])与在该地区沉积的放射性核素量(Bq·kg -2)之比。tw值可以通过初始污染后随时间减少的作物活性浓度来计算。结果与讨论:131 I和放射性元素的F - B和T - w计算值主要来自叶菜。经t检验，结果表明:131i与放射性铯的F - B - s无显著性差异;室外栽培叶菜的几何平均值分别为0.058和0.12 m 2·kg -1 FW。室外条件下叶菜131 I的几何平均T w值为8.6 d，放射性铯的几何平均T w值为6.6 d;经Wilcoxon秩和检验，这些放射性核素的tw值之间无显著差异。结论:放射性元素131 I和放射性元素放射性元素在F B s和T w s中没有差异，利用这些因子可以对核事故发生时叶状作物可食用部位放射性元素131 I和放射性元素的活性浓度进行粗略估计。
{"title":"Mass Interception Fractions and Weathering Half-lives of Iodine-131 and Radiocesium in Leafy Vegetables Observed after the Fukushima Daiichi Nuclear Power Plant Accident","authors":"K. Tagami, S. Uchida","doi":"10.14407/jrpr.2021.00164","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00164","url":null,"abstract":"Background: This study was carried out to provide environmental transfer parameter values to estimate activity concentrations of these radionuclides in agricultural crops when direct contamination occurred. Materials and Methods: Mass interception fractions ( F B s) and weathering half-lives ( T w s) of 131 I and radiocesium were calculated using openly available monitoring data obtained after the Fukushima Daiichi Nuclear Power Plant accident. F B is the ratio between the initial radioactivity concentration of a radionuclide retained by the edible part of the plant (Bq ‧ kg -1 fresh weight [FW]) and the amount of deposited radionuclide in that area (Bq ‧ m -2 ). T w values can be calculated using activity concentrations of crops decreased with time after the initial contamination. Results and Discussion: Calculated F B and T w values for 131 I and radiocesium were mostly obtained for leafy vegetables. The analytical results showed that there was no difference of F B s between 131 I and radiocesium by t -test; geometric mean values for leafy vegetables cultivated under outdoor conditions were 0.058 and 0.12 m 2 ‧ kg -1 FW, respectively. Geometric mean T w value of 131 I in leafy vegetables grown under outdoor conditions was 8.6 days, and that of radiocesium was 6.6 days; there was no significant difference between T w values of these radionuclides by Wilcoxon rank sum test. Conclusion: There was no difference between 131 I and radiocesium for F B s and T w s. By using these factors, we would be able to carry out a rough estimation of the activity concentrations of 131 I and radiocesium in the edible part of leafy crops when a nuclear accident occurred.","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84795409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-25DOI: 10.14407/jrpr.2021.00066
Tae-Eun Kwon, Seokwon Yoon, Wi-Ho Ha, Yoonsun Chung, Y. Jin
Background: The International Commission on Radiological Protection is preparing to pro-vide reference dose coefficients for environmental radioiodine intake based on newly developed age-specific biokinetic models. However, the biokinetics of iodine has been reported to be strongly dependent on the dietary intake of stable iodine; for example, the thyroidal uptake of iodine may be substantially lower in iodine-rich regions than in iodine-deficient regions. There-fore, this study attempted to establish a system of age-specific thyroid dose estimation for South Koreans, whose daily iodine intakes are significantly higher than that of the world population. Materials and Methods: Korean age-specific biokinetic parameters and thyroid masses were derived based on the previously developed Korean adult model and the Korean anatomical reference data for adults, respectively. This study complied with the principles used in the development of age-specific biokinetic models for world population and used the ratios of baseline values for each age group relative to the value for adults to derive age-specific values. Results and Discussion: Biokinetic model predictions based on the Korean age-specific parameters showed significant differences in iodine behaviors in the body compared to those predicted using the model for the world population. In particular, the Korean age-specific thyroid dose coefficients for 129 I and 131 I were considerably lower than those calculated for the world population (25%–76% of the values for the world population). Conclusion: These differences stress the need for Korean-specific internal dose assessments for infants and children, which can be achieved by using the data calculated in this study.
{"title":"Age-Specific Thyroid Internal Dose Estimation for Koreans","authors":"Tae-Eun Kwon, Seokwon Yoon, Wi-Ho Ha, Yoonsun Chung, Y. Jin","doi":"10.14407/jrpr.2021.00066","DOIUrl":"https://doi.org/10.14407/jrpr.2021.00066","url":null,"abstract":"Background: The International Commission on Radiological Protection is preparing to pro-vide reference dose coefficients for environmental radioiodine intake based on newly developed age-specific biokinetic models. However, the biokinetics of iodine has been reported to be strongly dependent on the dietary intake of stable iodine; for example, the thyroidal uptake of iodine may be substantially lower in iodine-rich regions than in iodine-deficient regions. There-fore, this study attempted to establish a system of age-specific thyroid dose estimation for South Koreans, whose daily iodine intakes are significantly higher than that of the world population. Materials and Methods: Korean age-specific biokinetic parameters and thyroid masses were derived based on the previously developed Korean adult model and the Korean anatomical reference data for adults, respectively. This study complied with the principles used in the development of age-specific biokinetic models for world population and used the ratios of baseline values for each age group relative to the value for adults to derive age-specific values. Results and Discussion: Biokinetic model predictions based on the Korean age-specific parameters showed significant differences in iodine behaviors in the body compared to those predicted using the model for the world population. In particular, the Korean age-specific thyroid dose coefficients for 129 I and 131 I were considerably lower than those calculated for the world population (25%–76% of the values for the world population). Conclusion: These differences stress the need for Korean-specific internal dose assessments for infants and children, which can be achieved by using the data calculated in this study.","PeriodicalId":36088,"journal":{"name":"Journal of Radiation Protection and Research","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2021-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89672372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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