Accurate attenuation correction is essential for quantitative positron emission tomography. Typically, this correction is based on a coincidence transmission measurement using an external source of positron emitter, which is positioned close to the detectors. This technique suffers from poor statistical quality and high dead time losses, especially with a high transmission source strength. We have proposed and tested the use of single photon transmission measurement with a rotating rod source, to measure the attenuation correction factors (ACFs). The singles projections are resampled into the coincidence geometry using the detector positions and the r,)d source location. A nonparalyzable dead time correction algorithm was developed for the block detectors used in the McMaster PET scanner. Transaxial resolution is approximately 6 mm, which is comparable to emission scanning performance. Axial resolution is about 25 mm, with only crude source collimation. ACFs are underestimated by approximately 10% due to increased crossplane scatter, compared to coincidence transmission scanning. Effective source collimation is necessary to obtain suitable axial resolution and improved accuracy. The response of the correction factors to object density is linear to within 15%, when comparing singles transmission measurement to current coincidence transmission measurement. The major advantage of using singles transmission measurement IS a dramatically increased count rate. A factor of seven increase in count rate over coincidence scanning is possible with a 2 mCi transmission rod source. There are no randoms counted in singles transmission scans, which makes the measured count rate nearly linearly proportional with source activity. Singles detector dead time is approximately 6% in the detectors opposite a 2 mCi rod source. Present hardware and software precludes the application of this technique in a clinical environment. We anticipate that real time acquisition of detector singles can reduce the transmission scanning time to under 2 minutes, and produce attenuation coefficient images with under 2% noise. This is a significant improvement compared to the current coincidence transmission technique. / Thesis / Master of Science (MS)

This study attempts to develop a method for absolute quantitation in Positron Emission Tomography. This includes the definition of the dimension and the position of a tumour in the brain as well as the evaluation of the amount of drug delivered to the tumour and to surrounding tissues in a pixel-by-pixel way, from the image. The defined objectives can be achieved using the calibrated FWHM values of the distribution of events in the tumour image, versus distance, to determine the dimension and the position of the tumour. The concentration activity in the tumour and the tumour-to-nontumour activity ratios can be obtained from the image, using a modified filter and the calibration of the tomograph. The colour scale of the image can be expressed in absolute units (μCi/ml) and the concentration activity can be evaluated in each pixel of the image or in each volume element of the body. / Thesis / Master of Science (MS)

No description available.

Americans spent approximately $47.7 billion on pet products and services in 2010, an increase of 4.8% over 2009, making the pet industry a market segment ripe with opportunity for entrepreneurial small business venture (American Pet Products Association, 2013). Small businesses invite innovation, create and provide new jobs, foster entrepreneurial spirit and creativity, and create competition that drives future business endeavors (Hillary, 2001). The pet dog industry is a salient example of entrepreneurial activity in which the pressures of business, economics, and learning coalesce. Because small businesses bolster about half of the private-sector economy and represent more than 99% of all business firms (Small Business Administration, 2013), it is useful for small business owners to learn and prosper as entrepreneurs. "Entrepreneurship is a learning process, and a theory of entrepreneurship requires a theory of learning" (Minniti, 2010, p. 9). However, there is still limited knowledge and understanding of the interaction between learning and entrepreneurship, and such a process remains one of the most neglected areas of entrepreneurial research and thus understanding (Deakins and Freel, 1999). This study explored entrepreneurial decision making by using the construct of David A. Kolb's Learning Style Inventory to examine an entrepreneurial operation in the pet dog-training industry. The researcher worked hand-in-hand with the entrepreneur in a collaborative partnership to explore the phenomenon using narrative inquiry research methods. A series of semi-structured interviews were used to collect and analyze stories and identify key considerations for learning style in relation to entrepreneurship. The results showed the entrepreneur's preferred learning style aligned with his expressed style and demonstrated a keen sense of operations awareness. Additionally, the entrepreneur had learned how to leverage his strengths over time while recognizing and compensating for his weaknesses. For a novice or someone with a desire to learn more about their own entrepreneurial inclinations, results from a learning style instrument could provide such understandings with helpful implications for small business ownership. Future studies could contribute to entrepreneurial research and add greater voice to the pet dog industry. / Ph. D.

En el Servicio de Daño Cerebral del Hospital Valencia al Mar de Valencia, hasta ahora, el daño funcional que tienen los pacientes que han sufrido un traumatismo craneoencefálico (TCE) se evaluaba de manera cualitativa a través de imágenes FDG-PET (Fluorodeoxyglucose Positron Emission Tomography). En este trabajo de tesis se propone utilizar técnicas de análisis basado en vóxel para poder evaluar las imágenes FDG-PET de manera cuantitativa, para ello se presenta una adaptación de la metodología morfometría basada en vóxel. El objetivo final de la evaluación cuantitativa de las imágenes es que ésta sirva de apoyo para el pronóstico sobre el grado de independencia de los pacientes. Primero se aplicaron las técnicas de análisis basado en vóxel a un único caso longitudinal, en el que se disponían de dos imágenes FDG-PET de un paciente que sufre una encefalitis herpética (primera imagen) y tiene una recaída un año después (segunda imagen). En este caso se realizó una sustracción de las imágenes volumétricas PET, que fue muy útil para poder relacionar las diferentes consecuencias de cada episodio. Esto también ayudó a confirmar la hipótesis de un fenómeno bi-fásico, en contra de la hipótesis progresiva/degenerativa. A continuación, se aplicaron las técnicas de análisis basado en vóxel a nivel de grupo para estudiar la relación entre el metabolismo talámico expresado en las imágenes FDG-PET y el estado neurológico para los diferentes grupos de pacientes que han sufrido un TCE. Esto permitió conocer que existen diferencias metabólicas entre los distintos estados neurológicos y que cuanto peor fuese el estado neurológico del paciente menor metabolismo talámico tenía. El proceso de recuperación de los pacientes que han sufrido un TCE atraviesa diferentes estados neurológicos comenzando por el estado de coma. A lo largo de este proceso el personal sanitario va realizando pruebas para ver en qué estado neurológico se encuentra el paciente y en función de éste poder / Lull Noguera, N. (2012). Técnicas de análisis basadas en voxel aplicadas a imágenes FDG-PET como apoyo en el diagnóstico de pacientes con traumatismo craneoencefálico [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16184

Yes / Non-invasive imaging methods are required to monitor the inflammatory content of atherosclerotic plaques. FEDAA1106 (N-(5-fluoro-2-phenoxyphenyl)-N-(2-(2-fluoroethoxy)-5- methoxybenzyl) acetamide) is a selective ligand for TSPO-18kDa (also known as peripheral benzodiazepine receptor), which is expressed by activated macrophages. We compared 18F- FEDAA1106 and 18F-FDG (a marker of glucose metabolism) for PET imaging of vascular inflammation. This was tested using a murine model where focal inflammation was induced in the carotid artery via placement of a constrictive cuff. Immunostaining revealed CD68-positive cells (macrophages) at a disturbed flow site located downstream from the cuff. Dynamic PET imaging using 18F-FEDAA1106 or 18F-FDG was registered to anatomical data generated by CT/CT angiography. Standardized uptake values (SUV) were significantly increased at cuffed compared to contralateral arteries using either 18F-FEDAA1106 (p<0.01) or FDG (p<0.05). However, the 18F-FEDAA1106 signal was significantly higher at the inflamed disturbed flow region compared to the non-inflamed uniform flow regions, whereas differences in FDG uptake were less distinct. We conclude that 18F-FEDAA1106 can be used in vivo for detection of vascular inflammation. Moreover, the signal pattern of 18F-FEDAA1106 correlated with vascular inflammation more specifically than FDG uptake. / : This study was funded by the British Heart Foundation and through a grant from the Swiss National Science Foundation (310030_143343/1 to B.R.K.)

Yes / Fluorine substitution is an established tool in medicinal chemistry to favourably alter the molecular properties of a lead compound of interest. However, gaps still exist in the library of synthetic methods for accessing certain fluorine-substituted motifs. One such area is the fluoromethyl group, particularly when required in a fluoroalkylating capacity. The cold fluorination of methylene ditosylate is under evaluated in the literature, often proceeding with low yields or harsh conditions. This report describes a novel microwave method for the rapid nucleophilic fluorination of methylene ditosylate using inexpensive reagents in good isolated yield (65%).

The purpose of this study was to evaluate attachment of people to their pets as compared to their human relationships. Specifically, this research was meant to discover if pet attachment was a more secure attachment than human-human attachment. One hundred and ninety-four students from an Introductory Psychology class at the University of Central Florida completed a survey regarding pet and human attachment. The results are discussed.

OBJECTIVE: To explore the effect of pet ownership (PO) on the oral health of older adults. METHODS: NHANES data 2005-06 was analyzed (logistic/linear regression), restricted to aged 65 years and older. The outcomes of interest were the presence/absence of untreated dental caries, the presence/absence of dental restorations, and mean number of teeth. The primary independent variable was PO status within the past year. Potential confounders included demographic data (age, gender, race, marital status, poverty income ratio, education), smoking status, depression, physical activities, and mean sugar intake, taking into account NHANES complex sampling. RESULTS: Individuals aged 65-69 were more likely to own pets than those older than 70 years, with dogs being the most popular pet (62%) followed by cats (31%). After adjusting for potential confounders, there was no association between pet ownership in seniors and the outcomes of interest. Non-Hispanic blacks reported the highest tooth loss (-6.42 teeth) among the racial groups and were 40% less likely to have a dental restoration. In the unadjusted model Mexican Americans have 2.83 times the odds of untreated dental caries compared to Non-Hispanic whites, while current smokers had 7 fewer teeth than those who never smoked. CONCLUSIONS: Pet ownership was not associated with improved oral health for older adults. Despite the lack of oral health protection, pet ownership provides companionship, reduces loneliness, and increases socialization among older adults.

This thesis is a study of architecture on how to improve the life of homeless animals through strengthening the relationship between us, humans and the animals we live among. There are millions of shelter animals being killed every year which is both dreadful and expensive. This number can be decreased greatly if people acted more responsibly towards the creatures they have domesticated. It is true that most people enjoy taking care of animals, they usually feel a strong emotional connection with them, specially those who share their homes with their pets. The problem is that many find the animal shelters a depressing place filled with sick unwanted animals. How can we, design professionals, encourage people to interact more with animal shelters? How can the design affect both physical and emotional health of these animals? Can architecture raise awareness about the creatures in our urban civilization? This project explores a few design approaches that can teach people about shelters and urban animals and how physically different we are from them. The building is also a study of an animal shelter as a system that can improve their day-to-day life to become healthier and happier. It is proposed that these architectural changes would aid the adoption rate as well as creating a happier pet and owner. / Master of Architecture / Each year millions of adoptable animals are killed in shelters simply because people are not responsible enough to take action. People have always loved animals and have domesticated them from thousands of years ago. This makes us responsible for their lives and their well being. The general understanding is that animal shelters are very sad depressing places filled with sick unwanted animals. This keeps people away from animal shelters. People usually show affection to animals when they are interacting with them. How can the housing for these unwanted animals be a desirable place where people want to visit? How can it be the place where our physical differences are celebrated so we learn about their different needs? This project explores different ways to encourage interaction between humans and animals as well as to create a wholesome place for the animals to live. Through the beautiful experience of the shelter, these design approaches would motivate people to adopt healthy and happy animals.