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Sample preparation and their measurement by EDS methods
Kostelník, Tomáš ; Jaššo, Kamil (referee) ; Čudek, Pavel (advisor)
This bachelor´s thesis is focused on preparation and analysis of samples by energy dispersive spectroscopy using scanning electron microscopy. In the theoretical the main differences between environmental scanning electron microscopy and scanning electron microscopy are described. There is also a description of basic knowledge regarding energy dispersive spectroscopy. The generation and detection of signals arising from the interaction of a beam of primary electrons with a sample is also explained, with emphasis on the description, generation and distribution of these signals. The experimental part is focused on sample preparation and analysis.
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Determination of the chemical composition of a brass sample by X-ray fluorescence method
Tomanová, Michaela ; Čudek, Pavel (referee) ; Vaněk, Jiří (advisor)
The fluorescence spectroscopy method is used to distinguish components in gas, liquid, or solid samples. The study is based on the parameters of secondary radiation, which is emitted by each element and allows them to be identified. The distinction between each radiation is analogous to a fingerprint. Apart from quantitative and qualitative analyses, the method can be used to determine the thickness of metal layers and alloys. Laboratory analysis has a broader range of application than portable devices, which are also available. In the laboratory, two methods of measurement are available: wavelength dispersive fluorescence spectroscopy – WDXRF and energo dispersive fluorescence spectroscopy – EDXRF. A brass sample with lead additive was analyzed using EDXRF in the practical part of this diploma thesis. An X-ray apparatus from the Leybold company was employed for the analysis, which will be used for education of lower grades at the university. A measurement station and a laboratory assignment were developed as part of the thesis, the aim of which will be to determine the chemical composition of a brass sample using the X-ray fluorescence method.
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Module for detection of ionizing radiation
Matějka, Tomáš ; Džbánek, Lukáš (referee) ; Kubíček, Michal (advisor)
This thesis deals with design of detector of ionizing X-ray radiation. Conventional PIN photodiodes are used for construction of the detector. The thesis describes issue of using PIN photodiodes for X-ray and gamma radiation detection. Transimpedance amplifier is designed with two diferent modes of detection. Both amplifier variants are compared and their suitability for specific applications is discussed. The thesis describes principle of converting analog signals to digital and describes concept of bus for multiple detectors connection to central unit. Options for paralel data processing are discused in last part of thesis. The detector is implemented and measured values are compared with simulations.
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Noise reduction in high resolution computed tomography data
Tkadlecová, Markéta ; Chmelík,, Jiří (referee) ; Zikmund, Tomáš (advisor)
Vzhledem ke komplexnosti procesu akvizice dat výpočetní tomografie (CT) je šum v rentgenových snímcích nevyhnutelný a může vést ke zkreslení získané informace. Proto by měl být co nejvíce potlačen. Dosud se výzkum zaměřoval především na redukci šumu v CT datech u lékařských CT s nízkými dávkami, zatímco o šumu a jeho potlačení v CT datech s vysokým rozlišením je známo jen málo. Tato redukce může probíhat v oblasti rentgenových snímků, v průběhu tomografické rekonstrukce nebo v oblasti tomografických řezů. Tato práce se zabývá především redukcí šumu v rentgenových snímcích a tomografických řezech. Prvním krokem k nalezení komplexní metodiky je určení rozdělení a matematického modelu šumu přítomného v rentgenových snímcích. Tento model byl určen pomocí snímků bez přítomného vzorku, které byly pořízeny s různými expozičními časy. Pomocí stanoveného modelu byl simulován šum ve fantomovém datasetu. Vybrané algoritmy byly testovány na projekčních snímcích a tomografických řezech fantomu a porovnávány jak subjektivně, tak objektivně pomocí metrik kvality obrazu. Strategie s nejlepšími výsledky byly dále testovány na naměřených CT datech z CT systému Rigaku nano3DX s vysokým rozlišením a byly popsány jejich výhody, omezení a možnosti využití.
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Optimization of the Radiological Protection in Diagnostic X-ray Examinations
GREGOROVÁ, Tereza
This thesis deals with the topic of optimization of radiation protection of patients at a radiodiagnostic workplace. It discusses the possibilities of protecting patients from X-ray radiation in radiodiagnostics, both by technical parameters that can influence the dose and by the use of protective shielding, both in the primary radiation beam and outside it. In the practical part I focused on the calculation of diagnostic reference levels for selected examinations. Examination data was obtained from the DICOM header from the Dicompass viewer. For the calculation, I chose the chest examination in PA projection and the skull examination in AP projection lying on the examination table. Exposure parameters from three stationary scanners on which both selected examinations are currently routinely performed were analyzed. The observed values of input surface kerma and surface kerma for each scans were compared with the values of local diagnostic reference levels and with the values of national diagnostic reference levels. There are no national diagnostic reference levels for pediatric examinations, so I used the 2015 European Guidelines on DRLs for Pediatric Imaging document, which contains diagnostic reference levels for pediatric patients, to compare the values. The content of this paper can serve as a basic overview of optimizing radiation protection and calculating diagnostic reference levels for healthcare professionals and the general public.
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Specifics of the radiodiagnostic examinations in the Hospital of Pelhřimov, p.o.
CHADIMOVÁ, Tereza
Nowadays, sciascopy examinations are increasingly being replaced by other examination methods, which include especially CT examinations, and therefore their number is gradually decreasing. The first goal of the bachelor thesis entitled "Specifics of radio diagnostic examinations in Pelhřimov Hospital, allowance organization", is to describe the history of the radio diagnostic department in Pelhřimov Hospital, allowance organization. The second goal is to analyze trends in imaging methods with a focus on Pelhřimov Hospital, allowance organization, between the years 2009-2018. In the theoretical part I mentioned the history of the radio diagnostic department in Pelhřimov Hospital, allowance organization, and I described contrast agents, their use and distribution. The largest part was devoted to the description of radio diagnostic devices used in Pelhřimov Hospital, allowance organization. These include ultrasound, X-ray machine, computed tomography or skiascopic-skiagraphic wall. Another part of my bachelor thesis contains a description of examinations performed on CT apparatus and skiascopic-skiagraphic wall in Pelhřimov Hospital, allowance organization. For the processing of the practical part I used data obtained from Pelhřimov Hospital, allowance organization, in the form of printed operation logs, with which I created tables. I divided the tables according to the types of examinations and the individual years and compared whether the spectrum of the individual types of examinations on the CT apparatus and the skiascopic-sciagraphic wall have changed in the past ten years. The contribution of this bachelor thesis serves as a background material for the staff of the radio diagnostic department in Pelhřimov Hospital. Furthermore, it is intended to inform the public and other health facilities.
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Sample preparation and their measurement by EDS methods
Kostelník, Tomáš ; Jaššo, Kamil (referee) ; Čudek, Pavel (advisor)
This bachelor´s thesis is focused on preparation and analysis of samples by energy dispersive spectroscopy using scanning electron microscopy. In the theoretical the main differences between environmental scanning electron microscopy and scanning electron microscopy are described. There is also a description of basic knowledge regarding energy dispersive spectroscopy. The generation and detection of signals arising from the interaction of a beam of primary electrons with a sample is also explained, with emphasis on the description, generation and distribution of these signals. The experimental part is focused on sample preparation and analysis.
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Determination of the chemical composition of a brass sample by X-ray fluorescence method
Tomanová, Michaela ; Čudek, Pavel (referee) ; Vaněk, Jiří (advisor)
The fluorescence spectroscopy method is used to distinguish components in gas, liquid, or solid samples. The study is based on the parameters of secondary radiation, which is emitted by each element and allows them to be identified. The distinction between each radiation is analogous to a fingerprint. Apart from quantitative and qualitative analyses, the method can be used to determine the thickness of metal layers and alloys. Laboratory analysis has a broader range of application than portable devices, which are also available. In the laboratory, two methods of measurement are available: wavelength dispersive fluorescence spectroscopy – WDXRF and energo dispersive fluorescence spectroscopy – EDXRF. A brass sample with lead additive was analyzed using EDXRF in the practical part of this diploma thesis. An X-ray apparatus from the Leybold company was employed for the analysis, which will be used for education of lower grades at the university. A measurement station and a laboratory assignment were developed as part of the thesis, the aim of which will be to determine the chemical composition of a brass sample using the X-ray fluorescence method.
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Fluoroscopy in Písek Hospital a.s.
VYSOKOMÝTSKÁ, Jiřina
The Fluoroscopy is nowadays increasingly replaced by other investigative methods, including CT examinations and more. Their number is currently falling slowly. The aim of the bachelor thesis was to analyze the possibilities of Fluoroscopy examinations in Hospital Písek, a.s. during 11 years (2006-2016) and potential substitution by other imaging methods. Another target was to compare the results with the statistics in the Czech Republic, which deals in particular with the total number of digestive tract tests carried out from 2007 till 2015 in all radio-diagnostic facilities. The theoretical part deals with Fluoroscopy and everything that belongs to it. It describes what X-ray radiation and its biological effects are. The largest part is devoted to X-ray techniques, contrast substances and Fluoroscopic examination. Describes parts from which Fluoroscopy is comprising. It also focuses on contrast substances, their classification and what double contrast examination is. The last chapters deal with Fluoroscopic examination, which were carried out at the Písek Hospital, a.s.. The data for a practical part of statistic evaluation was obtained from Písek Hospital, a.s. during the four months from December 2016 till March 2017, data collection was carried out in the form of printed operation report. The data was written in tables for each year separately, then divided into tables according to type of examination, sex and age. The simple abstract of the radiology activities and imaging methods for the period 2007-2015 was downloaded from ÚZIS. The downloaded data was focused only for a gastrointestinal tract radiology and a table to compares the data with the research.
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Module for detection of ionizing radiation
Matějka, Tomáš ; Džbánek, Lukáš (referee) ; Kubíček, Michal (advisor)
This thesis deals with design of detector of ionizing X-ray radiation. Conventional PIN photodiodes are used for construction of the detector. The thesis describes issue of using PIN photodiodes for X-ray and gamma radiation detection. Transimpedance amplifier is designed with two diferent modes of detection. Both amplifier variants are compared and their suitability for specific applications is discussed. The thesis describes principle of converting analog signals to digital and describes concept of bus for multiple detectors connection to central unit. Options for paralel data processing are discused in last part of thesis. The detector is implemented and measured values are compared with simulations.
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