Pub Date : 2019-01-09DOI: 10.5772/INTECHOPEN.82726
K. Polaczek-Grelik, A. Kawa-Iwanicka, M. Rygielski, Ł. Michalecki
Radiotherapy using high-energy photon beams (10–20 MV) is accompanied by the production of secondary neutron radiation via ( γ /X,n) reactions. These interactions as well as subsequent neutron capture are the source of induced gamma radioactivity. When studied with standard range of spectrometric systems, only decay gamma radiation is usually registered, whereas a significant part of radiation— prompt gammas—is omitted, what might result in a significant underestimation of occupational risk for therapists in the vicinity of the door to the treatment room during therapeutic beam emission. Presented study has shown the main components of gamma radiation field in this localization investigated with the use of high-purity germanium spectrometry. Among them, prompt gamma radiation in light elements of concrete and in metal construction of the door, as well as 477.6 and 2224.6 keV photons emitted by neutron absorbing layers, contributes the most. Effective dose values depend on thickness of the door as well as on neutron production by particular linac and are within the range of 1.8–56.2 μ Sv/h. Standard environmental radiometry could underestimate these values by about 60% due to low efficiency for high-energy photon counting.
{"title":"Gamma Radiation in the Vicinity of the Entrance to Linac Radiotherapy Room","authors":"K. Polaczek-Grelik, A. Kawa-Iwanicka, M. Rygielski, Ł. Michalecki","doi":"10.5772/INTECHOPEN.82726","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.82726","url":null,"abstract":"Radiotherapy using high-energy photon beams (10–20 MV) is accompanied by the production of secondary neutron radiation via ( γ /X,n) reactions. These interactions as well as subsequent neutron capture are the source of induced gamma radioactivity. When studied with standard range of spectrometric systems, only decay gamma radiation is usually registered, whereas a significant part of radiation— prompt gammas—is omitted, what might result in a significant underestimation of occupational risk for therapists in the vicinity of the door to the treatment room during therapeutic beam emission. Presented study has shown the main components of gamma radiation field in this localization investigated with the use of high-purity germanium spectrometry. Among them, prompt gamma radiation in light elements of concrete and in metal construction of the door, as well as 477.6 and 2224.6 keV photons emitted by neutron absorbing layers, contributes the most. Effective dose values depend on thickness of the door as well as on neutron production by particular linac and are within the range of 1.8–56.2 μ Sv/h. Standard environmental radiometry could underestimate these values by about 60% due to low efficiency for high-energy photon counting.","PeriodicalId":159488,"journal":{"name":"Use of Gamma Radiation Techniques in Peaceful Applications","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128592786","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 : 2019-01-03DOI: 10.5772/INTECHOPEN.82752
Hai Lin, Chengpu Liu, Chen Wang
Production of artificial gamma-ray source usually is a conception belonging to the category of experimental nuclear physics. Nuclear physicists achieve this goal through utilizing/manipulating nucleons, such as proton and neutron. Low-energy electrons are often taken as “ by-products ” when preparing these nucleons by ion-izing atoms, molecules and solids, and high-energy electrons or β rays are taken as “ wastage ” generated in nuclear reaction. Utilization of those “ by-products ” has not won sufficient attention from the nuclear physics community. In this chapter, we point out a potential, valuable utilization of those “ by-products. ” Based on a universal principle of achieving powerful mono-color radiation source, we propose how to set up an efficient powerful electron-based gamma-ray source through available solid-state components/elements. Larger charge-to-mass ratio of an electron warrants the advantage of electron-based gamma-ray source over its nucleon-based counterpart. Our technique offers a more efficient way of manipulating nuclear matter through its characteristic EM stimulus. It can warrant sufficient dose/brightness/intensity and hence an efficient manipulation of nuclear matter. Especially, the manipulation of a nucleus is not at the cost of destroying many nuclei to generate a desired tool, that is, gamma ray with sufficient intensity, for achieving this goal. This fundamentally warrants a practical manipulation of more nuclei at desirable number.
{"title":"Electron Oscillation-Based Mono-Color Gamma-Ray Source","authors":"Hai Lin, Chengpu Liu, Chen Wang","doi":"10.5772/INTECHOPEN.82752","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.82752","url":null,"abstract":"Production of artificial gamma-ray source usually is a conception belonging to the category of experimental nuclear physics. Nuclear physicists achieve this goal through utilizing/manipulating nucleons, such as proton and neutron. Low-energy electrons are often taken as “ by-products ” when preparing these nucleons by ion-izing atoms, molecules and solids, and high-energy electrons or β rays are taken as “ wastage ” generated in nuclear reaction. Utilization of those “ by-products ” has not won sufficient attention from the nuclear physics community. In this chapter, we point out a potential, valuable utilization of those “ by-products. ” Based on a universal principle of achieving powerful mono-color radiation source, we propose how to set up an efficient powerful electron-based gamma-ray source through available solid-state components/elements. Larger charge-to-mass ratio of an electron warrants the advantage of electron-based gamma-ray source over its nucleon-based counterpart. Our technique offers a more efficient way of manipulating nuclear matter through its characteristic EM stimulus. It can warrant sufficient dose/brightness/intensity and hence an efficient manipulation of nuclear matter. Especially, the manipulation of a nucleus is not at the cost of destroying many nuclei to generate a desired tool, that is, gamma ray with sufficient intensity, for achieving this goal. This fundamentally warrants a practical manipulation of more nuclei at desirable number.","PeriodicalId":159488,"journal":{"name":"Use of Gamma Radiation Techniques in Peaceful Applications","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132043438","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 : 2018-12-31DOI: 10.5772/INTECHOPEN.83031
B. Persson
In 1960 Caesium-137 activity from atmospheric nuclear weapons test was dis-covered in measurements at the whole body gamma-ray counting laboratory inLund. This event initiated measurements of the Swedish Sami population, and inproducts from reindeer that bite lichens in the Swedish mountains. A semi-portable whole-body counter designed with a detection limit for 137 Cs at high radiation background areas which was good enough for measuring people with high body concentration of 137 Cs. The 137 Cs activity concentration in Sami people increased during 1963 -1965 from 300 to 600 Bq/kg body weight. Some individual males had values above 1000 Bq/kg. The catastrophic nuclear accident on the 25 – 26 April 1986 at the Chernobyl Nuclear Power Plant caused a massive release of fission- and neutron-activation products to the atmosphere. Already the following day the atmospheric plume of released radioactivity reached Sweden and was deposited over the central part of Sweden also in Sami populated reindeer raising districts. During 1991 and 1992 whole-body content of 137 Cs was measured in the Sami population of northern Sweden and similar levels were found as during 1963 –1965. These levels are about twice those estimated in people living in the Chernobyl contaminated area. (Less)
{"title":"Gamma-Ray Emitting Radionuclides in People Living in Northern Sub Arctic Regions","authors":"B. Persson","doi":"10.5772/INTECHOPEN.83031","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.83031","url":null,"abstract":"In 1960 Caesium-137 activity from atmospheric nuclear weapons test was dis-covered in measurements at the whole body gamma-ray counting laboratory inLund. This event initiated measurements of the Swedish Sami population, and inproducts from reindeer that bite lichens in the Swedish mountains. A semi-portable whole-body counter designed with a detection limit for 137 Cs at high radiation background areas which was good enough for measuring people with high body concentration of 137 Cs. The 137 Cs activity concentration in Sami people increased during 1963 -1965 from 300 to 600 Bq/kg body weight. Some individual males had values above 1000 Bq/kg. The catastrophic nuclear accident on the 25 – 26 April 1986 at the Chernobyl Nuclear Power Plant caused a massive release of fission- and neutron-activation products to the atmosphere. Already the following day the atmospheric plume of released radioactivity reached Sweden and was deposited over the central part of Sweden also in Sami populated reindeer raising districts. During 1991 and 1992 whole-body content of 137 Cs was measured in the Sami population of northern Sweden and similar levels were found as during 1963 –1965. These levels are about twice those estimated in people living in the Chernobyl contaminated area. (Less)","PeriodicalId":159488,"journal":{"name":"Use of Gamma Radiation Techniques in Peaceful Applications","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115594384","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 : 2018-11-27DOI: 10.5772/INTECHOPEN.81964
S. Mirmajlessi, H. Mostafavi, E. Loit, N. Najdabbasi, M. Mänd
Biological control is a potential nonchemical method to manage plant pathogens by beneficial microorganisms. To improve antagonistic potential of biocontrol agents, mutation by radiations, chemicals, and genetic manipulations has been used. Genetic techniques and ionizing radiation containing direct or indirect emissions play the greatest role for selection of useful microorganisms to enhance the efficiency of biological systems. Indeed, genetic engineering has a main role in increasing antimicrobial metabolites, host colonization ability, and endurance in micro-ecosystem. Genetic improvement can be achieved by protoplast fusion, genetic modification (GM), and chemical (genotoxic agents) and physical mutations. However, ultraviolet light and ionizing radiations can induce modifications in the genome of an organism. Irradiation, particularly gamma rays, is also applied for controlling postharvest diseases. Indeed, irradiation cannot completely eliminate pathogens, but it might result in cell injury and directly damage the chromosomal DNA of a living cell. This technology has been used for many reasons including disinfestation of foods, reducing foodborne pathogens, and extending shelf life many fruits, vegetables, and nuts. In the current review, we discuss advances in the radiation and molecular genetic techniques with the aim to improve antagonistic potential of microorganisms as it is applied to the suppression of plant pathogens.
{"title":"Application of Radiation and Genetic Engineering Techniques to Improve Biocontrol Agent Performance: A Short Review","authors":"S. Mirmajlessi, H. Mostafavi, E. Loit, N. Najdabbasi, M. Mänd","doi":"10.5772/INTECHOPEN.81964","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.81964","url":null,"abstract":"Biological control is a potential nonchemical method to manage plant pathogens by beneficial microorganisms. To improve antagonistic potential of biocontrol agents, mutation by radiations, chemicals, and genetic manipulations has been used. Genetic techniques and ionizing radiation containing direct or indirect emissions play the greatest role for selection of useful microorganisms to enhance the efficiency of biological systems. Indeed, genetic engineering has a main role in increasing antimicrobial metabolites, host colonization ability, and endurance in micro-ecosystem. Genetic improvement can be achieved by protoplast fusion, genetic modification (GM), and chemical (genotoxic agents) and physical mutations. However, ultraviolet light and ionizing radiations can induce modifications in the genome of an organism. Irradiation, particularly gamma rays, is also applied for controlling postharvest diseases. Indeed, irradiation cannot completely eliminate pathogens, but it might result in cell injury and directly damage the chromosomal DNA of a living cell. This technology has been used for many reasons including disinfestation of foods, reducing foodborne pathogens, and extending shelf life many fruits, vegetables, and nuts. In the current review, we discuss advances in the radiation and molecular genetic techniques with the aim to improve antagonistic potential of microorganisms as it is applied to the suppression of plant pathogens.","PeriodicalId":159488,"journal":{"name":"Use of Gamma Radiation Techniques in Peaceful Applications","volume":"9 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120816998","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：