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Theses, Masters


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The aim of this project was to design and manufacture a respiratory monitoring device that operates in conjunction with MRI scanners to produce higher quality images. The resultant quality of many MRI images depends on how well the patient can control their breathing activity. This research has been successful in designing and manufacturing a device that can be used to teach patients how to hold their breath correctly prior to scanning and also provide them with feedback about their breathing activity during the scan The project involved research into MRI technology and the materials that can still be used in the MRI environment. This heavily influenced the design of the transducer for monitoring breathing and the design of the feedback systems for providing the patient with information about their breathing activity during the scan. The system for breath monitoring is a rubber bladder, which is strapped to the chest of the patient, and is connected to a pressure transducer. This bladder is a low design compared to similar transducers already on the market and tests have shown similar performances between all of them. A number of different feedback systems have been designed that can work together or separately as required. These include a visual method where information is transmitted from a bar graph LED display via polymer optical fibres to the patient. Software was also written to generate a graphical display of the breathing activity and to produce a corresponding audio tone. A requirement of the respiratory monitoring device was for it to be compact and ergonomically designed. Various manufacturing processes were investigated and researched in order to produce a suitable housing for the device. An initial rapid prototype model was made from which new ideas were obtained. It was finally decided to use a vacuum forming process to make the housing from ABS plastic. The European Union Medical Devices Directive was consulted and examined and its rules followed to ensure that the device is in compliance with medical standards. The necessary documentation for CE Making of the finished product has also been prepared. The entire device has been tested within the MRI environment with positive results.



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