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Drug transport using microbubbles
Piňos, Ondřej ; Tancjurová, Jana (referee) ; Rudolf, Pavel (advisor)
This bachelor thesis deals with the research in field of medical usage of microbubbles, specially focused on ultrasound iniciated cavitation of microbubbles filled with drugs. Thesis includes technology of manufacturing, chemical composition, efects of cavitated microbubbles on tissue and description of mechanism that occurs during the aplication of ultrasound triggered microbubbles. Second part deals with mathematical description of microbubble under acustic pressure using the Rayleigh-Plesset equation and equation for microbubble with membrane are presented. The MATLAB script for calculation of physical parameters describing state of microbubble is also explained.
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Study of surface tension of systems applied in ultrasonography.
Říkovská, Klára ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
Surface tension of sonography systems was investigated using several experiments. These experiments were comprised of measurements of surface tension using BPA-800P tensiometer. The influence of surface tension of commercial substance SonoVue®, which contains in its structure two types of phospholipids, was studied more detailed. Other phospholipids were studied to comparison with SonoVue®. All substances were dissolved in saline (0,15 M NaCl). Effect of gas type on microbubbles formation and surface tension was investigated. Some samples were studied using du Nüy ring method. It was found that gas constructing the microbubbles (air or SF6) has no impact to the surface tension value. Production of foam on the surface of solutions has an impact on the value of the surface tension. This foam degreases the surface tension. Gas pressure is significant to comparison of measured data.
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Statistical properties of ultrasound images in contrast mode
Věžníková, Romana ; Kolář, Radim (referee) ; Slávik, Vladimír (advisor)
The bachelor’s thesis is focused on properties of ultrasound images in contrast mode. First of all it describes the basic properties of ultrasound, the way in which the ultrasonic signals are generated, the parameters of ultrasound and ultrasonic imaging modes. Next part deals with harmonic and contrast imaging modes. This part explains principles of these modes as well as the usage of contrast agents and artefacts connected with ultrasound imaging in contrast mode. The thesis also shows the approximation of the amplitude probability density function of ultrasonic images and description of its single models, out of which is chosen the RiIG model (Rician Inverse Gaussian distribution) for approximation of ultrasound images in this case. To gain parameters of amplitude probability density function from ultrasonic data in contrast imaging mode is made the application using Matlab programming environment. Thereafter is the thesis focused on determining equations for dependences of RiIG distribution parameters on known concentrations of contrast agent for ultrasonic data captured in vitro. These equations are useful for determining the unknown concentration of contrast agent used in images captured in vivo and making its dilution function.
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Theranostic systems in sonography
Říkovská, Klára ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This work deals with preparation of microbubble suspension from a mixture of phospholipids, palmitic acid and polyethylene glycol. Properties of prepared systems were studied using bubble tensiometry and dynamic light scattering method and were compared with commercial contrast agent SonoVue®. Suspensions were prepared in various conditions including different atmosphere and increased temperature in some steps of preparation and different solution. Effect of polyethylene glycol addition on surface activity of the system was studied. Surface activity of phospholipids was insignificant. Surface tension decreased with increasing concentration and molecular weight of polyethylene glycol in the system. Effect of different atmosphere and increased temperature showed no substantial trend. It emerged that dynamic light scattering is not suitable for this type of samples because of high polydispersity and phase separation of the system.
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Solubilization in sonographic systems
Überall, Martin ; Klučáková, Martina (referee) ; Mravec, Filip (advisor)
The aim of this thesis was to determine the solubilizing capacity of microbubbles based on SonoVue®, and phospholipids SonoVue® is made of, by using the UV-VIS spectrophotometry. The concentrations of solubilized substances within these systems was further determined. In particular, the properties of natrium dipalmitoylphosphatidylglycerole and distearoyl¬phosphatidylcholine were investigated. The microbubbles were produced using these phospholipids with the addition of polyethyleneglycol and palmitic acid. The solubilizing capacity was determined using hydrophobic solutes Sudan Red G, Oil Red O, 4-Di-2-Asp and Nile Red in order to obtain a model system of solubilized drugs or other hydrophobic substances. The behavior of solutes in phospholipids and our prepared microbubbles were examined in a moderately polar medium – physiological saline solution (0.15 M NaCl). The vizualization of prepared microbubbles was performed using optical and fluorescence microscopy. 4-Di-2-Asp, as a fluorescence probe, was not suitable for microbubble vizualization. The size of microbubbles that were produced during the experiment was almost the same as the size of microbubbles of commercially made SonoVue®. The concentration of solubilized hydrophobic solutes inside the liposomes of phospholipids ranged from tens to hundreds of micromoles per liter. With increasing concentration of phospholipids the concentration of solubilized solutes also increased. The results of this experiment can be used for further research focused on the solubilization of drugs in microbubbles, and contrast agents which are used in ultrasonography.
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Nano and microbubbles created by cavitation
Harazin, Přemysl ; Sluše, Jan (referee) ; Rudolf, Pavel (advisor)
This work solves the problematics of distinguishing tiny bubbles and particles as well as the thermodynamics of bubbles and their creation. The process of cavitation is described in the first part of the thesis. The problem of visualisation and counting the number of bubbles is described in the experimental part as well as the posibility of influencing the stream through the input of obstacles. Problem with visualisation was dealt with laser beam shining through the transparent tube with software postprocessing. The issue of influencing the stream was dealt with input of the strainer into the stream. Results of these experiments are, that with good ambient light situation, the laser beam ensures good visualisation of bubbles and particles and therefore the posibility of counting the number of bubbles with the help of a software. The usage of strainer helped to create bigger number of tiny bubbles.
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Study of system based on phospholipids for sonographical application.
Überall, Martin ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
The aim of this thesis was to determine solubilizing capacity of surfactants and phospholipids using the UV-VIS spectrophotometry. The concentrations of solubilized substances within these systems was further determined. From the surfactant group, three representatives were selected, cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate (SDBS) and Triton X-100. From the phospholipid group, lecithin and commercially available SonoVue® were chosen. The solubilizing capacity was determined using hydrophobic solutes Sudan Red G (SRG), Oil Red O (ORO) and 1-naphtol in order to obtain a model system of solubilized drugs or vitamins which are also hydrophobic. The behavior of solutes in surfactants was determined in a moderate polar medium of physiological saline (0.15 M NaCl), the behavior of solutes in lecithin was conversely determined in Mili-Q water medium. The determined concentration of solubilized hydrophobic solutes inside the micelles of surfactants is within the range of tens to hundreds of micromoles per liter. With increasing concentration of surfactant increases the concentration of solubilized solutes. The results obtained in this work can be used for further experiments and research focused on solubilization of drugs in contrast agents used in ultrasonography.
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Drug transport using microbubbles
Piňos, Ondřej ; Tancjurová, Jana (referee) ; Rudolf, Pavel (advisor)
This bachelor thesis deals with the research in field of medical usage of microbubbles, specially focused on ultrasound iniciated cavitation of microbubbles filled with drugs. Thesis includes technology of manufacturing, chemical composition, efects of cavitated microbubbles on tissue and description of mechanism that occurs during the aplication of ultrasound triggered microbubbles. Second part deals with mathematical description of microbubble under acustic pressure using the Rayleigh-Plesset equation and equation for microbubble with membrane are presented. The MATLAB script for calculation of physical parameters describing state of microbubble is also explained.
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Statistical properties of ultrasound images in contrast mode
Věžníková, Romana ; Kolář, Radim (referee) ; Slávik, Vladimír (advisor)
The bachelor’s thesis is focused on properties of ultrasound images in contrast mode. First of all it describes the basic properties of ultrasound, the way in which the ultrasonic signals are generated, the parameters of ultrasound and ultrasonic imaging modes. Next part deals with harmonic and contrast imaging modes. This part explains principles of these modes as well as the usage of contrast agents and artefacts connected with ultrasound imaging in contrast mode. The thesis also shows the approximation of the amplitude probability density function of ultrasonic images and description of its single models, out of which is chosen the RiIG model (Rician Inverse Gaussian distribution) for approximation of ultrasound images in this case. To gain parameters of amplitude probability density function from ultrasonic data in contrast imaging mode is made the application using Matlab programming environment. Thereafter is the thesis focused on determining equations for dependences of RiIG distribution parameters on known concentrations of contrast agent for ultrasonic data captured in vitro. These equations are useful for determining the unknown concentration of contrast agent used in images captured in vivo and making its dilution function.
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Nano and microbubbles created by cavitation
Harazin, Přemysl ; Sluše, Jan (referee) ; Rudolf, Pavel (advisor)
This work solves the problematics of distinguishing tiny bubbles and particles as well as the thermodynamics of bubbles and their creation. The process of cavitation is described in the first part of the thesis. The problem of visualisation and counting the number of bubbles is described in the experimental part as well as the posibility of influencing the stream through the input of obstacles. Problem with visualisation was dealt with laser beam shining through the transparent tube with software postprocessing. The issue of influencing the stream was dealt with input of the strainer into the stream. Results of these experiments are, that with good ambient light situation, the laser beam ensures good visualisation of bubbles and particles and therefore the posibility of counting the number of bubbles with the help of a software. The usage of strainer helped to create bigger number of tiny bubbles.
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