Pub Date : 2021-07-15DOI: 10.3769/RADIOISOTOPES.70.271
M. A. Choghadi, Mizuki Kitajima, M. Uenomachi, K. Shimazoe, H. Takahashi
We have proposed a new concept of time/position correlation type tomographic method based on a directionality-sensitive gamma camera, which can identify incident γ-ray direction. This method utilizes the correlation between two γ-ray photons and provides the radioactivity concentration in the body with a high resolution and a high signal-to-noise ratio. 111 In is known as a cascade γ-ray emitting nuclide. Besides 111 In, we have explored new candidates and found some other nuclides with different lifetimes. A focused lead col limator was designed and coupled to a pixelated detector array for this new coincidence imaging modality. The method shows a significant background rejection and an improved spatial resolution in comparison with the single-photon analysis.
{"title":"Collimator-based Coincidence Imaging for Double Photon Emitting Nuclides","authors":"M. A. Choghadi, Mizuki Kitajima, M. Uenomachi, K. Shimazoe, H. Takahashi","doi":"10.3769/RADIOISOTOPES.70.271","DOIUrl":"https://doi.org/10.3769/RADIOISOTOPES.70.271","url":null,"abstract":"We have proposed a new concept of time/position correlation type tomographic method based on a directionality-sensitive gamma camera, which can identify incident γ-ray direction. This method utilizes the correlation between two γ-ray photons and provides the radioactivity concentration in the body with a high resolution and a high signal-to-noise ratio. 111 In is known as a cascade γ-ray emitting nuclide. Besides 111 In, we have explored new candidates and found some other nuclides with different lifetimes. A focused lead col limator was designed and coupled to a pixelated detector array for this new coincidence imaging modality. The method shows a significant background rejection and an improved spatial resolution in comparison with the single-photon analysis.","PeriodicalId":20809,"journal":{"name":"Radioisotopes","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81025714","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 : 2021-07-15DOI: 10.3769/radioisotopes.70.251
{"title":"Survey Report of RI Production and Application in 2019","authors":"","doi":"10.3769/radioisotopes.70.251","DOIUrl":"https://doi.org/10.3769/radioisotopes.70.251","url":null,"abstract":"","PeriodicalId":20809,"journal":{"name":"Radioisotopes","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82598920","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 : 2021-07-15DOI: 10.3769/RADIOISOTOPES.70.291
K. Koba, K. Kinoshita, Yuji Onishi, K. Fukushima, K. Osaka, N. Matsuo, Kazuho Funakawa, Yugo Seko, Ayano Medo, R. Hirasawa, N. Ogawa, F. Hyodo, C. Yoshimizu
{"title":"Carbon and Nitrogen Isotope Analysis on Small Samples Using a Near-conventional EA-IRMS System","authors":"K. Koba, K. Kinoshita, Yuji Onishi, K. Fukushima, K. Osaka, N. Matsuo, Kazuho Funakawa, Yugo Seko, Ayano Medo, R. Hirasawa, N. Ogawa, F. Hyodo, C. Yoshimizu","doi":"10.3769/RADIOISOTOPES.70.291","DOIUrl":"https://doi.org/10.3769/RADIOISOTOPES.70.291","url":null,"abstract":"","PeriodicalId":20809,"journal":{"name":"Radioisotopes","volume":"139 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78130349","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 : 2021-07-15DOI: 10.3769/RADIOISOTOPES.70.301
K. Katoh
{"title":"Analysis of Difficulties with Water Containing Tritium and Considerations on Remedy","authors":"K. Katoh","doi":"10.3769/RADIOISOTOPES.70.301","DOIUrl":"https://doi.org/10.3769/RADIOISOTOPES.70.301","url":null,"abstract":"","PeriodicalId":20809,"journal":{"name":"Radioisotopes","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79470538","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 : 2021-05-15DOI: 10.3769/RADIOISOTOPES.70.239
C. Mori
{"title":"Imaging Plate, Its Glory and Transition","authors":"C. Mori","doi":"10.3769/RADIOISOTOPES.70.239","DOIUrl":"https://doi.org/10.3769/RADIOISOTOPES.70.239","url":null,"abstract":"","PeriodicalId":20809,"journal":{"name":"Radioisotopes","volume":"15 1","pages":"239-249"},"PeriodicalIF":0.0,"publicationDate":"2021-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87179350","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 : 2021-05-15DOI: 10.3769/RADIOISOTOPES.70.219
Fengquan Shi, R. Taniguchi, T. Kojima
{"title":"Development of Semiconductor Preamplifier with Radiation Hardness","authors":"Fengquan Shi, R. Taniguchi, T. Kojima","doi":"10.3769/RADIOISOTOPES.70.219","DOIUrl":"https://doi.org/10.3769/RADIOISOTOPES.70.219","url":null,"abstract":"","PeriodicalId":20809,"journal":{"name":"Radioisotopes","volume":"10 1","pages":"219-225"},"PeriodicalIF":0.0,"publicationDate":"2021-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88912298","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 : 2021-05-15DOI: 10.3769/RADIOISOTOPES.70.209
Nattawipa Suwannasaeng, T. Kakizaki, 柿崎竹彦, Seiichi Wada, 和田成一, M. Natsuhori, 夏堀雅宏
External exposure of veterinary staffs and owners in veterinary nuclear medicine was estimated by monitoring the surface dose rate (SDR) and ambient dose rate (ADR) from the feline renal patient (n=20) and controls (normal cats, n=8) during and after renal scintigraphy with 99mTc-mercaptoacetyl triglycine (MAG3, dose 93-141 MBq/head). The highest SDR was at the ventral side of abdomen and its SDR-time course followed within the degradation curve with physical half-life (6.01 h) ADR demonstrated significant decrease up to about 100-fold by keeping distance from the patient at 100 cm. All cats showed acceptable SDR which was less than 115 μSv/h in 24 h post injection, where cumulative SDR till infinity was less than 1 mSv (=dose limit to the public). Urination had a conspicuous effect on SDR at 24 h (0.38–9.6 μSv/h) and all urinated cat showed less than 1/10 of the limit of the yearly external public exposure. These results satisfied current legislation in Japan, while the 24 h post-dose regulation was considered over-regulated in the case of sufficiently lower maximum SDR. From the perspective of overburdening animals, their owners, and veterinary clinics, it was considered desirable to determine criteria based on the maximum SDR for each patient.
{"title":"External Exposure of Veterinary Staffs and Pet Owners from Feline 99mTc-MAG3 Renal Scintigraphy","authors":"Nattawipa Suwannasaeng, T. Kakizaki, 柿崎竹彦, Seiichi Wada, 和田成一, M. Natsuhori, 夏堀雅宏","doi":"10.3769/RADIOISOTOPES.70.209","DOIUrl":"https://doi.org/10.3769/RADIOISOTOPES.70.209","url":null,"abstract":"External exposure of veterinary staffs and owners in veterinary nuclear medicine was estimated by monitoring the surface dose rate (SDR) and ambient dose rate (ADR) from the feline renal patient (n=20) and controls (normal cats, n=8) during and after renal scintigraphy with 99mTc-mercaptoacetyl triglycine (MAG3, dose 93-141 MBq/head). The highest SDR was at the ventral side of abdomen and its SDR-time course followed within the degradation curve with physical half-life (6.01 h) ADR demonstrated significant decrease up to about 100-fold by keeping distance from the patient at 100 cm. All cats showed acceptable SDR which was less than 115 μSv/h in 24 h post injection, where cumulative SDR till infinity was less than 1 mSv (=dose limit to the public). Urination had a conspicuous effect on SDR at 24 h (0.38–9.6 μSv/h) and all urinated cat showed less than 1/10 of the limit of the yearly external public exposure. These results satisfied current legislation in Japan, while the 24 h post-dose regulation was considered over-regulated in the case of sufficiently lower maximum SDR. From the perspective of overburdening animals, their owners, and veterinary clinics, it was considered desirable to determine criteria based on the maximum SDR for each patient.","PeriodicalId":20809,"journal":{"name":"Radioisotopes","volume":"151 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79530421","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 : 2021-05-15DOI: 10.3769/RADIOISOTOPES.70.227
Kenta Hagiwara, Kotaro Ochi, Yuya Koike
Behavior of radioactive caesium, derived from Fukushima Dai-ichi Nuclear Power Plant Accident, in river water and sediment investigated during 2012–2016. Concentrations of radioactive caesium in river water and sediment were decreased with time exponentially. The residence half-life of radioactive caesium in the river water and sediment were 0.788–1.50 year for 134Cs, 1.22–2.17 year for 137Cs. Any decrease in radioactive caesium concentration in the Tama river is because of weathering effect than radioactive decay. Concentrations of suspended radioactive caesium temporarily increased when sediments were resuspended due to rain. On the other hand, dissolved radioactive caesium is not easily impacted by this factor. Radioactive caesium concentration in sediments was considerably higher than that in river water. It indicated that much of the radioactive caesium in the Tama river existed in the sediments. Sequential extraction, elemental and crystal phase analysis were performed on the sediments and examined the chemical state of radioactive caesium as well as the adsorption mechanism. Radioactive caesium in sediment was present in a stable chemical form, and there is possibility that radioactive caesium was incorporated in biotite.
2012-2016年福岛第一核电站事故放射性铯在河水和沉积物中的行为研究河水和沉积物中放射性铯的浓度随时间呈指数递减。放射性铯在河水和沉积物中的停留半衰期为:134Cs为0.788 ~ 1.50 a, 137Cs为1.22 ~ 2.17 a。多摩河放射性铯浓度的任何下降都是由于风化作用而不是放射性衰变。当沉积物因降雨而重新悬浮时，悬浮放射性铯的浓度会暂时升高。另一方面，溶解的放射性铯不容易受到这个因素的影响。沉积物中的放射性铯浓度明显高于河水。这表明多摩河中的放射性铯大部分存在于沉积物中。对沉积物进行了序贯萃取、元素和晶相分析，考察了放射性铯的化学状态及其吸附机理。沉积物中的放射性铯以稳定的化学形式存在，并且有可能放射性铯被并入黑云母中。
{"title":"Fixed Point Observations and Characterization of Radioactive Caesium in Tama River","authors":"Kenta Hagiwara, Kotaro Ochi, Yuya Koike","doi":"10.3769/RADIOISOTOPES.70.227","DOIUrl":"https://doi.org/10.3769/RADIOISOTOPES.70.227","url":null,"abstract":"Behavior of radioactive caesium, derived from Fukushima Dai-ichi Nuclear Power Plant Accident, in river water and sediment investigated during 2012–2016. Concentrations of radioactive caesium in river water and sediment were decreased with time exponentially. The residence half-life of radioactive caesium in the river water and sediment were 0.788–1.50 year for 134Cs, 1.22–2.17 year for 137Cs. Any decrease in radioactive caesium concentration in the Tama river is because of weathering effect than radioactive decay. Concentrations of suspended radioactive caesium temporarily increased when sediments were resuspended due to rain. On the other hand, dissolved radioactive caesium is not easily impacted by this factor. Radioactive caesium concentration in sediments was considerably higher than that in river water. It indicated that much of the radioactive caesium in the Tama river existed in the sediments. Sequential extraction, elemental and crystal phase analysis were performed on the sediments and examined the chemical state of radioactive caesium as well as the adsorption mechanism. Radioactive caesium in sediment was present in a stable chemical form, and there is possibility that radioactive caesium was incorporated in biotite.","PeriodicalId":20809,"journal":{"name":"Radioisotopes","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74992035","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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