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<p>An electro-optical sensor module was designed to monitor the level of dissolved oxygen (DO) using the method of frequency domain fluoroscopy. Frequency domain fluoroscopy is an optical method that detects the concentration of an analyte by indirectly monitoring the fluorescent lifetime decay. A planar film containing oxygen sensitive fluorophores interacts with a liquid solution, where the percent DO dictates the fluorescent lifetime decay. Amplitude modulated LED emission is created using an electrically implemented oscillator, exciting the oxygen sensitive fluorophores. The emission light from the fluorophores is detected by a photodiode and conditioned. The timing characteristics of the excitation and emission light waveforms are interpreted by a microcontroller. Time delay values have been correlated to actual percent DO values experimentally, and appropriate data modeling has been implemented for calibration purposes. This design is appropriate for application in bioreactors, presenting a functional and cost effective design. Future research can be performed to extrapolate the microcontroller platform to host a pH module, cell number module and glucose module, providing sufficient feedback to an automated bioreactor systems.</p> / Master of Applied Science (MASc)

No / To demonstrate the benefits of fluoroscopy-guided intra-articular steroid injection in the hip with varying degrees of disease severity, and to investigate the financial aspects of the procedure and impact on waiting time. MATERIALS AND METHODS: A prospective study was undertaken of patients who underwent fluoroscopic intra-articular steroid injection over the 9-month study period. Comparative analysis of the Oxford hip pain score pre- and 6-8 weeks post-intra-articular injection was performed. Hip radiographs of all patients were categorised as normal, mild, moderate, or severe disease (four categories) based on the modified Kellgren-Lawrence severity scale, and improvement on the Oxford hip pain score on each of these four severity categories were assessed. RESULTS: Within the study cohort of 100 patients, the mean increase in post-procedure hip score of 7.32 points confirms statistically significant benefits of the therapy (p<0.001, 95% confidence interval: 5.55-9.09). There was no significant difference in pre-injection hip score or change in score between the four severity categories (p=0.51). Significant improvement in hip score (p<0.05) was demonstrated in each of the four severity categories 6-8 weeks post-injection. No associated complications were observed. CONCLUSION: The present study confirms that fluoroscopy-guided intra-articular steroid injection is a highly effective therapeutic measure for hip osteoarthritis across all grades of disease severity with significant cost savings and the potential to reduce waiting times.

Im Rahmen einer experimentellen Vergleichsstudie zweier bildwandlergestützter Navigationssysteme wurde die 3D-bildwandlergestützte Navigation mit der 2D-bildwandlergestützten Navigation zur Pedikelschraubenplatzierung am Modell getestet. Neben der Präzision der Bohrungen in einem postoperativen CT wurden Bildqualität, Genauigkeit des 3D-Scans, Planbarkeit und Umsetzung der Bohrungen bewertet und verglichen. Mit der 3D- Bildwandler- Navigation wurden 38 der 40 Bohrungen exakt platziert (95%). Eine Planung wurde durch einen Softwarefehler der Alpha-Version auf dem Monitor falsch wiedergegeben. Bei einer weiteren Bohrung wurde der Bohrer verkantet, wodurch Bildschirmdarstellung und Realität voneinander abwichen. Daher kam es in einem Fall zu einer lateralen Perforation der Kortikalis im Bereich des Pedikels, im anderen zu einer kaudalen Perforation. Mit der 2D- Bildwandler- Navigation konnten alle 40 Schrauben ohne Pedikelperforation platziert werden. Zwei dieser Schrauben wurden durch die ventrale Kortikalis gebohrt. Beide Verfahren überzeugten durch hohe Präzision und Zuverlässigkeit. 3 der 4 Fehlplatzierungen waren Anwender einer Software bedingt. Eine optimierte Software und verbesserte Instrumente werden diese Fehlerquote weiter reduzieren. Voraussetzung für die 2D-bildwandlergestützten Navigation sind eine gute Bildqualität sowie normale anatomische Gegebenheiten für standardisierte Projektionen. Die neue 3D-bildwandlergestützter Navigation kombiniert die Vorteile der 2D-bildwandlergestützter Navigation und der CT- basierten Navigation mit einer Verringerung der Strahlenbelastung durch den Wegfall des präoperativen CT`s und somit der Einsatzmöglichkeit im akuten Notfall sowie nach intraoperativen Repositionsmanövern. Da kein Matching erforderlich ist, wird insbesondere bei traumatischer Verletzung oder tumorbedingter Veränderung der dorsalen Wirbelstrukturen ein großer Vorteil zur CT- basierten Navigation erwartet. Aufgrund der universellen Einsatzmöglichkeiten eines Bildwandlers wird für diese neue Technologie ein breites Indikationsspektrum angenommen. / An experimental study to compare 2D- and 3D- Computer-Assisted Fluoroscopic Navigation for pedicle screw placement. Each system was evaluated by a post-operative CT and included the comparison of the palpation of the pedicular canal, the image quality and the accuracy of planning and performance. For this purpose 40 screws have been set to 9 models of lumbar spine. Using the 3D-flouroscopy based navigation 38 from 40 (95%) drillings were placed correctly. One mistake was caused by an error of the navigation-software. The second mistake was due to a drilling mistake, the drill was not shown correctly on the monitor because the drill has been canted. Using the 2D-flouroscopy based navigation all screws could be placed correctly at the pedicle, but two times the corpus has been perforated to ventral. Both techniques are precise and reliable. 3 out of 4 mistakes were caused by incorrect handling the instrument. The other mistake happened because of a software-error. If the software and the instruments will be optimised, the amount of mistakes will be reduced in the future. In case of the 2D-flouroscopy based navigation sufficient image quality, normal anatomical structures and defined projections are required. The new 3D-flouroscopy based navigation combines the benefit of 2D-flouroscopy based navigation and CT-based navigation by reducing the radiation exposure and the preoperative planning time. Therefore, this technique is suitable for use in an emergency or intraoperative repositions. Because no matching-procedure is necessary for CT-based navigation, we expect advantages especially in therapy of traumatic injuries or changes at the dorsal structures of spine caused by tumour. Furthermore, the use of fluoroscopic based navigation extends the range of applications/the spectrum of indication for this new technology.

During catheterized x-ray interventions the patient and medical staff is exposed to scatter radiation, as a consequence of tissue interactions. Ionizing radiation for medical purpose is potentially dangerous and can cause malignancy, skin damage and more. Studies have suggested an increase in the prevalence of eye lens cataract, thyroid cancer and left sided brain tumors in doctors. Therefore, it is mandatory to reduce the radiation dose in medicine, a principle known as ALARA (as low as Reasonably Achievable). Lead aprons, collars and shieldings are safety precautions to protect the team in the operating room. The x-ray equipment and surgical techniques are constantly evolving and the interventions become more complex which may increase the x-ray dose. Although x-ray imaging is required in interventional procedures endeavors of reducing radiation exposure to staff is of high interest. There is a need to increase the awareness about scatter radiation and radiation protection efforts are gaining momentum. Initiative to train a dose reducing behavior by education and awareness are key documents within the European Union’s guidelines on Radiation protection. The aims of this thesis were to create a 3D model for representation of real-time exposure and accumulated scatter radiation to staff performing interventional x-ray procedures and identify parameters that affect the scatter radiation. Extensive measurements were made with real time dosimeters while irradiating an anthropomorphic phantom. For five lateral C-arm projections, 68 - 80 data points each were used to measure scatter dose distribution around the patient. In the typical operator position, the effect of craniocaudal projection angle, patient size, field size, image detector height and pulse rate on scatter radiation dose was also investigated. It was possible to create a 3D model from interpolated measurement data that can generate dose rate with promising results. Six out of eight modelled doses deviated +/- 26.6 % from the validation cases. A model that delivers relative dose is an intuitive approach in education for interventional x-ray radiation safety. The staff position in relation to the x-ray source and the patient size have a significant correlation to the dose rate. Additional measurements are needed to ensure the reliability of the model. This work completes the effect of scatter radiation distribution around the patient table, which is not yet evaluated as thoroughly by other authors.

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