Alzheimer's disease (AD) is one of the top 10 leading causes of death in the US; it debilitates memory and impairs cognition. The current core clinical criteria for diagnosis of AD are based on functional deficits and cognitive impairments that do not include the advanced imaging techniques or cerebrospinal fluid analysis; the final confirmation of the disease is only possible at the time of autopsy when neurofibrillary tangles and beta-amyloids are present in a brain tissue examination. The distributions of these particular pathogens (neurofibrillary tangles and beta-amyloids) follow a pattern that is useful to identify different stages of AD at the time of the autopsy by looking at the presence of pathogens in the areas of the brain. The pathogens are first seen in entorhinal/perirhinal cortex, and then spread to hippocampus cornu ammonis subfields, followed by association cortex and finally the rest of the brain. This disease progression is standard and described in NIA-RI guidelines. In the last decades, with the introduction of advanced imaging techniques in research settings, many in vivo based research methods have been focusing on the volumetric measurements of the hippocampus and its subfields in MRI images and using them as additional information for early diagnosis of AD. While the hippocampal volume provides excellent diagnostic aid, it doesn't address both the pathogens associated with AD and the progression of the pathogens within the different subregions of the hippocampus. The hippocampus formation is a complex circuit that spans the temporal lobes and found to have distinctive subregions. These subregions are subject to different influence by AD at different stages. Since the disease progression as seen in pathogen distributions follows a pattern, studying the pattern of the regional changes will allow us to predict which stage the disease is at. These pathological shifts in regions of the brain are studied extensively in ex vivo MRI as well as during autopsy but not in in vivo MRI. Considering that the brain areas with neurofibrillary tangles and beta-amyloids show hypointensity (PD-weighted) and hyperintensity voxels (T2-weighted) in the MRI images, we suggest an in vivo study using normalized MRI images taken from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. We analyze the pattern of changes in the hippocampal region using a volume-based method in normalized T1-weighted MRI and an intensity-based analysis in normalized PD-weighted MRI. We use the volume-based method to calculate the changes in the volume of each of the hippocampus subfields. For the intensity-based method, we count the number of hypointensity (intensity value < 125) voxel combinations from the Gray-Level Co-occurrence Matrix (GLCM); a normalized MRI images are used inorder to minimize intensity variation. We then use the data (volume and intensity changes) to construct decision trees which classify the MRI images into three categories: normal control (NC), mild cognitive impairment (MCI) and AD. We have found that the volume-based decision trees detect AD MRI images with an accuracy of 75 % but failed to detect NC and MCI MRI images with the same level of accuracy. Whereas, with the intensity-based decision trees, we were able to classify MRI images into NC, MCI and AD categories each with an equally high level of accuracy (above 86 %). To find out how reliable the intensity-based method is in classifying MRI images, we introduced noises to our images. The addition of noises forced some adjustments in our decision trees. The accuracy of decision tree classification decreased in the presence of noises. However, even in the presence of the additional noises, we noticed that the intensity-based method outperforms volume-based method. The classification of MRI images improves when both measures (intensity-based and volume-based) are used in constructing our decision trees. This study has demonstrated that the inclusion of the intensity measurements of PD-weighted MRI images in AD studies may provide a more accurate way to model the natural progression of AD in vivo and contribute to the early diagnosis of AD. / A Dissertation submitted to the Department of Computer Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester 2017. / April 7, 2017. / ADNI, Alzheimer Disease, GLCM, Hippocampus Subfield, Intensity, Multimodel / Includes bibliographical references. / Xiuwen Liu, Professor Directing Dissertation; Samuel Grant, University Representative; Gary Tyson, Committee Member; Piyush Kumar, Committee Member.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Occupational Therapy Johannesburg, 2019 / Rugby, as a contact sport, has inherent risks of injury. Children and adolescents playing rugby at schoolboy level have a developing skeletal system and therefore injuries through this age of play may result in injuries to under-developed bones. This research study looked to identify whether the laws of rugby align to protect skeletal development of children and adolescents through law adaptations. Framework Analysis was used to develop a matrix which aligned the adapted laws of rugby with bone fusion ages. In future studies this can be used as a base for other areas of development and other sports. This matrix was further analysed to determine a severity rating scale and this scale identified some bones of the skull (occipital, sphenoid and zygomatic), upper limb (scapular, glenoid and clavicle) and lower limb (sacrum and pelvic girdle) as having a higher risk for severe injury. While these bones are at severe potential risk of injury it is important to note that only one measure of maturation was used and in future additional measures of maturation should be used. In conclusion, while the adapted laws of rugby do protect some bones of the developing skeletal system, they do not protect all of the developing bones of the skeletal system. The matrix could be used to guide future law makers in their endeavour of making the game of rugby safer for children and adolescents / MT 2020

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<p> Neutron radiography has the ability to differentiate between gas and liquid in twophase flow due both to the density difference and the high neutron scattering probability of hydrogen. Previous studies have used dynamic neutron radiography - in both real-time and high-speed - for air-water, steam-water and gas-liquid metal two-phase flow measurements. Radiography with thermal neutrons is straightforward and efficient as thermal neutrons are easier to detect with relatively higher efficiency and can be easily extracted from nuclear reactor beam ports.</p> <p> The quality of images obtained using neutron radiography and the imaging speed depend on the neutron beam intensity at the imaging plane. A high quality neutron beam, with thermal neutron intensity greater than 3.0xl06 n/cm2-s and a collimation ratio greater than 100 at the imaging plane, is required for effective dynamic neutron radiography up to 2000 frames per second.</p> <p> The primary objectives of this work are: (1) tu optimize a neutron radiography facility for dynamic neutron radiography applications and (2) to investigate a new technique for three-dimensional neutron radiography using information obtained from neutron scattering. </p> <p> In this work, neutron transport analysis and experimental validation of a dynamic neutron radiography facility is studied with consideration of real-time and high-speed neutron radiography requirements. A beam port based dynamic neutron radiography facility, for a target thermal neutron flux of l.Oxl07 n/cm2-s, has been analyzed, constructed and experimentally verified at the McMaster Nuclear Reactor.</p> <p> The neutron source strength at the beam tube entrance is evaluated experimentally by measuring the thermal and fast neutron fluxes using copper activation flux-mapping technique. The development of different facility components, such as beam tube liner, gamma ray filter, beam shutter and biological shield, is achieved analytically using neutron attenuation and divergence theories. Monte-Carlo simulations (using MCNP-4B code) are conducted to confirm the neutron parameters along the beam path and at the imaging plane. Good agreement between the analytical and the numerical values for the thermal neutron flux at the imaging plane to within 5% has been achieved. The MCNP simulations show that neutron back scattering, due to the presence of the back-wall biological shielding and the beam catcher, have an insignificant effect on the thermal neutron flux at the imaging plane, however, the epithermal and fast neutron fluxes have increased by 4-11 %.</p> <p> Experimental results show that the thermal neutron flux is nearly uniform over an imaging area of 20.0-cm diameter. The thermal neutron fl11x ranges from 1.0x 107 - 1.26x10 7 n/ cm2 -s at a reactor operating power of 3. 0 MW. The measured value for the neutron-to-gamma ratio is 6.0x 105 n/cm2-μSv and the Cadmium-ratio is observed to be 1.22. These values promote real-time neutron radiography with relatively high neutron attenuating materials such as light water and high-speed neutron radiography with relatively low neutron attenuating materials such as heavy water and Freon type fluids with a minimal contrast degradation resulting from non-thermal neutron content of the beam.</p> <p> A dynamic neutron radiography system has been developed and modified to obtain less neutron damage to the low-light level video camera. The system is used to visualize air-water two-phase flow in a natural-circulation loop to examine the dynamic capabilities of the radiography facility. Measurements of bubble velocity, void fraction, and phase distribution are successfully made. Single frames (-33 ms) of neutron images were captured using the dynamic neutron radiography system for air-water two-phase flow. The system was able to resolve single bubbles interfaces with an image spatial resolution of approximately 0.44 mm.</p> <p> Thermal neutron detectors are placed at the periphery of the neutron beam to detect neutrons scattered by a non-flowing two-phase object placed on a turntable to simulate motion of the gas phase. The results show the potential ability to use neutron scattering technique to provide two-dimension neutron radiography with additional information to the third dimension.</p> / Thesis / Doctor of Philosophy (PhD)

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Yes / Increasing diagnostic capacity is a national priority to expedite the timeliness and appropriateness of patient treatment interventions. Imaging, encompassing a range of technologies including X-ray, Computer Tomography, Magnetic Resonance Imaging and ultrasound, is a key diagnostic service and central to decision making in most, if not all, disease pathways. However, imaging is an expensive discipline accounting for an estimated 3-5% of the annual NHS budget. As a result, it is imperative that we maximize service efficiency while optimizing patient outcomes.

No / Radiography aspires to be a research active profession, but there is limited information regarding the number of individuals with, or studying for, a doctoral award. This study aims to profile UK doctoral radiographers; including their chosen award, approach and employment status. This was a prospective cohort study utilising an electronic survey. No formal database of doctoral radiographers existed therefore a snowball sampling method was adopted. The study sample was radiographers (diagnostic and therapeutic) based in the UK who were registered with the Health and Care Professions Council (HCPC) and who held, or were studying for, a doctoral award. A total of 90 unique responses were received within the timescale. The respondents comprised 58 females (64.4%) and the majority were diagnostic radiographers (n = 71/90; 78.9%). The traditional PhD was the most common award, although increasing numbers were pursuing Education or Professional Doctorates. An overall increase in doctoral studies is observed over time, but was greatest amongst those working in academic institutions, with 63.3% of respondents (n = 57/90) working solely within a university, and a further 10% employed in a clinical–academic role (n = 9/90). This study has demonstrated that radiography is emerging as a research active profession, with increasing numbers of radiographers engaged in study at a doctoral level. This should provide a platform for the future development of academic and clinical research.

Yes / Within medical imaging variations in patient size can generate challenges, especially when selecting appropriate acquisition parameters. This experiment sought to evaluate the impact of increasing body part thickness on image quality (IQ) and effective dose (E) and identify optimum exposure parameters. Methods: An anthropomorphic pelvis phantom was imaged with additional layers (1e15 cm) of animal fat as a proxy for increasing body thickness. Acquisitions used the automatic exposure control (AEC), 100 cm source to image distance (SID) and a range of tube potentials (70e110 kVp). IQ was evaluated physically and perceptually. E was estimated using PCXMC software. Results: For all tube potentials, signal to noise ratio (SNR) and contrast to noise ratio (CNR) deceased as body part thickness increased. 70 kVp produced the highest SNR (46.6e22.6); CNR (42.8e17.6). Visual grading showed that the highest IQ scores were achieved using 70 and 75 kVp. As thickness increases, E increased exponentially (r ¼ 0.96; p < 0.001). Correlations were found between visual and physical IQ (SNR r ¼ 0.97, p < 0.001; CNR r ¼ 0.98, p < 0.001). Conclusion: To achieve an optimal IQ across the range of thicknesses, lower kVp settings were most effective. This is at variance with professional practice as there is a tendency for radiographers to increase kVp as thickness increases. Dose reductions were experienced at higher kVp settings and are a valid method for optimisation when imaging larger patients. / Hashemite University in Jordan, College of Radiographers Industry Partnership (CoRIPS)