Tumor functional volume (FV) and its mean activity concentration (mAC) are the quantities derived from positron emission tomography (PET). These quantities are used for estimating radiation dose for a therapy, evaluating the progression of a disease and also use it as a prognostic indicator for predicting outcome. PET images have low resolution, high noise and affected by partial volume effect (PVE). Manually segmenting each tumor is very cumbersome and very hard to reproduce. To solve the above problem I developed an algorithm, called iterative deconvolution thresholding segmentation (IDTS) algorithm; the algorithm segment the tumor, measures the FV, correct for the PVE and calculates mAC. The algorithm corrects for the PVE without the need to estimate camera’s point spread function (PSF); also does not require optimizing for a specific camera. My algorithm was tested in physical phantom studies, where hollow spheres (0.5-16 ml) were used to represent tumors with a homogeneous activity distribution. It was also tested on irregular shaped tumors with a heterogeneous activity profile which were acquired using physical and simulated phantom. The physical phantom studies were performed with different signal to background ratios (SBR) and with different acquisition times (1-5 min). The algorithm was applied on ten clinical data where the results were compared with manual segmentation and fixed percentage thresholding method called T50 and T60 in which 50% and 60% of the maximum intensity respectively is used as threshold. The average error in FV and mAC calculation was 30% and -35% for 0.5 ml tumor. The average error FV and mAC calculation were ~5% for 16 ml tumor. The overall FV error was ~10% for heterogeneous tumors in physical and simulated phantom data. The FV and mAC error for clinical image compared to manual segmentation was around -17% and 15% respectively. In summary my algorithm has potential to be applied on data acquired from different cameras as its not dependent on knowing the camera’s PSF. The algorithm can also improve dose estimation and treatment planning.

No description available.

This thesis describes new trends in the automotive industry. It investigates how these trends altered the automotive market and industry and what are the reasons of it. The thesis then ascertains an impact on the new cars business, in which stress is put on new technologies and automotive market development in the world, with emphasis on the Czech Republic within the crisis period. The thesis follows 2 trend groups, namely the trends that already appear for a longer time as well as the quite new trends influencing substantially the automotive market. The first named group deals with the technological innovations as well as for example with the problem concerning car factories model families expanding with the aim to maximize volume of sale; problems of the car new models safety and performance is another topic of this thesis. As another important topic of this group diesel drive phenomenon problems in the European Union can be taken into account as well as additional burden of taxation for cars with higher fuel consumption connected with it. A significant part of the second group comprises financial crisis development and impact on the new cars sale in a given period. In addition to it, it describes quite new trends, e.g. engine capacity decreasing with the use of supercharged engines (downsizing), coming wave of SUV cars and a phenomenon of four-wheel drive cars. In the final part of this diploma paper problems are analyzed and finally hybrid cars development as well.

This thesis deals with market launch of new model generation of Hyundai Tucson on Czech market. Suggestions a recommendations for new model launch are supported by detailed analysis based on intern sources and secondary data, which are divided to several following parts: Czech automotive market analysis, analysis of Sport Utility Vehicles, consumer insight analysis of previous model generation, introduction of new generation and its key features, competitors overview and comparison with them, marketing communication of Hyundai carmaker, previous model generation and its competitors and positioning. Conclusion and target of this thesis are proposals and recommendations to new model generation launch focused on product, target group, competitors and communication.

Flour-etyl-L-tyrosin positronemissionstomografi (FET-PET) undersökning är en undersökningsmetod som har hög sensitivitet och specificitet vid diagnostisering av bland annat tumör och tumörrecidiv. För att bestämma FET-upptaget i tumören kan tumör till bakgrundsförhållande (TBR) beräknas. TBR är förhållandet mellan upptag i tumör och upptaget i grå och vit substans. Syftet med studien var att kartlägga hur olika rekonstruktioner påverkar värdet av TBR vid FET-PET undersökningar genom att studera TBR vid olika tidsintervall och sex olika rekonstruktioner. Vid genomförande av studien inkluderades 15 patienter med FET-upptag som genomgått FET-PET undersökning i Klinisk Neurofysiologi på Skånes Universitetssjukhus (SUS) i Lund. Hela undersökningstiden 30 minuter, sista 20 minuter samt sista 15 minuter testades för att se om dagens bildtagningsprotokoll går att optimera. Rekonstruktionsmetoderna QClear (QC) och Ordered Subset Expectation Maximization (OSEM) användes i studien. Vid beräkning av TBR-värden användes standardiserade upptagsvärden (SUV). För att beräkna TBR ritades region av intresse (ROI), ROIthreshold samt ROIsfär, över tumörområdet samt i frisk grå och vit substans i den kontralaterala hemisfären, för att bestämma FET-upptaget i förhållande till varandra. TBR beräknades utifrån maximala (SUVmax) och medelvärdet (SUVmedel) i ROI och benämns som TBRmax och TBRmedel. Resultatet av studien visade att ett lägre -värde för QC erhåller högre TBR-värden. TBR-värdena för rekonstruktionsmetoden OSEM låg mellan TBR-värdena för QC-rekonstruktionerna. Medelvärdet av den procentuella skillnaden, av alla patienter, mellan TBR-värden och de olika tiderna, för respektive rekonstruktionsmetod låg mellan 5-10 %. Detta indikerar att mängden injicerad aktivitet till patienten alternativt undersökningstiden kan minskas. Den maximala procentuella skillnaden av TBRmax och TBRmedel för ROIthreshold respektive ROIsfär mellan de olika rekonstruktionerna för alla tre tiderna och alla 15 patienterna, låg mellan 25-40 %. Medelvärdet av den procentuella skillnaden av TBRmax och TBRmedel för ROIthreshold respektive ROIsfär mellan de olika rekonstruktionerna för alla tre tiderna och alla 15 patienterna, låg mellan 15-25 %. Slutsatsen för denna studie är att den kvantitativa bedömningen av TBR-värdet varierar beroende på använd rekonstruktionsmetod. / Flourethyl-L-tyrosine positron emission tomography (FET-PET) examination is an examination method that has high sensitivity and specificity in diagnosing tumors and tumor recurrence. Tumor-to-background-ratio (TBR) could be calculated to determine FET-uptake in the tumor. TBR is the ratio between uptake in tumor and uptake in gray and white matter. The purpose of the study was to identify how different reconstructions affect the value of TBR in FET-PET examinations by studying the TBR-value at different time intervals and six different reconstructions algorithms. In the study, 15 patients were included, all with FET-uptake and all had performed a FET-PET examination at the department of Clinical Neurophysiology at Skåne University Hospital (SUS) in Lund. The entire examination time 30 minutes, the last 20 minutes and the last 15 minutes were tested to evaluate if the imaging protocol used today can be optimized. The reconstruction methods used in the study were QClear (QC) and Ordered Subset Expectation Maximization (OSEM). Standardized uptake values (SUV) were used during the calculation of TBR-values. To calculate TBR, the region of interest (ROI), ROIthreshold and ROIsphere were drawn. ROIthreshold and ROIsphere were drawn over the tumor area and in grey- and white matter in the contralateral hemisphere, to determine FET-uptake in relation to each other. The TBR-value was calculated based on maximum- (SUVmax) and mean values (SUVmedel) in ROI and is referred as TBRmax and TBRmean. The results of the study showed that a lower -value for QC obtains higher TBR-values. The TBR-values for the OSEM reconstruction method were between the TBR-values of the QC reconstruction methods. The mean value of the percentage difference, of all patients, between TBR-values and the different times, for each reconstruction method were between 5-10 %. These results indicate that the amount of injected activity to the patient or the examination time can be reduced. The maximum difference in percentage of TBRmax and TBRmean for ROIthreshold respective ROIsphere between the reconstructions for the tree times and all the 15 patients, were between 25-40 %. The mean percentage difference of TBRmax and TBRmean for ROIthreshold respective ROIsphere between the reconstructions for the tree times and all the 15 patients, were between 15-25 %. The conclusion of this study is that the TBR-value will vary with different reconstruction methods.

In der aktuellen UDV-Studie wurde untersucht, wie SUV-Fahrer:innen im Vergleich zu Pkw-Fahrer:innen den Straßenverkehr wahrnehmen und wie sie sich verhalten. Dabei wurden explizit die Fahrer:innen gebraucht gekaufter SUV einbezogen, um sie mit Fahrer:innen neuer SUV vergleichen zu können.

La Tomographie par Emission de Positons (TEP) au Fluoro-déoxyglucose marqué au Fluor 18 (¹⁸F-FDG), analogue du glucose, permet d'obtenir une image de la consommation de glucose dans l'organisme. La plupart des foyers tumoraux présentant une consommation excessive de glucose, son utilisation en oncologie permet d'améliorer la prise en charge des patients en diminuant le temps nécessaire pour évaluer l'efficacité des traitements tels que la chimiothérapie et la radiothérapie. Mon projet de recherche visait à proposer et améliorer des méthodes de quantification en TEP au ¹⁸F-FDG afin de caractériser au mieux l'évolution métabolique des volumes tumoraux.De nombreux facteurs biaisent la quantification en TEP. Parmi eux, l'Effet de Volume Partiel (EVP) reste difficile à corriger, notamment à cause de la faible résolution spatiale des images TEP. Afin de déterminer l'impact de la correction de l’EVP sur l’évaluation des réponses des tumeurs, une étude sur données simulées par Monte Carlo a tout d’abord été effectuée. Cette étude a été complétée par l’analyse de données TEP/TDM (Tomodensitométrie) acquises chez 40 patients atteints de cancers colorectaux métastatiques (CCM), traités par chimiothérapie à l'Institut Jules Bordet (Bruxelles). L’analyse de 101 tumeurs a montré que les critères tels que le SUV, n’incluant pas de correction de l'EVP, et qui reflètent alors le volume tumoral et son activité, prédisaient mieux l’évolution tumorale que les critères corrigés de l’EVP. Compte tenus des résultats prometteurs récents de méthodes de caractérisation de l’hétérogénéité de la fixation du FDG dans les tumeurs, un second volet de notre travail a consisté à étudier l’intérêt de la prise en compte de la texture dans le cadre du suivi thérapeutique. L’application de l’analyse de texture aux cas de CCM étudiés précédemment n’a pas permis de démontrer une valeur ajoutée des indices de texture par rapport aux index quantitatifs couramment employés en clinique. Nous avons montré que cette conclusion s’expliquait en partie par la non-robustesse des indices de texture vis-à-vis des paramètres impliqués dans leur mesure. Nous avons enfin cherché à évaluer une méthode d’Analyse Factorielle de Séquences d’Images Médicales (AFSIM), appliquée au contexte du suivi thérapeutique, pour caractériser l’évolution tumorale tout au long du traitement. Cette étude a porté sur 9 séries de 4 à 6 examens TEP/TDM de patients traités par radiothérapie au Centre Hospitalier Universitaire Henri Becquerel de Rouen. Outre l’information visuelle globale apportée par cette méthode, l’analyse quantitative des résultats obtenus a permis de caractériser l’hétérogénéité de la réponse vue par l’AFSIM. L’échec des index classiques, provenant entre autres de leur incapacité à distinguer les processus inflammatoires de l’activité métabolique tumorale, a permis de monter la valeur ajoutée de l’AFSIM par rapport aux index tels que le SUV maximal ou moyen. / Positron Emission Tomography (PET) using ¹⁸F-FluoroDeoxyGlucose (¹⁸F-FDG), a radiolabelled analogue of the glucose, is used to get an image of the glucose consumption in the body. As most tumor masses show a high glucose consumption, PET is widely used in oncology for diagnosis and patient monitoring. In the context of patient monitoring, the motivation is to decrease the time interval needed to assess treatment (radiotherapy or chemotherapy efficieny) compared to therapeutic follow-up based only on anatomic imaging only (Computed Tomography or Magnetic Resonance Imaging). My research project aimed at proposing and improving quantitative methods in FDG-PET to better characterize tumor evolution.In PET, many factors affect the accuracy of parameters estimated from the images. Among them, Partial Volume Effect (PVE) remains difficult to correct, mainly due to the low spatial resolution of PET images. To determine the impact of PVE on treatment response evaluation, a preliminary study was performed using Monte Carlo simulated PET scans. An additional study was conducted based on the analysis of the PET/CT (Computed Tomography) data of 40 Metastatic Colorectal Cancer (MCC) patients treated with chemotherapy at the Jules Bordet Institute (Brussels, Belgium). The analysis of the 101 tumors showed that criteria such as the Standardized Uptake Value (SUV), which does not include PVE correction, were better predictors of tumors evolutions than PVE corrected criteria. This is because without PVE correction, SUV includes information on both metabolic volume and metabolic activity, which are two relevant pieces of information to characterize the tumor. A second part of our work was to study the potential of tumor texture analysis in patient monitoring, following promising results reported in the literature. Texture analysis was applied to the MMC patients data previously mentioned but did allow to a better segregation of tumors responses as compared to indices currently used in the clinics. We found that this was partly due to the lack of robustness of the textures indices.Finally, we evaluated a Factor Analysis in Medical Images Series (FAMIS) method to characterize tumor evolution during treatment. This study focused on 9 series of 4 to 6 PET/CT scans acquired all along the radiotherapy/radio-chemotherapy of patients treated at the Centre Hospitalier Universitaire Henri Becquerel (Rouen, France). In addition to the rich visual information brought by this method, a quantitative analysis of the results made it possible to characterize response heterogeneity as seen using FAMIS. In particular, FAMIS clearly demonstrated the occurrence of inflammatory processes. In addition, due to the low metabolic activity of the tumors at the end of the treatment, many conventional indices could not describe the tumor changes, while FAMIS gave a full assessment of the tumor change over time.

En oncologie ORL, l'imagerie multiparamétrique est utilisée par un nombre grandissant d'équipes. Parmi les bio-marqueurs, la captation normalisée du fluoro-désoxyglucose (SUV-FDG) en tomoscintigraphie par émission de positons (TEP) et la restriction de la diffusion en IRM (DWI-MRI) sont les plus utilisées.L'IRM couplée à la TEP (TEP/IRM) est une nouveauté qui permet une diminution très significative des doses d'irradiation délivrées par rapport à la TEP/TDM. Nous adressons notre première expérience concernant l'aspect en diffusion et en TEP/IRM dans la surveillance des patients après radio-chimiothérapie. A la question de l'interchangeabilité du FDG-PET et de la DWI-MRI, nous avons tenté d'identifier un lien en imagerie entre la cellularité tumorale et sa consommation glucidique. La cellularité tumorale est approchée en IRM par la mesure du coefficient apparent de diffusion (ADC) et son métabolisme glucidique est approché en TEP en utilisant le 18F-desoxyglucose (FDG) par la mesure de la valeur de fixation normalisée (SUV). Dans une série appariée de 33 patients, nous avons analysé la reproductibilité des mesures de l'ADC et de SUV. Puis nous avons évalué l'indépendance statistique de ces biomarqueurs. Nous avons ensuite voulu comparer les résultats de la TEP obtenus à partir de la TEP/TDM et de la TEP/IRM. Dans une série prospective appariée chez 32 patients explorés en FDG-TEP, nous avons évalué qualitativement les images obtenues par la fusion des images recalées en TEP/IRM et TEP/TDM. Nous avons ensuite comparé la pertinence clinique des deux techniques. Et enfin nous avons comparé les valeurs quantitatives de SUV obtenues du tissu sain et du tissu pathologique. / Multiparametric imaging interest and clinical use is rising for head and neck carcinoma (HNC). Among these modalities, FDG in PET and DWI-MRI are the most studied. PET/MRI is a new modality that allows in a single examination of combined various biologic biomarkers.After an optimization process of PET/MRI, we applied our first experience concerning the aspects of DWI-MRI and PET-MRI after radiation therapy. Thereafter we studied the correlation of SUV and ADC in HNC. In this study SUV and ADC values were independent parameters in HNSCC. Measurements of these two biomarkers were reproducible with almost perfect observer agreements for both methods. Neither SUV nor ADC values were able to predict the histologic grade, although a trend towards higher SUV and lower ADC values was observed in poorly differentiated tumours. Secondly, we we studied detection and quantification of focal uptake in head and neck tumours: 18F-FDG PET/MRI versus PET/CT in 32 consecutive HNSCC who underwent 18F-FDG PET/MRI and PET/CT. Attenuation correction sequence for PET/MRI and CT for PET/CT were used to caculate SUV. In results, PET/MRI coregistration and image fusion was feasible in all patients. There was no statistically significant difference between PET/MRI and PET/CT regarding rating scores for image quality, fusion quality, lesion conspicuity or anatomic location, number of detected lesions and number of patients with and without malignant lesions. A high correlation was observed for SUV measured on PET/MRI and PET/CT. SUV measured on PET/MRI were significantly lower than on PET/CT for malignant tumours, metastatic neck nodes, benign lesions, bone marrow, and liver (p <0.05).

The thesis deals with the issue of measuring the height of the center of gravity of SUV´s. The first part of thesis is devoted to the issue of center of gravity and the influence of the height of the center of gravity on driving stability. Furthermore, individual methods of measuring the height of the center of gravity in passenger cars are discussed. The analytic part of the thesis is devoted to experimental measurement of the height of the center of gravity of selected SUV´s at different vehicle load, by the method of tilting the vehicle on the axle. The results of the measurements showed that the height of the center of gravity for vehicles with a capacity for five people is in the range from 606 to 697 mm. The lowest value belongs to the vehicle Toyota RAV4 Hybrid, when loaded by the driver. The highest value was found for the vehicle Kia Sportage, when loaded by three passengers. The Landover Defender, which is vehicle, that has a capacity for nine people, was found to have a height of center of gravity ranging from 705 to 874 mm. The lowest value was found when loaded by the driver, the highest value when loaded by nine passengers. Only for the Nissan Qashqai was the growing dependence between the load increase and the height position of the vehicle's center of gravity confirmed. A similar trend was found for the Toyota RAV4 Hybrid, Jeep Compass and Landover Defender. The determined values can be used in the analysis of traffic accidents of SUV’s.

Rollover prevention in Sports Utility Vehicles (SUV‟s) offers a great challenge in vehicle safety. By reducing the body roll angle of the vehicle the load transfer will increase and thus decrease the lateral force that can be generated by the tires. This decrease in the lateral force can cause the vehicle to slide rather than to roll over. This study presents the possibility of using slow active suspension control to reduce the body roll and thus reduce the rollover propensity of a vehicle fitted with a hydro-pneumatic suspension system. The slow active control is obtained by pumping oil into and draining oil out of each hydro-pneumatic suspension unit individually. A real gas model for the suspension units as well as for the accumulator that supplies the oil is incorporated in a validated full vehicle Adams model. This model is then used to simulate a double lane change manoeuvre performed by a SUV at 60 km/h and it is shown that a significant improvement in body roll can be obtained with relatively low energy requirements. The proposed control is successfully implemented on a Land Rover Defender test vehicle. A Proportional-Derivative (PD) controller is used to control on-off solenoid operated valves and the flow is adjusted using the lateral acceleration as a parameter. Experimental results confirm that a significant improvement in body roll is possible. AFRIKAANS : Omrolvoorkoming in Sportnutsvoertuie bied geweldige uitdagings in terme van voertuigveiligheid. Deur die rolhoek van die voertuig te verminder word die laterale lasoordrag verhoog en word die laterale krag wat die bande kan genereer minder. As die laterale krag genoeg verminder sal die voertuig eerder gly as omrol. Die studie ondersoek die moontlikheid om stadig-aktiewe suspensiebeheer op 'n voertuig met 'n hidropneumatiese suspensie te gebruik om bakrol te verminder en dus die omrolgeneigdheid van die voertuig te verlaag. Die beheer word toegepas deur olie in elke hidropneumaties suspensie-eenheid individueel in te pomp of te dreineer. 'n Werklike gas model word gebruik om die supensie-eenhede asook die akkumulator, wat die olie aan die suspensie voorsien, te modeleer. Hierdie modelle word in 'n gevalideerde volvoertuig ADAMS model geïnkorporeer en 'n dubbel laanverwisseling word gesimuleer teen 60 km/h. Die resultate toon dat 'n beduidende verbetering in die rolhoek moontlik is met relatiewe lae energievereistes. Die voorgestelde beheer is suksesvol op 'n Land Rover Defender geïmplimenteer en 'n Proportioneele-Differensiaal (PD) beheerder word gebruik om die aan-af solenoїde kleppe te beheer terwyl die vloei aangepas word na gelang van die laterale versnelling. Eksperimentele resultate bevestig dat 'n beduidende verbetering in bakrol moontlik is. / Dissertation (MEng)--University of Pretoria, 2012. / Mechanical and Aeronautical Engineering / unrestricted