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Linear Accelerator Input Beam Data Collection for DIAMOND Calculation Systém Setup
KRÁKORA, Martin
The first chapter of the theoretical part of my bachelor's thesis is focused on the theme of radiotherapy in general as well as to its history. Radiotherapy is a young medical field which treats both malignant and non-malignant diseases by ionizing radiation. The roots of this discipline go back to the beginning of the 20th century, when German physicist Wilhelm Conrad Rontgen discovered X-rays. These rays started to be used in the treatment of tumorous diseases; the first case of tumour elimination by these rays was described in 1896. The second theoretical chapter outlines the types of radiotherapy and their clinical applications. The first type of radiotherapy is curative (radical), which is the primary choice for treatment of tumours, with the aim to eradicate the tumour completely and cure the patient. Another type of radiotherapy is adjuvant. This is a "securing" method, indicated in case of assumption that there are still microscopic tumour remains in the patient's body. There is also neoadjuvant radiotherapy, so-called preoperative. It is applied before the medical procedure when it is necessary to reduce the size of the tumour. Another clinically applied type is radiotherapy with palliative intent. This treatment is indicated to patients whose disease is incurable and serve to remove or alleviate the symptoms. The last type is non-tumorous radiotherapy. This method of treatment is used for non-tumorous diseases and it is always the method of the last resort. The following chapter discusses the theme of radiotherapeutic irradiator. These devices include simulator which simulates the irradiation plan and is very important for planning and control in radiotherapy. Linear accelerators are the most often tools used for irradiation. These accelerators use high-frequency beam of photons or electrons for irradiation. Other devices used in radiotherapy include cobalt and cesium irradiators. The fourth chapter deals with planning in radiotherapy. Irradiation plan, which must be approved by a doctor, is put together in the process of planning. This plan is approved in case when the created combination of irradiation fields achieves the most accurate covering of the target volume by a required dose, and at the same time healthy tissues and organs are spared as much as possible. This chapter also mentions the theme of phantoms that are very important for planning in radiotherapy. Phantoms were also used during the measurement within the practical part of the thesis. The fifth chapter is devoted to irradiation techniques used in radiotherapy. All basic techniques used for irradiation are described here one-field irradiation technique, which is the simplest one, two-field irradiation, i.e. contralateral, convergent or tangential techniques. Also three-field irradiation technique the T and Y techniques, as well as the four-field technique BOX and Crossfire techniques. The most complex techniques include five and more fields where three-dimensional conformational radiotherapy is used. The last chapter describes individual planning systems used at the Department of Oncology of České Budějovice Hospital, with which the objectives of the practical part of the bachelor's thesis were achieved. These planning systems include Mephysto mc2, Diamond and Eclipse programs. Independent measurements were carried out within the practical part of the bachelor's thesis, on the basis of which the following hypothesis was confirmed: "A procedure implemented in compliance with methodology No. 4 can shorten the time of measuring of parameters of ionizing radiation beams from linear accelerator to be entered into the DIAMOND computing system." The aim of the thesis was to get data files for entering the source of ionizing radiation (linear accelerator) into the DIAMOND computing system. This objective was achieved and the respective data files are presented in the chapter of Results (the whole version is attached to this thesis on a CD).
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Design and construction of MR phatoms for MRI
Daňová, Ľudmila ; Odstrčilík, Jan (referee) ; Kudlička, Petr (advisor)
The object of the thesis is the design of the static phantom used in the MRI. It solves the generation of the pictures obtained from the magnetic resonance and its physical principles. The thesis focuses on two types of phantoms - dynamic and static, and especially on phantom used for the LCModel. There is also information about components that will be used for the detection of the spectrums of the selected metabolites.
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Simulation of ultrasound sequences in contrast mode
Staňková, Jana ; Hesko, Branislav (referee) ; Harabiš, Vratislav (advisor)
This bachelor thesis deals with the principle of contrast imaging techniques for ultra-sound imaging. In the first part there are described basic principles and characteristics of ul-trasound waves for the understanding. It is also focused on ultrasound contrast agents used in contrast enhanced ultrasound imaging. The important part is the description of perfusion mo-dels with a focus obtain perfusion parametres and analyze perfusion curves obtained by mea-suring the ultrasound contrast agent over time. The second part is devoted to designing a pro-gram for generating simulated ultrasound images and description of the simulation of 2D ul-trasound tomograms.
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Design and Realization of Phantom for MRI
Šablatura, Martin ; Čáp, Martin (referee) ; Nešpor, Dušan (advisor)
Paper studies the principles of MRI and composition of MR system. Main part of thesis focuses on design, mixing and measurement of solution for MR system phantom. Teoretical part of paper focuses on problematic of MRI and phantoms for MR system, including description of specific phantom, which is then realised. Paper contains methods for designing proposed kind of phantom and its followed measurement. Part of paper also focuses on mathematical models of elaboration of data aquired from measurements.
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Simulation of ultrasound sequences in contrast mode
Staňková, Jana ; Hesko, Branislav (referee) ; Harabiš, Vratislav (advisor)
This bachelor thesis deals with the principle of contrast imaging techniques for ultra-sound imaging. In the first part there are described basic principles and characteristics of ul-trasound waves for the understanding. It is also focused on ultrasound contrast agents used in contrast enhanced ultrasound imaging. The important part is the description of perfusion mo-dels with a focus obtain perfusion parametres and analyze perfusion curves obtained by mea-suring the ultrasound contrast agent over time. The second part is devoted to designing a pro-gram for generating simulated ultrasound images and description of the simulation of 2D ul-trasound tomograms.
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Contrast MRI perfusion imaging
Šejnoha, Radim ; Harabiš, Vratislav (referee) ; Krátká, Lucie (advisor)
This semestral thesis is focused on contrast MRI perfusion imaging using method of Dynamic Contrast-Enhanced MRI. It describes basic principles of nuclear magnetic resonance and puls sequences used in DCE MRI. The thesis contains a part dedicated to dynamic contrast imaging of phantom with experimental NMR device located at the Institut of Scientific Instruments of the ASCR in Brno. Results of measurements are analyzed based on models and reached perfusion parameters are discussed.
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Optimization of the MRI chicken embryos measurements
Sedláčková, Gabriela ; Dražanová, Eva (referee) ; Krátká, Lucie (advisor)
This thesis deals with optimization of MRI measuring of phantoms containing the chicken embryo. The theoretical part of thesis is dedicated to the MRI fundamentals and description of pulse sequences. In the next part the options of keeping and monitoring the temperature are being discussed. The thesis also deals with design and realization of phantoms which are used for measuring. A browser of images captured by MRI was programmed in Matlab environment. The program allows users to look through the images with different settings of pulses sequences or kind of phantom. The final part of thesis describes the anatomical structures of chicken embryo and discussion of collected results.
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Properties of ultrasound probes
Rusina, Michal ; Mézl, Martin (referee) ; Harabiš, Vratislav (advisor)
This master thesis deals with the measurement properties of ultrasound probes. Ultrasound probes and their parameters significantly affect the quality of the final image. Values of pa-rameters of the probes may change due to their use, because probes may be damaged and the final image may no longer be correct. For these reasons the measurements of parameters of probes are very important. In this master thesis there are described and implemented the possibility of measuring the spatial resolution, focal zone, the sensitivity of the probe and measuring the length of the dead zone. Two ultrasonic phantoms were used for measuring. In the practical part there was created the program called Mereni_parametru, which allows to determine the value of four parameters from captured images of the phantom. Further, there are listed and described measured values for five ultrasonic probes. Results for two of these probes are then compared with the parameters given by the manufacturers.
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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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The Difference between Planed and Real Measured Dose under the Bolus Made of New Material
KUKAČKOVÁ, Lucie
The first chapter of the theoretical part of the bachelor's thesis outlines radiotherapy in general. Radiotherapy is a clinical treatment using ionising radiation to treat malignant and benign diseases. It is one of the youngest medical disciplines. The development of radiotherapy began in November 1895, when Wilhelm Conrad Röntgen discovered X-rays. Radiotherapy became an independent medical specialty in 1922. The second chapter describes planning in radiotherapy. Irradiation plans for radiotherapy are created on the basis of a planning system. ECLIPSE planning system is used in the oncology department in České Budějovice Hospital. Phantoms are the theme of the third chapter. Phantoms are materials whose radiation absorption corresponds to human tissue. Water is a basic universal phantom material. In addition to water, also other materials are used, such as polystyrene, plexiglass, paraffin, PMMA etc. The last, fourth chapter of the theoretical part, deals with boluses. Boluses are tissue-equivalent materials that are put on the patient's skin during irradiation when it is needed to increase the surface dose and at the same decrease the depth dose. Moreover, bolus is used to compensate the missing tissue. Bolus is most often used to diagnose patients after mastectomy due to breast cancer. The most important characteristic of boluses is their ability to absorb radiation. In the oncology department in České Budějovice Hospital, bolus from dental wax Ceradent had been used before. A bolus made from this material was hard and uneasy to shape. That is why it did not fit tightly to the chest wall of the patient. For this reason a new line of boluses was obtained for the oncology department, from gel material supplied by CIVCO company with dimensions 30 x 30 cm and thickness 0.3 cm, 0.5 cm and 1 cm, in "skin" and "skinless" version. These new boluses stick easily to the patient's skin and copy the shape of the body. The first objective of my bachelor's thesis was to compare the doses planned and measured under the bolus from the new material. This objective is elaborated in the practical part of the bachelor's thesis in chapter presenting the results. Another objective was to elaborate the principles for the use of bolus. These principles are described in the theoretical part of the bachelor's thesis in chapter describing the use of bolus in radiotherapy. The following hypothesis was suggested in the thesis: "It can be assumed that the generated bolus in the planning system corresponds to the scanned bolus on the CT with patient and that there is a difference between the planned dose and measured one." To confirm or refute the working hypothesis, measuring was executed in the oncology department in České Budějovice Hospital. Data about individual doses were collected boluses generated in the Eclipse planning system of different width (0.3 cm, 0.5 cm, 1 cm) on phantoms. Three types of phantoms from PMMA were used for the purposes of this measuring. First, the measuring was executed on phantom in the shape of the chest wall of a patient after breast ablation. Then, the tabular phantom and universal IMRT verification phantoms were used. The measurement was executed on the Clinac 2100 C/D linear accelerator, later on the new TrueBeam 2.5. linear accelerator. All these doses were measured by ionisation chamber from PTW company with volume of 0.125cm3. The obtained data were processed in tables and deviations of individual doses were calculated. Based on this measurement it was found out that the deviations of all doses are less than 3%. And therefore also the hypothesis of the thesis was confirmed. There really is a difference between individual doses, but not so significant to affect the size of dose during the planning. As for the practical outcome, generated boluses will be used as standard in the oncology department in České Budějovice Hospital.
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