Cone-beam computed tomography (CBCT) is an imaging technique used in conjunction with radiation therapy. CBCT is used to verify the position of tumours just prior to radiation treatment session. The accuracy of the radiation treatment of thoracic and upper abdominal tumours is heavily affected by respiratory movement. Blurring artefacts, due to the movement during a CBCT scanning, cause misregistration between the CBCT image and the planning image. There has been growing interest in the use of motion-compensated CBCT for correcting the breathing-induced artefacts. A wide range of iterative reconstruction methods have been developed for CBCT imaging. The direct motion compensation technique has been applied to algebraic reconstruction technique (ART), simultaneous ART (SART), ordered-subset SART (OS-SART) and conjugate gradient least squares (CGLS). In this thesis a dual modality imaging of electrical impedance tomography (EIT) and CBCT is proposed for the first time. This novel dual modality imaging uses the advantages of high temporal resolution of EIT imaging and high spatial resolution of the CBCT method. The main objective of this study is to combine CBCT with EIT imaging system for motion-compensated CBCT using experimental and computational phantoms. The EIT images were used for extracting motion for a motion-compensated CBCT imaging system. A simple motion extraction technique is used for extracting motion data from the low spatial resolution EIT images. This motion data is suitable for input into the direct motion-compensated CBCT. The performance of iterative algorithms for motion compensation was also studied. The dual modality CBCT-EIT is verified using experimental EIT system and computational CBCT phantom data.

For over a century Pentecostal historiography has superficially recognised Pastor Joseph Smale as one of many individuals involved in the chain of events leading up to the 1906 Azusa Street Revival in Los Angeles. However, an in-depth biographical assessment of Smale’s unique contribution has, to date, never been attempted. Therefore, this thesis provides the first analysis of Smale as a person and as a pastor, thus furnishing Pentecostal and Baptist historiographies with important biographical and theological insights that otherwise would have remained hidden beneath the surface of the Azusa Street storyline. These research findings are also innovative with regard to the connections between CH Spurgeon and Smale, such that this thesis proposes a distinct “Spurgeonic” root, among the multiple roots that were intrinsic to the emergence of Pentecostalism. The primary method involved establishes a correlation of the true biographical facts, while constructing valid opportunities to accurately detect Smale’s own “voice” speaking. Thus, having traced Smale’s pastoral formation within the context of his training at Spurgeon’s College and on into subsequent pastorates, the research explores the contextual preparation for Smale’s anticipation for revival. James E Loder’s model “The Logic of Transformation” is utilised as a framework for the purpose of structuring the incremental stages of Smale’s convictional insights. Smale’s role prior, during and after the 1905-06 revival in Los Angeles is then analysed with a view to establishing the extent of his Pentecostal life and practice. In particular, his preaching, ecclesiology and missiology are the focus of examination in light of early Pentecostalism, whilst also explaining in part Smale’s subsequent disaffection with the Pentecostal movement. Theologically, Smale’s roots are noted to combine during the revival period, integrating Wesleyan views of sanctification with the Spurgeonic emphasis that “The Pentecostal Blessing” would provide the impetus for intensifying sanctification and anointing for service. In conclusion, the legacy of Smale's ministry is recalibrated, suggesting that his "Word" and "Spirit" teaching and experiences could yet contribute a useful case study to progress ecumenical dialogue between Reformed and Pentecostal/Charismatic constituencies, and those researching the relationship between "organization" and "freedom" in the Spirit.

This thesis examines how an officer with so many perceived detractors reached senior leadership positions in the Royal Air Force of the Second World War; that officer is Air Chief Marshal Sir Trafford Leigh-Mallory. Utilising prosopography as a methodology, and grounded in an understanding of leadership theory, though recognising the limitations of applying modern language to historical analysis, this thesis surveys the development processes used by the RAF to nurture officers for senior positions. Furthermore, this thesis argues that the RAF, bounded by the Service’s culture and ethos, took an interest in the leadership development of its officer class as it had a stake in producing able leaders capable of defending its independence. This was done through modern conceptions, such as socialisation, job assignments, action learning and nurturing. These concepts formed the basis of nurtured officers shared experiences, and this thesis illustrates how Leigh-Mallory was representative of the type of officer the RAF wanted to lead the Service. The experiences outlined in this thesis focus on training, education and job assignments, which included aspects, such as the importance of Staff College attendance, command experience and staff duties. Participation in these key shared experiences made officers such as Leigh-Mallory ‘visible’ to those able to further nurture officers careers while giving them the knowledge required to lead at the senior level. By understanding the culture and context of the development of the senior leadership of the RAF of the Second World War, this thesis now allows for a more considered understanding of the effectiveness of officers such as Leigh-Mallory during that conflict.

Cardiovascular disease remains the commonest cause of death worldwide. The majority of deaths are caused by atherosclerotic plaque rupture with resultant myocardial infarction or stroke, or rupture of abdominal aortic aneurysms. Conventional imaging modalities have consistently failed to identify atherosclerotic plaques or aneurysms with high-risk pathological features that are at highest risk of rupture or progression. The development of modern molecular imaging techniques targeted at these features could lead to the identification of such high-risk plaques and aneurysms in vivo and guide the development of novel treatment strategies. The aim of this thesis was to evaluate whether novel molecular modalities have a role in providing new insights into biological disease processes, and identify high-risk plaques and aneurysms. Using positron emission tomography-computed tomography (PET-CT), 18F-fluorodeoxyglucose and 18F-fluoride were utilised as markers of metabolic inflammation and active calcification. Cellular inflammation was assessed using ultrasmall superparamagnetic particles of iron oxide (USPIO) enhanced magnetic resonance imaging (MRI). In a prospective trial, 80 patients with myocardial infarction (n=40) and stable angina (n=40) underwent 18F-fluoride and 18F-fluorodeoxyglucose PET-CT, and invasive coronary angiography (Chapter 3). Intense 18F-fluoride uptake localised to recently ruptured plaque in patients with acute myocardial infarction. In patients with stable coronary artery disease, 18F-fluoride uptake identified coronary plaques with high-risk features on intravascular ultrasound. 18F-fluoride PET-CT is the first noninvasive imaging method to identify and localise ruptured and high-risk coronary plaques. Aortic vascular uptake of 18F- fluorodeoxyglucose was studied in patients with myocardial infarction and stable angina (Chapter 4). In a separate outcome of 1,003 patients enrolled in the Global Registry of Acute Coronary Events, we further evaluated whether infarct size predicted recurrent coronary events. Patients with myocardial infarction had higher remote atherosclerotic tracer uptake that correlated with the degree of myocardial necrosis, and exceeded that observed in patients with stable coronary disease. The outcome cohort demonstrated that patients with higher degree of myocardial necrosis had the highest risk of early recurrent myocardial infarction. This supports the hypothesis that acute myocardial infarction exacerbates systemic atherosclerotic inflammation and remote plaque destabilization: myocardial infarction begets myocardial infarction. In a prospective imaging cohort, the role inflammation and calcification was assessed in 63 patients with abdominal aortic aneurysms and 19 age and sex matched patients with atherosclerosis (Chapter 5). Compared to non-aneurysmal segments, enhanced inflammation and calcification was observed within the wall of aortic aneurysmal segments. In comparison to matched controls with atherosclerosis, the entire aorta in those with aortic aneurysm appears more highly inflamed, suggesting presence of a global aortopathy rather than a disease confined only to the abdominal region of the aorta. Aortic aneurysms have greater active inflammation and calcification than atherosclerotic controls suggesting a more intense, destructive and transmural pathological process. A subgroup of fifteen patients with aortic aneurysms underwent imaging with both PET-CT with 18F-fluorodeoxyglucose, and T2*- weighted MRI before and 24 h after administration of USPIO (Chapter 6). Whilst there was a moderate correlation between the two tracers, there were distinct differences in the pattern and distribution of uptake suggesting a differential detection of macrophage glycolytic and phagocytic activity respectively. These studies provide novel insights into vascular biological processes involved in the initiation, progression and rupture of atherosclerotic plaques and aortic aneurysms. Future longitudinal studies are needed to establish whether these techniques have a role in improving the clinical management and treatment of patients with coronary artery disease and aortic aneurysms.

No description available.

Image registration is a useful technique to measure the change between two or more images. Lung CT image registration is widely used an non-invasive method to measure the lung function changes. Non-invasive lung function measurement accuracy highly depends on lung CT image registration accuracy. Improving the registration accuracy is an important issue. In this thesis, we propose incorporating information of the anatomical structure of the lung (fissures) as an additional cost function of the lung CT image registration. The intensity-based similarity measurement method (sum of the squared tissue volume differences) is also used to complement lung tissue information matching. However, since fissures are hard to segment, a sheet-likeness filter is applied to detect fissure-like structures. Sheet-likeness is used as an additional cost function of the intensity-based registration. The registration accuracy is verified by the visual assessment and landmark error measurement. The landmark error measurement can show an improvement of the proposed algorithm.

Pulmonary embolism (PE) is a severe frequent disease with lack of specific symptoms and represents a major diagnostic challenge. In the past few years, single-slice spiral CT angiography has gained acceptance as a minimally invasive method of evaluating patients with suspicion of PE. The main limitation of single-slice spiral CT resides in the poor detection of subsegmental or more distal PE. This limited detection is not explained by an insufficient vascular distension during spiral CT acquisition but probably by an insufficient spatial resolution. Moreover, in some situations spiral CT is penalized by pulmonary angiography which is an imperfect gold standard. Today Multislice CT can acquire 2 up to 64 slices in a single rotation with isotropic resolution. This technique can cover the entire chest in 1-mm slice thickness or less, in one short breath-hold and allows a better analysis of peripheral pulmonary arteries with a better depiction of sub-segmental and peripheral clots. It also reduces or eliminates artefacts produced by patient movement and decreases the x-ray tube heating that can constrain singleslice scanning parameters. Acquisition of the lower extremities can be performed after chest CT, allowing detection of deep vein thrombosis and one stop shopping of the venous thromboembolic disease. The diagnostic accuracy of multislice CT is probably similar or superior to pulmonary angiography with an inferior delivered radiation dose, a better detection of alternative diagnoses and a continuous decrease of contrast medium injected. Last refinements in CT technology opens new frontiers for a functional approach of PE and predict its prognosis. For all the above-mentioned reasons, it seems obvious that multislice CT will definitively replace pulmonary angiography for diagnostic purposes and will represent a superb tool to better understand the physiopathology of this frequent and potentially life-threatening disorder.

X-ray computed tomography (CT) is a medical imaging framework. It takes measured projections of X-rays through two-dimensional cross-sections of an object from multiple angles and incorporates algorithms in building a sequence of two-dimensional reconstructions of the interior structure. This thesis comprises a review of the different types of algebraic algorithms used in X-ray CT. Using simulated test data, I evaluate the viability of algorithmic alternatives that could potentially reduce overexposure to radiation, as this is seen as a major health concern and the limiting factor in the advancement of CT [36, 34]. Most of the current evaluations in the literature [31, 39, 11] deal with low-resolution reconstructions and the results are impressive, however, modern CT applications demand very high-resolution imaging. Consequently, I selected ve of the fundamental algebraic reconstruction algorithms (ART, SART, Cimmino's Method, CAV, DROP) for extensive testing and the results are reported in this thesis. The quantitative numerical results obtained in this study, con rm the qualitative suggestion that algebraic techniques are not yet adequate for practical use. However, as algebraic techniques can actually produce an image from corrupt and/or missing data, I conclude that further re nement of algebraic techniques may ultimately lead to a breakthrough in CT. / UOIT

Positron Emission Tomography (PET) plays a very important role in the field of drugdevelopment already in the preclinical phase. This is done by using positron labeled molecules for different approaches/methodologies such as cell analysis, frozen section autoradiography, homogenate binding, organ distribution and at the end in vivo small-animal PET imaging. The technique is also used for integrated animal studies in which both functional information from PET or Single Photon Emission Tomography (SPECT) and structural information from Computed Tomography (CT) are integrated. However, significant improvements in technical aspects of the animal scanner such as resolution (under 1 mm), high sensitivity and ease of the operational procedures have affected the usage of these types of imaging. This study aims to test the technical and operational performance of the FLEX Triumph preclinical PET/SPECT/CT imaging system. Spatial resolution, sensitivity and partial volume effects have been the parameters in focus but a performance comparison between different isotopes and an in vivo mouse study has also been performed. The results show that the Triumph is capable of producing high quality images for all modalities and also high quality PET/CT fusions.

Bakgrund: Stroke är ett snabbt påkommande neurologiska bortfallssymtom med eller utan medvetandessänkning. Sedan införandet av multidetektor CT med kortare undersökningstider har CT blivit en lämplig metod för att utreda akut strokefall. Perfusions CT utförs med intravenös kontrast och tekniken kartlägger det cerebrala blodflödet och den cerebrala blodvolymen. Syfte: Syftet med den här studien är att se hur användbar Perfusions CT kan vara när det gäller misstänkt ischemisk stroke och trombolysbehandling. Metod: Studien är en litteraturstudie där två olika sökningar genomfördes i databaserna Pubmed och Medline. Till resultatet valdes åtta stycken artiklar ut efter att det kontrollerats att de blivit peer reviewed och var relevanta för studiens syfte. De sökord som användes var Perfusion CT, thrombolytic och Ischemic stroke. Kriterierna för artiklarna var att de skulle vara engelskspråkiga studier som publicerats mellan åren 2007 och 2012 och även vara humanförsök. Resultat: Resultatet visar att Perfusions datortomografi (PCT) guidad trombolys är patientsäker och två av de artiklar som inkluderas i studien visar att PCT är signifikant bättre än datortomografi när det gäller att identifiera tidig stroke tecken. Vidare så visade det sig att patienter med större mismatch områden på PCT har en större chans att få ett gynnsamt utfall.  Konklusion: Resultatet i den här uppsatsen visar att PCT är en användbar teknik när det gäller att utvärdera strokepatienter inför en möjlig trombolysbehandling. Men att det behöver bedrivas fler studier för att avgöra hur användbar tekniken är för detta syfte.