|
|
Evaluation of the gamma-ray spectrum transmitted upon alteration in scintillator shading
Zbožínek, Tadeáš ; Jelínek, Michal ; Mikel, Břetislav
This paper deals with determining the properties of optical fibres required for transmitting energy spectra in ionising radiation measurements by scintillation. Specifically, optical fibres that provide the communication link between the scintillator and the photosensitive electronic devices. The primary objective is focused on the basic diameter and numerical aperture values required for efficient transmission of energy spectra. An iris mechanism gradually shaded the scintillator crystal, simulating the optical fibre diameter. The results can be used to calculate the numerical aperture to achieve this goal. This way, we can establish basic properties for further energy spectra measurements with optical fibres.
|
|
|
Proportional counter measurement system
Horna, Aleš ; Matěj, Zdeněk (referee) ; Kubíček, Michal (advisor)
The thesis deals with gas-filled proportional counters intended for the detection of presence of ionising radiation and its properties. Proportional counters make it possible to find out about the type and energy of ionising particles. The thesis analyses the theory regarding the character of ionising radiation and its detection, describes the measuring apparatus used and the possibilities of verification of counters function. It also deals with the character of signals from the detectors and its imitation. It documents the measurements carried out with various sources of ionising radiation and interpretation of the acquired data, suggests and describes possible improvements of the measuring apparatus.
|
|
|
Communication about radiation risks in civil protection from the perspective of ethics
DVOŘÁKOVÁ, Žaneta
The present thesis examines the ethical perspective of communicating radiation risks in civil protection. The objective was to determine to what extent and how ethical principles are considered in communicating radiation risks in civil protection. The theoretical part of the thesis apply information to ionising radiation, radiation risks, and the principles and means of radiation protection. It also describes the communication and ethical principles and practices in communication and radiation protection are described therein. The scope of this part of the thesis includes the protection of the population in emergencies. The practical part of the thesis focuses on public awareness of radiation risks and whether ethical principles are used in communicating them. A quantitative research method, namely a questionnaire survey involving 142 respondents, was used to analyse the goals and objectives of the practical part of the thesis. The questionnaire was distributed electronically to residents living near a nuclear facility or in the emergency plan zone of a nuclear power plant. The research results are presented as graphs. The evaluation of the questionnaire results has revealed that the level of public awareness of radiation risks is acceptable. The results also indicate that ethical principles are applied in the communication process. However, some of the respondents found the questions on ethics difficult, possibly due to their lack of knowledge in this area. Nevertheless, they were helpful for the research.
|
|
|
Radiation exposure of persons working in the risk of ioniing radiation in the University Hospital in Pilsen
ULČOVÁ, Radka
The diploma thesis on "Radiation exposure of persons working at risk of ionising radiation at the Pilsen University Hospital" is divided into two parts. The first analyses personal effective doses of the employees of the Pilsen University Hospital in 20092013, and the second focuses on measurements of secondary radiation created after the activation of collimator systems of linear accelerators. The introduction of the theoretical part discusses the history of radiology, followed by a summary of information on the sources of ionising radiation, its characteristics, properties, methods of interaction with the environment and biological effects on organisms. The chapter on radiation protection focuses on basic legislative regulations relevant to the topic. In the Czech Republic, radiation protection of people working with sources of ionising radiation is mostly based on Act No. 18/1997 Coll., on peaceful uses of nuclear energy, and Regulation of the State Office for Nuclear Safety No. 307/2002 Coll., on radiation protection. The thesis also lists dose limits and basic information about personal dosimetry, and the theoretical section is concluded with information on the methods of protecting personnel and on provided healthcare. The thesis uses as its sources primary literature, internet links, current legislation and data from the database of the State Office for Nuclear Safety on records from personal dosimeters in the analysed period. The thesis had two objectives. The first was to compare levels of exposure at the Pilsen University Hospital. The analysis involved 579 persons in total; after arranging the data into tables and dividing employees into groups by the type of tasks they perform and their job, it was possible to compare median value indicators, confirming the hypothesis that persons carrying out intervention tasks are exposed to more ionising radiation. In order to compare the development of doses over time, a double-selection t-test was performed on data from 2009 and 2013, confirming the effectiveness of anti-radiation measures adopted at the University Hospital and a reduction in the exposure of employees in this period. The second objective was to confirm or deny the hypothesis that secondary radiation created by collimator systems, while measurable, is not sufficiently large to be detected by personal dosimeters. In order to achieve this objective, measurements were carried out at the Oncology and Radiology Clinic of the Pilsen University Hospital. The first measurements tried to determine the relationship between dose and time at various levels of energy, the second compared the relationship between dose and distance from the collimator plane and the third monitored the number of exposures until the collimator plates are saturated and dose is no longer increased. All results were arranged in tables and projected in charts. The results of the research confirmed the hypothesis that secondary radiation created during the use of high-energy equipment is just below the detection limits of personal dosimeters. For this reason, it is recommended to frequently rotate personnel working with the equipment.
|
|
|
Analysis of radiation control in the storage of spent nuclear fuel at NPP Temelín
PAPAN, Juraj
Problems of dealing with radioactive materials, especially burnt out nuclear fuel, are a delicate and discussed topic in the Czech Republic and other advanced countries nowadays. In this work, the realization of radiation control of warehouse of burnt-out atomic fuel of nuclear power plant Temelín is analysed. Step by step there are stored packaging files filled with burnt-out fuel which is produced by the running of atomic reactors. In the introductory chapters individual packaging files are described. The shielding of stored burnt-out nuclear fuel and prevention of release of radionuclides beyond the protective casing of packaging files depend on their quality. Further the lo-cality of nuclear plant Temelín, where the warehouse of burnt-out nuclear fuel is placed including manipulations which are carried out with the packaging file, is described. The emphasis is placed on monitoring technological parameters during the storage of pack-aging files. The target of this work is to analyse the radiation control of warehouse of burnt-out nuclear fuel, precautions of radiation protection valid for this object and con-sider the possibility of optimalization of used measuring devices, suggest the adjustment of the way of carried out monitoring. For meeting the goals of this works it was neces-sary to carry out monitoring the current radiation situation in the storage boat which is partly filled with packaging spaces when according to the following calculations I ap-proached to the prediction of the level of radiation situation during the maximum filled storage boat. These calculations are at the same time the background for the proposal of adjustment of regime precautions in this object with the aim to optimise the professional radiation. One of the basic strategic targets of the operator of nuclear plant Temelín, company ČEZ a.s., is to ensure a safe operation of the biggest Czech nuclear plant, one of the basic conditions for meeting this target is to ensure the radiation control and pro-tection in the required quality. The results, which are the output of this work, will be given to the department Operation of radiation protection for other practical usage, pos-sible adjustment of a current operation documentation which solves the radiation control of the storage of burnt-out nuclear fuel.
|
|
|
Inspesting the sensitivity and resolution of the CT-part of the Infinia-Hawkeye
FILÁSKOVÁ, Lucie
The medical discipline of nuclear medicine is characterised by the constant development and perfection of the appliances used and thus, also higher diagnostic yield. The most frequently used equipment currently includes hybrid appliances enabling image fusion, e.g. SPECT/CT. The result is a recording combining anatomical and functional information allowing for more accurate localisation of the lesion and better spatial orientation. Equipment in nuclear medicine is subject to inspection under the regulation of the State Office for Nuclear Safety No 307/2002 Coll. On radiation protection and as amended under Regulation No 499/2005 Coll. When inspecting the characteristics of an appliance, procedures specified by the manufacturer are met, and each workplace performing nuclear medicine must follow a sophisticated system of quality control stipulating the individual tests and duration of the cycle when they shall be performed. My work consisted of performing quality tests on the CT-part of the Infinia-Hawkeye system. The testing was performed once every three weeks over a period of seven months at the Department of Nuclear Medicine in České Budějovice hospital. The results of individual readings were recorded in overview charts and compared with the parameters provided by the manufacturer. The performance of the comparison confirmed the defined goals, all the recorded values agreed with the limits set by the manufacturer. These values were never exceeded during the entire testing period. No short-term changes of parameters were recorded. The bachelor?s thesis can be used as an overview of quality tests of the CT-part of the Infinia-Hawkeye system and can also serve as instructions for performing these inspections at all workplaces that are equipped with the Infinia-Hawkeye hybrid system.
|
|
|
Problems of secondary tumours after the irradiation for the carcinoma prostate
ŽÍŽALOVÁ, Hana
Radiotherapy is an important branch of the complex oncology care. The treatment of tumours derives benefit from the effect of an interaction of ionizing radiation with tumour cells. The aim of radiotherapy is to deliver the sufficient dose to exceed over the threshold for deterministic effect for tumour cells to eliminate them. However at the same time the neighbouring critical organs and tissue should be protected i.e. they should be exposed by the inconsiderable dose. In the critical organs and other irradiated tissue there is possible to induce a malign proliferation - so-called secondary cancers or secondary stochastic effect. The stochastic effect has no - on the contrary to deterministic effect {--} any threshold and it has usually long period of latency. In the diploma work there are studied and discussed the secondary stochastic effects induced in the critical organs (rectum und urinary bladder) during the radiotherapy of prostate carcinoma.
|
|
|
Monitoring the personnel radiation load in percutaneous interventions
SKÁCELOVÁ, Lada
The discovery of ionising radiation at the turn of the nineteenth and twentieth centuries was a landmark for medicine: the methods based on the principle and effects of ionising radiation are used even in the present medicine to a considerable extent. As early as in the very beginnings, adverse affects of ionising radiation were observed, and from this early period the first references to the need of radiation protection date. The fields of medicine dealing with the application of ionising radiation, whether in the diagnosis or in the therapy of diseases, went through an extensive development in their over hundred-year history. It was in the technical sphere in particular where the most important progress was accomplished, thanks to the ever more advanced instrumentation put on the market, meeting the strict criteria of radiation protection. On the one hand, a large group of diagnostic and therapeutic procedures was replaced by new methods (based on ultrasound and magnetic resonance) that are not based on ionising radiation, and thus the patient or the attending personnel are not exposed to the harmful effects of the radiation. On the other hand, the interventional radiology has attained an unprecedented expansion. With the development of new interventional methods and procedures, the number and duration of interventions has been growing. The radiation load to which the intervening personnel are exposed has thus been rising despite the state-of-the-art instrumentation. The theoretical part of the dissertation describes the origin and types of the ionising radiation, its properties and interactions with the environment; a proportional part has been devoted to the biological effects of the radiation. The prime attention has been concentrated on radiation protection, its objectives, principles and methods of radiation protection. An overview of the current legislation and list of requirements on the radiation monitoring has been elaborated. In the chapter on personal dosimetry, the fundamental relations and quantities used in the radiation dosimetry have been described, as well as the types of personal dosimeters and protective equipment. In the practical part, the radiation load of the personnel attending percutaneous interventions in the department of interventional radiology of the Clinic of Radiology of the Teaching Hospital Olomouc was measured. Personal electronic radiation dosimeters Rados, type RAD 60S, were used. All the data obtained were processed using statistical methods, and, on the basis of the results thus obtained, the effectiveness of protection was determined, and the importance of the observation of the principles of radiation hygiene was evaluated. The presumed use of the results of this work in practice is in the optimisation of procedures and measures leading to the maximum possible reduction of the radiation load in percutaneous interventions, and to the education and guidance of personnel towards consequential compliance with all principles of the radiation hygiene.
|
guest ::
