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Low-noise bandgap reference
Knop, Jaroslav ; Fujcik, Lukáš (referee) ; Kadaňka, Petr (advisor)
This work deals with principles of design low noise bandgap reference using multiple in the process EPI92. The voltage reference is described and theoretic analysis noise performances is made. Results are compared with measured data realized breadboard BG reference and fabricated low drop-out regulators, which using different accurate bandgap references cells.
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Optimization of tomographic station GE phoenix adjustment for plastic components including metal parts
Starý, Přemysl ; Petrilak, Michal (referee) ; Zikmund, Tomáš (advisor)
X-ray computed tomography is a tool mostly used in a medical diagnosis. A development of the technique and an improvement an in accuracy of tomographic systems enabled an utilization of the tomography in industrial applications. The tomography allows non-destructive analysis of inner structure. There is a negative influence of a reconstructed area if a low-absorption and high-absorption materials are scanned together. This influence makes analysis of the inner structure impossible. There are two options to eliminate these artifacts. We can use algorithms to reduce metal artifacts, or we can try to avoid them when performing the scan. This bachelor thesis focuses on an optimization of tomographic station adjustment for the plastic components including metal parts. The effect of an usage of X-ray filter or collimator and effect of a sample orientation on data quality will be observed. We use tools like contrast, noise and edge sharpness to evaluate data quality.
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Monitoring the effects of new exposure parameters after transition to CR digital image processing in the Radiodiagnostic Department at Sušice Hospital, o.p.s.
KLIMENT, Karel
At the current time, doses of radiation caused by medical exposure make up the largest part of peoples' exposure to artificial sources of ionising radiation (SIR). Every medical exposure must be justified as of benefit to the individual subject to it. Radiation protection at the workplace is subject to the principle of optimisation. One of the paths leading to optimisation of radiation protection is the specification of the Local Diagnostic Reference Level (LDRL). The objective of this thesis was to test and evaluate whether and how transition to indirect digitisation affects image quality. According to model examinations on a water phantom, the lowest possible dose for which image quality would be preserved was to be determined. If the dose could be reduced, it would be possible to specify a new LDRL. The dose can be reduced, amongst other things, by making appropriate adjustment to exposure parameters on the control unit. I tested how changes in the exposure parameters set affected the quality of the resulting image. I used the water phantom for each examination which corresponded to the thickness of the area to be examined for a standard patient. For constant default voltage, first of all changes to the settings were made to reduced blackening and increase electrical charge. Subsequently, voltage was increased and reduced with a constant blackening level. Image quality was evaluated according to the measured values for noise, and high and low contrast resolution. I used the results to determine recommendations for specific examinations in terms of exposure parameters to be set. I worked out the LDRL for the new exposure parameter settings and compared it to the current LDRL values at the workplace and with the NDRL (National Diagnostic Reference Level).
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Vliv hluku na zdraví člověka a životního prostředí
Ústav experimentální medicíny AV ČR, Praha ; Syka, Josef
Řešení projektu je zaměřeno na výzkum specifických účinků hluku na sluchový systém pokusných zvířat s možností přenosu výsledků na člověka. Pokusná měření byla prováděna na morčatech a laboratorních potkanech. Kromě experimentálního měření bylo hodnocení vlivu hluku zaměřeno na sluchový systém člověka. Účinky sociálního hluku byly studovány u skupiny dobrovolníků, kteří strávili čtyři hodiny na simulované diskotéce.
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