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Data processing for tomographic reconstruction
Dospiva, Jindřich ; Žídek, Jan (referee) ; Zikmund, Tomáš (advisor)
This thesis deal with data processing from x-ray tomographic system. The primary focus is put on the description of projection refining taking place before tomographic reconstruction. The particular method for data processing from system Nano3DX is also suggested. It uses open software ASTRA tomography toolbox, which enable executing of tomographic reconstruction on the graphics card in MATLAB environment. There is also used correction for sample movement, denoising algorithm in projections and calculation the centre of rotation. Results of proposed procedure are demonstrated on tomographic data from measured samples and compared with processing software from the manufacturer.
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X-ray computed tomography of cartilage tissue of embryos
Tesařová, Markéta ; Křivánek,, Jan (referee) ; Zikmund, Tomáš (advisor)
Research of the cartilage is standardly realized by optical microscopy on histological slices. However, for better understanding of shape-organizing processes, imaging in 3D is required. This thesis deals with X-ray computed tomography of mouse embryos. Specifically, it focuses on visualization of craniofacial cartilage. The thesis summarizes the basic principles of X-ray computed tomography. Short research study dealing with staining of soft tissues for X-ray is also provided. The procedure of implementation of the tomographic measurement of mouse embryos stained by PTA is described. This procedure includes the staining protocol, fixing the sample and setting of the CT machine. Subsequent segmentation and creating of a 3D model of cartilage is also desribed. Results for every step of this procedure are demonstrated at the mouse embryos of developmental stage from 12.5 to 17.5 days. In order to improve data quality and standardization of the whole process, parameters of X-ray tube and temperature conditions during the tomographic measurement are explored. Finally, resulting models of craniofacial cartilage are shown with the possibility of subsequent analysis.
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CT X-ray quantitative evaluation
Novotný, Lukáš ; Malínský, Miloš (referee) ; Drastich, Aleš (advisor)
X-Ray Computed Tomography is irreplaceable medical imaging system. Quantitative evaluation is day to day routine used for clean run of this imaging system. The master’s thesis is focused on quantitative evaluation of first and third generation X-Ray CT. First of all is about subjective and objective evaluation of space and energetic resolution. Space resolution is evaluated in space and frequency domain. Energetic resolution is represent by low contrast resolution method. Application “Kvantitativní hodnocení kvality CT RTG zobrazení” created for this thesis is used for creation of reconstruction image and quantitative evaluation. This application was created with consideration of its usage in subjects about image processing. The master’s thesis contains results of quantitative evaluation X-Ray CT created with this application and proposal of lab work.
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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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The X-ray CT lab and the research at the Institute of Geonics AS CR
Souček, Kamil ; Staš, Lubomír
In recent decades, non-destructive methods of materials analysis (Desrues 2006) have been used increasingly for the study of different kinds of materials. Especially, it concerns the method of the X-ray computed tomography (CT). This technique was invented in 1970's (Hounsfield 1972) and it quickly became an indispensable part of medicine. In the 1980's, this success in medicine encouraged the research and development of the X-ray CT applications in the field of materials engineering and consequently also in the field of geomaterials (Otani, Obara 2004). Nowadays, many applications are possible due to high resolution of individual building units in the tomographic cross-sections (so called voxels) with dimensions of units or tens of micrometres. To get this resolution, the use of the 2D and the 3D high-resolution X-ray CT, or the micro-CT with micro-focal sources of X-rays, and suitable linear or flat (2D) X-Ray detectors are preferred.
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