Thesis submitted in full compliance with the requirements for the Masters in Technology Degree: Radiography, Durban University of Technology, 2006. / This study aimed at determining and evaluating the prevalence of gallstones in the Black population of District 28 (D28) in relation to age, gender, diet and body mass index (BMI) in order to identify people at high risk and advise them so that they can avoid the complications and decrease the morbidity rate. Blacks are thought to have increased prevalence of gallstones but there has been no systematic evaluation of its prevalence in D28. METHODS AND MATERIALS 389 Black people from D28 were selected from referrals (for many different radiological examinations) coming to the X-ray and ultrasound departments. Some of the respondents were staff members who also met the selection criteria for the study. An interview was conducted at Ngwelezane hospital using a structured questionnaire on health, social and diet history of the respondents. All information was entered into the data sheet. All respondents were then scanned using Mid-range ultrasound machines to establish the presence of gallstones and this information was thereafter documented on the data sheet. SPSS version 11.5 (SPSS Inc, Chicago, III) was used for data analysis. Prevalence and 95% confidence intervals were calculated using the Epitable module of Epi Info version 6.04 (CDC, 2001). Pearson's Chi square tests were used to assess associations between categorical variables and gall stones. Logistic regression analysis was applied to assess the independent effects of multiple risk factors on the development of gallstones. Backwards elimination method based on likelihood ratios was used with entry and exit probabilities set at 0.05 and 0.1 respectively / M

Globally there is a lack of radiologists, which results in unreported radiographic examinations, or a delay in reporting on radiographic images even in emergency situations. In order to mitigate and alleviate the situation, and optimise the utilisation of radiographers a red dot system was introduced in the United Kingdom, which later aided in the transformation of the role of radiographers in terms of formal reporting of various radiographic examinations. Although there is a shortage of medical practitioners and radiologists in South Africa the extended role of radiographers has not been yet realised for radiographers. At present, radiographers and medical practitioners work in collaboration to interpret and report on radiographic examinations informally, to facilitate effective and efficient patient management, but this is done illegally because the regulations defining the scope of the profession of radiography does not allow for such practice, putting radiographers and organisations at risk of litigation. In order to gain an in-depth knowledge of the phenomena, to enable the researcher to provide recommendations to the Professional Board of Radiography and Clinical Technology (PBRCT) of the Health Professions Council of South Africa (HPCSA), a qualitative, exploratory, descriptive, and contextual research study was undertaken. Radiographers and medical practitioners were interviewed in order to elicit rich descriptions of their experiences regarding reporting of trauma related radiographic images in the after-hours trauma units. Data were gathered using in-depth semi-structured interviews, and the data were analysed using kesch’s method of thematic synthesis. Three themes emerged from the data, namely the challenges radiographers and medical practitioners face in the after-hours trauma units respectively, with regards to reporting of trauma related adiographs, and suggestions were proposed to optimize the participation of radiographers with regard to trauma related radiographs in these units. A thick description and literature control was done using quotes from participants. Measures to ensure trustworthiness and ethical research practices were also implemented. Thereafter, recommendations were put forward for the PBRCT of the HPCSA, using current literature and inferences made from the findings of the study.

Atualmente observa-se que as queixas de afecção física mais comuns do aparelho locomotor na clínica médica e do esporte, entre adultos jovens e adolescentes ativos, estão relacionadas ao joelho, sendo o sintoma de dor femoropatelar, a mais freqüente. Porém, essa condição é uma incógnita, para os especialistas em joelho, quando se tenta definir uma causa específica e de consenso. Como forma de tentar contribuir na elucidação desse problema resolveu-se executar este trabalho investigativo, buscando-se encontrar diferenças clínicas e biomecânicas entre indivíduos do sexo feminino, com e sem o referido sintoma, com idade entre 15 e 20 anos. Foram avaliadas 23 jovens com dor femoropatelar bilateral, sem afecção conhecida presente e 20 sem sintoma (46 joelhos sintomáticos e 40 assintomáticos). Todas foram submetidas a exames radiográficos (incidências: antero-posterior, perfil e axial), onde se verificou o alinhamento femorotibial, a altura patelar, o ângulo do sulco, o ângulo de congruência, e o ângulo femoropatelar lateral. Também se mensurou a retração dos isquiotibiais e o ângulo Q em exame clínico e, os indivíduos da pesquisa ainda se submeteram a avaliação da força, por dinamometria isocinética, dos grupos musculares extensores e flexores do joelho e do quadril, além dos rotadores mediais e laterais e os adutores e abdutores do quadril. Após análise dos resultados, pode ser observado que as diferenças, estatisticamente significativas, entre os grupos estudados, foram quanto ao alinhamento do membro inferior, com o ângulo Q apresentando um p < 0,001, o ângulo femoropatelar lateral com um p = 0,006, o ângulo do sulco com o p < 0,001, o ângulo de congruência com o p = 0,027 e, o único parâmetro diferente estatisticamente na dinamometria isocinética, foi o ângulo do pico de torque da extensão do quadril, com um p = 0,03. De acordo com os resultados da comparação entre o grupo sintomático e o assintomático, observa-se que há uma relação importante do mau alinhamento da articulação do joelho com a sintomatologia estudada, porém não pode ser apontado um ou outro ângulo como o mais importante para o surgimento da dor, ou talvez ainda possa ser dito que estes desalinhamentos predispõem o joelho ao sintoma, mas talvez não sejam as causas primárias da afecção. Ficou demonstrado que o aumento do ângulo Q e o encurtamento dos isquiotibiais não são causas de dor femoropatelar. Foi verificado que indivíduos com e sem o sintoma não apresentam diferença quanto a força muscular de músculos envolvidos na ação do quadril e do joelho. O ângulo femoropatelar lateral apresentou média maior no grupo assintomático, enquanto que a média do ângulo do sulco, no mesmo grupo, foi menor. Já o ângulo de congruência apresentou média positiva no grupo assintomático e negativa no grupo com dor, mostrando que a patela do grupo com dor, tem seu ápice mais medializado que a do grupo controle / Presently it has been observed that the most common physical affection in the locomotor system in medical and sportive clinic, among active young adults and adolescents are related to the knee, being femoropatellar pain symptom the most frequent. Although, this condition is unknown for those who are specialists in knee when they try to identify a specific cause and an agreement. As a way of trying to contribute for the elucidation of this problem, it has been decided to execute this investigative study trying to find clinic, radiographic and isokinetic differences among female individuals, with and without the above mentioned symptom, between 15 and 20 years old. 23 young females with bilateral femoropatellar pain were analyzed, with unknown affection, and 20 without symptoms (46 symptomatic knees and 40 asymptomatic). All of them were submitted to radiographic exams (anteroposterior, profile and axial incidences), were it was verified the femorotibial alignment, the patellar height, the groove angle, the congruence angle and the femoropatellar lateral angle. It was also measured the hamstring shortness and Q angle in clinic exam and, the individuals of this study were submitted to strength evaluation, by isokinetic dynamometry of the extensor and flexor muscles of knees and hips, besides hip medial and lateral rotators and the adducts and abducts. After analyzing the results, it can be observed that the statistically significant differences among studied groups were related to the inferior member alignment, with the Q angle presenting p value < 0,001, the femoropatellar lateral angle p value = 0,006, the groove angle p value < 0,001, the congruence angle p value = 0,027 and, the only one statistically different parameter in isokinetic dynamometry was the torque peak angle of hip extension with p value = 0,03. According to the results of comparison between symptomatic and asymptomatic groups there is an important relationship between bad alignment of the knee joint with the studied symptomatology, but it cannot be appointed one or another as the most important for the appearing of the pain, or maybe it still can be said that these disarrangements can predispose the knee to the symptom, but maybe they are not the primary causes of the affection. It was shown that the raise of the Q angle and the hamstring shortness are not the causes of femoropatellar pain. It was verified that individuals with or without the symptom do not show difference in relation to the muscular strength of the involved muscles in movement of the hip and knee. The femoropatellar lateral angle presented higher average in the asymptomatic group, while the average of the groove angle, in the same group, was smaller. Yet the congruence angle presented a positive average in the asymptomatic group and a negative average in the group with pain, showing that the patella in the group with pain has its apex more medially than the control group

Ngar, Yuen Kan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 157-159). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

"This study characterizes the image quality parameters of a clinical full-field digital mammography system at various x-ray spectral conditions. The energy of the incident x-ray beam, the spectral characteristics, and breast thickness impact the physical performance such as the detective quantum efficiency of the system, thereby affecting the overall performance. The modulation transfer function, noise power spectrum were measured without the anti-scatter grid, and the detective quantum efficiency was calculated for different incident x-ray conditions. Detective quantum efficiency was also calculated with the anti-scatter grid placed above the detector to study its impact. Results indicate a substantial drop in the detective quantum efficiency with the anti-scatter grid under certain conditions. It was also determined that detective quantum efficiency decreases as x-ray beam hardening is increased. A spatial frequency-dependent cascaded liner systems model was developed to predict the detective quantum efficiency of the system for different target-filter combinations. This theoretical model is based upon a serial cascade approach in which the system is conceptually divided into a number of discrete stages. Each stage represents a physical process having intrinsic signal and noise transfer properties. A match between the predicted data and the experimental detective quantum efficiency data confirmed the validity of the model. Contrast-detail performance, a widely used quality control tool to assess clinical imaging systems, for the clinical full-field digital mammography was studied using a commercially available CDMAM phantom to learn the effects of Joint Photographic Experts Group 2000 (JPEG2000) compression technique on detectability. A 4-alternative forced choice experiment was conducted. The images were compressed at three different compression ratios (10:1, 20:1 and 30:1). From the contrast-detail curves generated from the observer data at 50% and 75% threshold levels, it was concluded that uncompressed images exhibit lower (better) contrast-detail characteristics than compressed images but a certain limit to compression, without substantial loss of visual quality, can be used."

O exame radiográfico interproximal vem sendo o método mais comumente utilizado como auxiliar no diagnóstico da presença e extensão de lesões de cárie nas superfícies proximais de dentes posteriores e, muitas vezes, funciona como base para a tomada de decisão restauradora. Este estudo tem o objetivo de analisar a possibilidade de previsão de cavitação clínica ou ausência desta nas superfícies proximais em contato de dentes posteriores permanentes e decíduos, de acordo com a extensão da imagem em radiografias interproximais. Para tanto, uma revisão sistemática da literatura foi realizada. Após a formulação da questão de pesquisa estruturada, dois revisores realizaram uma busca nas bases eletrônicas das bibliotecas Medline (PubMed), Embase, LILACS, Scopus e Cochrane. Apenas estudos clínicos foram incluídos. Não houve restrição de idioma ou de data de publicação, sendo incluídos estudos publicados até o mês de abril de 2016. Também foi realizada busca manual nas referências dos artigos selecionados e nas edições da revista Caries Research. Ao final, foram selecionados 11 estudos, os quais apresentaram avaliação da imagem radiográfica e relação com a condição clínica através de diferentes métodos: exame visual associado ou não à separação dentária, seguida ou não de moldagem, ou avaliação após abertura de cavidade em procedimento restaurador com ou sem fotografias. Os resultados da análise qualitativa dos dados mostram que, quando a lesão de cárie apresenta extensão de imagem radiográfica em metade externa de esmalte, a maior probabilidade é de que não haja presença de cavitação clínica; quando a imagem estende-se além da metade ou 2/3 interno de dentina, provavelmente existe cavitação. A discordância mais evidente entre os estudos ocorre quando a imagem radiolúcida atinge a metade interna de esmalte ou metade/terço externo da dentina. Quando na presença deste tipo de imagem radiográfica, o afastamento dentário e inspeção visual estão indicados para a tomada de decisão diagnóstica e consequente decisão de intervenção. Além disso, os fatores que podem influenciar na probabilidade da presença de cavitação clínica devem ser considerados, como padronização da técnica radiográfica, atividade e taxa de progressão de cárie, diferenças populacionais e idade do paciente. / Bitewing radiographic examination has been the most commonly used method to assist the diagnosis of the presence and extension of caries lesions on the proximal surfaces of posterior teeth, and often serves as a basis for restorative decision making. This study aims to analyze the possibility of prediction of clinical cavitation or absence of it in the proximal surfaces of permanent and deciduous posterior teeth, according to the extension of the image in bitewing radiographs. A systematic review of the literature was performed. After formulating the structured research question, two reviewers searched the electronic databases of the Medline (PubMed), Embase, LILACS, Scopus and Cochrane libraries. Handsearch was also carried out on the references of the selected articles and in the editions of the journal Caries Research. Only clinical studies were included. There was no restriction on language or date of publication, included studies published until the month of april of 2016. Eleven studies were selected, which presented an evaluation of the radiographic image and relation with the clinical condition through different methods: visual examination associated or not with dental separation (followed or not by impression) or evaluation during drilling with or without photographs. A qualitative analysis of the data show that when the caries lesion presents radiographic image in the outer half of the enamel, the greatest probability is that there is no clinical cavitation; when the image extends beyond to the inner half or inner 2/3 of dentine, there is a great chance of cavitation. The most evident discordance among studies occurs when the radiolucent image reaches the cut-off point of the inner half of the enamel or external half / third of the dentin. When in the presence of this type of radiographic image, the dental separation and visual inspection are indicated for the diagnostic decision making and consequent intervention decision. In addition, factors that may influence the probability of the presence of clinical cavitation should also be considered, such as standardization of the radiographic technique, activity and rate of caries progression, population differences and age of the patient.

Although there are now many theories describing empirical relationships between strength properties of bone and various explanatory variables, the need for improved non-invasive diagnostic techniques to assess bone fragility is of core importance in clinical problems such as osteoporosis. The aim of this thesis was to develop non-invasive radiological methods to assess trabecular bone architecture. Measures of structural anisotropy and bone structure from X-ray or radiological projections have been developed. The first measure, the projected mean intercept length (PMIL), allows extraction of the total bone surface (BS/TV) and the mean intercept length (MIL) from projections of trabecular structure. The second measure, the line projection deviation (LPD), is a technique that quantifies the preferential alignment of trabecular bone from projections of the trabecular structure. Hence, in combination, the PMIL and LPD allow non-invasive extraction of BS/TV and more detailed preferential alignment from projections of the trabecular structure. In this thesis the PMIL and LPD are introduced and their properties explored. The PMIL and LPD are used to examine the anisotropy and architectural properties of a number of human vertebral body trabecular bone samples. When used in combination with clinical densitometry, these measures improve explanation of the variance in strength, elastic modulus and toughness of vertebral body trabecular bone samples by up to 40% when compared to densitometric values alone. While µCT can provide the information needed to access trabecular architecture, it cannot be used in clinical settings since its high radiation dose makes it only applicable to small objects ex-vivo. At present, clinically available CT does not provide sufficient resolution to resolve trabecular structures. Thus, the methods described in this thesis will allow estimates of structural parameters from plain X-rays, providing for the first time, the possibility of clinical use of such estimates. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1311218 / Thesis (Ph.D.) -- School of Medical Sciences, 2008

The National Council of Radiation Protection and Measurements Report No. 49, originally issued on September 15, 1976, has been the primary design guide for diagnostic x-ray structural shielding in the United States. To further protect the public from various areas of medical radiation exposure, NCRP issued Report 116 in 1987 to decrease the public exposure limits. These new limits used in conjunction with NCRP 49 to determine shielding requirements for diagnostic radiological rooms can be shown to over-shield based on current technologies and protocols. This paper explores the NCRP conservative assumptions that physicists specifying barrier requirements for diagnostic x-ray facilities normally utilize. These evaluated assumptions, which are incorporated in the methodology and attenuation data presented in NCRP Report 49 formulas, include relatively high single kVp's, a "one size fits all" workload default, and the lack of attenuation factors by the patient, the wall, and the film. In essence, an analysis of the conservative nature of NCRP 49 is demonstrated. An example of Primary and Secondary Shielding Methodology utilizing NCRP 49 and NCRP 116 dose limits is provided as well as the cost factors associated with the results. These examples are further evaluated using a Monte Carlo software program. In addition, an analysis of actual current radiographic conditions in an imaging room is performed. This is done to determine first, the actual mA utilized for specific exams; secondly, the actual mA-min weekly workload; and thirdly, the tangible exams performed per week in small and large medical facilities. Based on the information and analysis presented, this paper concludes that the formulas for NCRP 49 and NCRP 116 need to be reexamined. Furthermore, this paper also demonstrates once again that NCRP 49, utilizing NCRP 116 dose limits is extremely conservative. / Graduation date: 2004

No description available.

Neutron radiography is a non-destructive analysis tool that complements X-ray transmission radiography. The use of neutrons provides the ability to image the interior of an object that has a metal core of steel or lead that would shield the interior from X-ray inspection. Neutron tomography is the use of a set of images of a single sample taken at various angles to produce a three dimensional rendition of the sample that greatly increases the effectiveness of neutron radiography as a non-destructive testing tool. A neutron radiography and tomography system has been built at the 1.1 MW TRIGA Mark II nuclear research reactor at The University of Texas at Austin in the Nuclear Engineering Teaching Lab. The Texas Neutron Imaging Facility is located on beam port five of the reactor and is housed in a shielding cave made of concrete to minimize radiation dose to users. The system itself integrates a sample positioning system and neutron sensitive camera through the use of a control code written in National Instruments Labview software. The code was written to increase the efficiency of the imaging process and to provide flexibility in the system. Precise sample positioning and timing of image acquisition provided by the code allows for the collection of data that can be used in computed tomography. The system has produced results in the form of radiographs and 3-D reconstructions of sample objects. / text