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The objectives of this research were to evaluate non-invasive measures of bone mineral content (BMC) and bone mineral density (BMD) as rapid, on-farm tools to assess phosphorus (P) status in dairy cows. In addition, the effects of parity and stage of lactation on measures of BMC of the fused 3rd and 4th metacarpal bone and of caudal vertebrae 14 and 15 were assessed. The caudal vertebrae and right front metacarpal (sample pairs) were excised from 107 Holstein cull cows following slaughter. Parity, age, and days in milk (DIM) of the donor animal were obtained for 43 pairs of samples. Samples were grouped by parity (1, 2, 3, and >4) and stage of lactation (Stage 1 = < 90 DIM, Stage 2 = > 90 and < 150 DIM, Stage 3 = >150 and < 250 DIM and Stage 4 = > 250 DIM). Samples were analyzed for BMC and BMD with dual energy X-ray absorptiometry (DXA), BMC with radiographic photometry (RP), breaking strength with mechanical methods, and mineral content with chemical procedures. Estimates of BMC obtained with RP and DXA were poorly related to chemical measures of actual BMC and to measures of breaking strength. In caudal vertebrae 14 and 15, increasing stage of lactation decreased energy to peak load with the lowest values observed in late lactation. Stage of lactation had no effect on BMC measured chemically in the caudal vertebrae or metacarpal. Parity did not affect breaking strength of the metacarpal or caudal vertebrae or total ash or P content of any bone. Results indicated that imaging techniques are not useful measures of BMC in mature dairy cattle. / Master of Science

L'un des principaux défis de l'interprétation radiographique réside dans la compréhension de l’anatomie radiographique, laquelle est intrinsèquement liée à la disposition tridimensionnelle des structures anatomiques et à l’impact du positionnement du tube radiogène vis-à-vis de ces structures lors de l'acquisition de l'image. Traditionnellement, des radiographies obtenues selon des projections standard sont employées pour enseigner l'anatomie radiographique en médecine vétérinaire. La tomodensitométrie − ou communément appelée CT (Computed Tomography) − partage plusieurs des caractéristiques de la radiographie en ce qui a trait à la génération des images. À l’aide d'un plug-in spécialement développé (ORS Visual ©), la matrice contenant les images CT est déformée pour reproduire les effets géométriques propres au positionnement du tube et du détecteur vis-à-vis du patient radiographié, tout particulièrement les effets de magnification et de distorsion. Afin d'évaluer le rendu des images simulées, différentes régions corporelles ont été imagées au CT chez deux chiens, un chat et un cheval, avant d'être radiographiées suivant des protocoles d'examens standards. Pour valider le potentiel éducatif des simulations, dix radiologistes certifiés ont comparé à l'aveugle neuf séries d'images radiographiques simulées aux séries radiographiques standard. Plusieurs critères ont été évalués, soient le grade de visualisation des marqueurs anatomiques, le réalisme et la qualité radiographique des images, le positionnement du patient et le potentiel éducatif de celles-ci pour différents niveaux de formation vétérinaire. Les résultats généraux indiquent que les images radiographiques simulées à partir de ce modèle sont suffisamment représentatives de la réalité pour être employées dans l’enseignement de l’anatomie radiographique en médecine vétérinaire. / Understanding radiographic anatomy, which is intimately linked to the comprehension of tridimensional anatomy and the impact of patient, radiographic tube and x-ray detector positioning, represents a challenge for students. Traditionally, radiographs obtained under specific angles of projection have been used for teaching radiographic anatomy. Computed tomography (CT) shares several features with radiography with regard to image production. A plug-in was developed for a DICOM viewer (ORS visual ©) simulating radiographs using CT datasets. This plug-in distorts the CT image matrix to reproduce the magnification and distortion effects that take place in radiographs due to the variations in radiographic tube, patient and detector positioning and angulation. In order to test this model, specific body parts of two dogs, one cat and one horse were radiographed and CT-scanned. The CT datasets were used to generate a total of nine series of radiographic simulations that could be compared to corresponding standard radiographic projections. Ten board-certified veterinary radiologists blindly scored several parameters in these image series, including the visualization of specific anatomical landmarks, image realism and quality, patient positioning, and the educational potential for students and veterinarians of variable degree of veterinary training Overall results indicate that simulated radiographs are representative enough to be used to teach several concepts of image formation and radiographic anatomy in veterinary radiology.

L'un des principaux défis de l'interprétation radiographique réside dans la compréhension de l’anatomie radiographique, laquelle est intrinsèquement liée à la disposition tridimensionnelle des structures anatomiques et à l’impact du positionnement du tube radiogène vis-à-vis de ces structures lors de l'acquisition de l'image. Traditionnellement, des radiographies obtenues selon des projections standard sont employées pour enseigner l'anatomie radiographique en médecine vétérinaire. La tomodensitométrie − ou communément appelée CT (Computed Tomography) − partage plusieurs des caractéristiques de la radiographie en ce qui a trait à la génération des images. À l’aide d'un plug-in spécialement développé (ORS Visual ©), la matrice contenant les images CT est déformée pour reproduire les effets géométriques propres au positionnement du tube et du détecteur vis-à-vis du patient radiographié, tout particulièrement les effets de magnification et de distorsion. Afin d'évaluer le rendu des images simulées, différentes régions corporelles ont été imagées au CT chez deux chiens, un chat et un cheval, avant d'être radiographiées suivant des protocoles d'examens standards. Pour valider le potentiel éducatif des simulations, dix radiologistes certifiés ont comparé à l'aveugle neuf séries d'images radiographiques simulées aux séries radiographiques standard. Plusieurs critères ont été évalués, soient le grade de visualisation des marqueurs anatomiques, le réalisme et la qualité radiographique des images, le positionnement du patient et le potentiel éducatif de celles-ci pour différents niveaux de formation vétérinaire. Les résultats généraux indiquent que les images radiographiques simulées à partir de ce modèle sont suffisamment représentatives de la réalité pour être employées dans l’enseignement de l’anatomie radiographique en médecine vétérinaire. / Understanding radiographic anatomy, which is intimately linked to the comprehension of tridimensional anatomy and the impact of patient, radiographic tube and x-ray detector positioning, represents a challenge for students. Traditionally, radiographs obtained under specific angles of projection have been used for teaching radiographic anatomy. Computed tomography (CT) shares several features with radiography with regard to image production. A plug-in was developed for a DICOM viewer (ORS visual ©) simulating radiographs using CT datasets. This plug-in distorts the CT image matrix to reproduce the magnification and distortion effects that take place in radiographs due to the variations in radiographic tube, patient and detector positioning and angulation. In order to test this model, specific body parts of two dogs, one cat and one horse were radiographed and CT-scanned. The CT datasets were used to generate a total of nine series of radiographic simulations that could be compared to corresponding standard radiographic projections. Ten board-certified veterinary radiologists blindly scored several parameters in these image series, including the visualization of specific anatomical landmarks, image realism and quality, patient positioning, and the educational potential for students and veterinarians of variable degree of veterinary training Overall results indicate that simulated radiographs are representative enough to be used to teach several concepts of image formation and radiographic anatomy in veterinary radiology.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 6 uppsatser. Includes bibliographical references.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 6 uppsatser.

This investigation dealt with locating and measuring x-ray absorption of radiographic images. The methods developed provide a fast, accurate, minicomputer control, for analysis of embedded objects. A PDP/8 computer system was interfaced with a Joyce Loebl 3CS Microdensitometer and a Leeds & Northrup Recorder. Proposed algorithms for bone location and data smoothing work on a twelve-bit minicomputer. Designs of a software control program and operational procedure are presented. The filter made wedge and limb scans monotonic from minima to maxima. It was tested for various convoluted intervals. Ability to resmooth the same data in multiple passes was tested. An interval size of fifteen works well in one pass.

Rectangular collimation is used in dentistry to reduce radiation by restricting the x-ray beam to approximately the size of a number 2 intraoral film (3.2X4.1 cm). However, this restricted beam size can lead to exposure errors. The aim of this study was to retrospectively evaluate the number of radiographs exposed and the presence of technical errors by the use of traditional circular or rectangular collimators during endodontic therapy on simulated teeth in manikins. A total of 1475 digital radiographs of 84 teeth exposed by 60 dental students were evaluated. Evaluation was done by a board certified endodontist, an endodontic resident, and a dental student. Analysis of the different raters showed no significant differences among the three. Radiographs were randomized and blindly renamed. Repeated-measures mixed-model ANOVA was used to compare the number of radiographs exposed using the different collimators. Although not statistically significant (P<.05), there were 15% more radiographs taken with the rectangular collimator when compared to the circular collimator. Using a repeated-measures logistic regression, there was a significant difference of the proportion of radiographs with cone cuts (P = .0003) taken with a rectangular collimator (59%) compared to radiographs taken with a circular collimator (19%). There was no significant evidence for a collimator difference when considering missed apex (P = .0986) or missed apex due to a cone cut (P = .0631). In order to expose high quality radiographs avoiding cone cuts, a traditional circular collimator may be indicated for use during endodontic therapy.

Resumo: A densitometria radiográfica é técnica que permite avaliar a densidade óssea, utilizando referências confeccionadas em material inerte (ex. alumínio), principalmente para investigação de alterações ósseas e doenças como a osteoporose. Para aumentar a precisão de técnica, alguns autores propõe o uso de equações matemáticas, como métodos dos mínimos quadrados, teorema de LaPlace e regra de Sarrus o que permitirá obter melhor ajuste da curva característica de absorção aos raios-X pelo objeto de estudo. O uso de tecnologias como Java, gnuplot, broffice calc, todas elas de código aberto, possibilitou-nos o desenvolvimento do software "ODR-ATA", capaz de analisar e processar imagens radiográficas digitais ou digitalizadas e calcular valores de densidade próximos aos valores do objeto em estudo. Atualmente diversas soluções pagas possuem suporte para realizar a densitometria radiográfica. O objetivo deste estudo foi desenvolver uma solução computacional de código livre, para cálculo da densidade óssea a partir da densitometria radiográfica. Para testar o software, foi realizado um experimento a partir de uma tomada radiográfica de uma escada de alumínio de valores conhecidos. Foram feitas 10 repetições e avaliados os degraus 4, 5, 6, 7 e 8 da escada de alumínio. Os resultados obtidos pelo "ODR-ATA" para os degraus 5, 6, 7 e 8 demonstraram uma precisão e exatidão de ordem de 3,64% e 3,63% respectivamente, atestando a validade e confiabilidadena utilização do software na obtenção da densidade óssea obtida pela densidade radiográfica. / Abstract: The radiographic densitometry is the technic that allows the evaluation of bone density, which uses references created in inert material (e.g. aluminium) especially to the investigation of bone modifications and illnesses such as osteoporosis. To increase technical precision some authors suggest the use of mathematical equations, such as the least squares method, Laplace's theorem, and the Rule of Sarrus allowing better results when achieving the adjustment of the curve that is characteristic of X-ray absorption by what is being studied. The usage of technologies such as Java, gnuplot, broffice calc, all of open code, allowed us to develop the software "ODR-ATA", which is capable of analyzing and processing digital radiographic images and of calculating values of density close to the values of the object under study. Recently, various paid solutions have the support to perform radiographic densitometry. The purpose of this study is to develop a computational solution of free code to calculate bone density starting from the radiographic densitometry. In order to test the software I performed an experiment that started with the radiography of an aluminum ladder of unknown values. I performed 10 repetitions and evaluated steps 4,5,6,7, and 8 of the aluminum ladder. The results I achieved with "ODR-ATA" for steps of number 5,6,7, and 8 show a precision of 3,64%% and 3,63% respectively, which attest for the validity and reliability of the software in the discovery of the bone density obtained through the radiographic densitometry / Orientador: Mário Jefferson Quirino Louzada / Banca: Luciana Del Pinoti Ciarlini / Banca: Gilberto Aparecido Coclete / Mestre

RESUMO O objetivo deste estudo foi obter as densidades radiográficas de diferentes filmes periapicais por meio de um programa computadorizado que utiliza a imagem equivalente em alumínio (alumínio-equivalente). Avaliaram-se os filmes Agfa Dentus M2 “Comfort", Kodak InSight, Kodak Ektaspeed Plus, Kodak Ultra-speed e Kodak D. Todos foram expostos aos raios X juntamente com um escalímetro de Alumínio, variando-se o tempo de exposição (0,1 a 1 segundo). Após a leitura das densidades radiográficas construiu-se um gráfico para compararmos as propriedades sensitométricas dos filmes. O filmes mais sensíveis foram o Agfa Dentus M2 “Comfort" e o Kodak InSight, e os menos sensíveis o Kodak Ultra-speed e o Kodak D. Os filmes Agfa Dentus M2 “Comfort" e Kodak InSight apresentaram os maiores contrastes. Os resultados obtidos por este método indicam que deve-se utilizar os filmes Agfa Dentus M2 “Comfort" e Kodak InSight para reduzir a dose de radiação recebida pelo paciente. / ABSTRACT The aim of this study was to obtain radiographic densities from different dental intraoral x-ray films through a software using aluminium-equivalent image. The densities had been measured in order to compare dental x-ray films in terms of speed, base plus fog, and contrast. Agfa Dentus M2 “Comfort", Kodak InSight, Kodak Ektaspeed Plus, Kodak Ultra-speed and Kodak D-speed films were evaluated. All films were exposed together with aluminium wedge, at times ranging from 0,1-1 second. By plotting a graphic of density against exposure, sensitometric properties were compared. Agfa Dentus M2 “Comfort" and Kodak InSight films obtained the highest film speed; Kodak Ultra-speed and Kodak D-speed films exhibited the lowest sensitivity. Agfa Dentus M2 “Comfort" and Kodak InSight films had presented valuesm to contrast superior to other films. Therefore, Agfa Dentus M2 “Comfort" and Kodak InSight films must be recommended to minimize the radiation dose to the patient.