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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

Performance of near infared digital imaging transillumination for detection of non-cavitated approximal caries

Abogazalah, Naif Nabel Fouad 01 June 2016 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Objective: The objectives of this in-vitro study were: 1) to evaluate the ability of Near-Infrared Digital Imaging Transillumination (NIDIT) to detect non-cavitated approximal caries lesions; and 2) to compare the performance among NIDIT, Digital Radiography (DR), Digital Imaging Fiber-Optic Trans-Illumination (DIFOTI) and International Caries Detection and Assessment System (ICDAS). Methods: Thirty human extracted premolars were selected. The approximal surface status ranged from sound to surfaces with non-cavitated caries lesions into the outer one-third of the dentin. Lesion depth was determined by micro-computed tomography (μ-CT) and used as a gold standard. Teeth were mounted in a custom-made device to simulate approximal contact. ICDAS, DR, DIFOTI and NIDIT examinations were performed and repeated by three trained and calibrated examiners. Sensitivity, specificity, area under ROC curve (Az), inter- and intra-class correlation coefficients (ICCs) of each method, and correlation among the methods were determined. Results: ICCs for intra-/inter-examiner agreement were almost perfect for DIFOTI (0.85/0.83), substantial for ICDAS (0.79/0.72) and NIDIT (0.69/0.64), and moderate for DR (0.52/0.48). Sensitivity/specificity for DIFOTI, ICDAS, DR, and NIDIT were 0.91/0.69, 0.89/0.83, 0.50/0.64, and 0.68/0.93, respectively. Az of DR (0.61) was significantly lower than that of DIFOTI (0.91, p = 0.002) and ICDAS (0.90, p = 0.005), but was not significantly different from NIDIT (0.81, p = 0.052). DIFOTI, ICDAS, and NIDIT were not significantly different from each other (p > 0.13). Spearman correlation coefficients for DIFOTI (0.79, p < 0.001), ICDAS (0.74, p < 0.001), and NIDIT (0.65, p < 0.001) demonstrated a moderate association with μ-CT, while that of DR suggested no association (0.19, p = 0.289). Conclusion: Within the limitations of this in-vitro study, NIDIT system demonstrated a potential for early approximal caries detection. ICDAS, DIFOTI, and NIDIT were superior to DR in terms of validity and reliability.
472

Neutron Radiographic Imaging Analysis

Butler, Michael Paul January 1980 (has links)
<p> In analyzing the processes involved in neutron radiography, there is a need for a well-defined mathematical structure which can simultaneously be used in practical situations without great difficulty. In this report, the edge-spread function method of analysis is considered in some detail. The basic theory is developed, and both the general and the specific viewpoint are considered, in terms of the mathematical functions used. The usefulness of ESF theory in predicting optical density patterns is illustrated. Specific applications of the theory are developed; in particular, studies of image resolution and unsharpness are undertaken. </p> <p> To determine whether or not ESF methods are a good representation of the physical situation, some alternate methods which consider radiography from a more basic viewpoint are developed. The first of these is a strictly numerical approach, where experimental data is examined without specifying a model for the image formation process; a matrix formulation suitable for characterizing an image is developed. </p> <p> The second alternate method involves the use of Monte Carlo methods; this allows the incorporation of more realistic parameters into the analysis. For example, screen-film separation and object scattering of neutrons, and their effects on the image, are evaluated. Finally, a two-dimensional analysis of a simple problem is considered, with the end result being a confirmation of the usefulness of ESF theory. </p> / Thesis / Master of Engineering (MEngr)
473

Radiographic imaging of neonates with digital and analog techniques : Comparative evaluation of dose and image quality / Ακτινογραφική απεικόνιση νεογνών με ψηφιακές και αναλογικές τεχνικές : Συγκριτική αξιολόγηση δόσης και ποιότητας εικόνας

Τακτικού, Ελευθερία 26 July 2013 (has links)
Diagnostic radiology plays an important role in the assessment and treatment of neonates, mainly premature, requiring intensive care in the Special Baby Care Unit (SBCU), because they have highly mitotic state of their cells and thus they are more radiosensitive. It is often necessary to perform a large number of X-ray examinations depending upon the infant's birth-weight, gestational age and respiratory problems. It is therefore important to ensure that radiation doses from radiographic examinations carried out in neo-natal units are kept to a minimum while maintaining the quality of radiographic images in a high level. An optimization study on radiation dose and image quality in neonatal radiography is presented. Our sample consists of 135 neonatal radiographic examinations, which performed on 54 neonates. All examinations were performed using the same mobile unit and under manual exposure control. Neonates were categorized into four groups depending on birth-weight. ESD was estimated from the exposure parameters (kVp, mAs) and tube output and also with using of Dose-Area Product (DAP). For the evaluation of image quality, our sample consists of 195 images (75 screen film images, 60 CR images in printed form and 60 CR images in electronic form) were assessed by two observers and were based on the visibility of certain anatomical features using a five-grade scale. ESDoutput values increased with increasing weight and ranged from 16.8 μGy to 64.7 μGy, with a mean value of 36 μGy for all radiographs. Similarly, ESDDAP values ranged from 14.8 μGy to 48.5 μGy with a mean of 29 μGy. Analyzing, the mean ESD for CR images was found 34.8 μGy and for screen film images 36.9 μGy. ESD values for CR images have the same behavior as ESD values for SF images. However, the majority of the acquired values are lower than the proposed Dose Reference Levels by Commission of European Communities (CEC: 80 μGy) and National Radiological Protection Board (NRPB: 50 μGy). Image quality evaluation revealed the feasibility of achieving a diagnostically satisfactory image using both low and high tube voltage techniques, with the latter resulting in reduced ESDs. The results suggest that the use of high tube voltage techniques could result in further reductions in neonatal dose, without image quality degradation, underlying the requirement for establishing standard examination protocols for neonatal radiography with respect to neonatal weight. / Η Διαγνωστική ακτινολογία παίζει σημαντικό ρόλο στην αξιολόγηση και τη θεραπεία των νεογνών, κυρίως των πρόωρων, καθώς απαιτείται η εντατική φροντίδα τους στην Ειδική Μονάδα Φροντίδας Νεογνών, λόγω της μεγάλης μιτωτικής δραστηριότητας των κυττάρων τους και κατα συνέπεια της ακτινοευαισθησίας τους. Είναι συχνά απαραίτητο να πραγματοποιηθεί ένας μεγάλος αριθμός ακτινογραφικών εξετάσεων που εξαρτώνται από το βάρος γέννησης, την περίοδο κύησης και τα αναπνευστικά προβλήματα. Επομένως, είναι σημαντικό να εξασφαλιστεί ότι οι δόσεις ακτινοβολίας από ακτινογραφικές εξετάσεις που πραγματοποιούνται σε μονάδες νεογνών περιορίζονται στο ελάχιστο, ενώ η ποιότητα των ακτινογραφικών εικόνων διατηρείται σε υψηλά επίπεδα. Μια μελέτη για τη βελτιστοποίηση της δόσης της ακτινοβολίας και της ποιότητας της εικόνας σε ακτινογραφίες νεογνών παρουσιάζεται παρακάτω. Το δείγμα μας αποτελείται από 135 ακτινογραφικές εξετάσεις νεογνών, οι οποίες πραγματοποιήθηκαν σε 54 νεογνά. Όλες οι εξετάσεις πραγματοποιήθηκαν χρησιμοποιώντας την ίδια φορητή ακτινογραφική μονάδα και με χειροκίνητο έλεγχο έκθεσης. Τα νεογνά ταξινομήθηκαν σε τέσσερις ομάδες ανάλογα με το βάρος γέννησης. Η Επιφανειακή δόση (ESD) εκτιμήθηκε από τις παραμέτρους της έκθεσης (kVp, mΑs), αλλά και με τη χρήση του DAP. Για την αξιολόγηση της ποιότητας της εικόνας, το δείγμα αποτελούνταν από 195 εικόνες (75 συμβατικές, 60 ψηφιακές (CR) σε έντυπη μορφή και 60 ψηφιακές εικόνες (CR) σε ηλεκτρονική μορφή) οι οποίες αξιολογήθηκαν από δύο παρατηρητές και βασίστηκαν στην ορατότητα ορισμένων ανατομικών χαρακτηριστικών χρησιμοποιώντας μια πενταβάθμια κλίμακα. Οι ESDoutput τιμές αυξάνονται με την αύξηση του βάρους και κυμαίνονται από 16.8μGy σε 64.7μGy, με μέση τιμή 36μGy για όλες τις ακτινογραφίες. Ομοίως, οι ESDDAP τιμές κυμαίνονται από 14.8 μGy σε 48.5 μGy, με μέση τιμή 29 μGy. Αναλυτικά, η μέση τιμή ESD για τις ψηφιακές (CR) εικόνες βρέθηκε 34.8μGy και για τις συμβατικές 36.9μGy. Η ESD για CR εικόνες έχει στατιστικά την ίδια συμπεριφορά με την ESD για SF εικόνες. Η πλειοψηφία των αποκτηθέντων τιμών είναι χαμηλότερες από τα Διαγνωστικά Επίπεδα Αναφοράς που έχουν προταθεί από την Επιτροπή της Ευρωπαϊκής Ένωσης (CEC: 80μGy) και το National Radiological Protection Board (NRPB: 50μGy) για προσθοπίσθιες ακτινογραφίες θώρακος νεογνών. Η αξιολόγηση της ποιότητας της εικόνας αποκάλυψε την δυνατότητα επίτευξης μιας διαγνωστικά ικανοποιητικής εικόνας χρησιμοποιώντας τόσο χαμηλές όσο και υψηλές τάσεις, με τις τελευταίες να οδηγούν σε μείωση των επιφανειακών δόσεων (ESDs). Τα αποτελέσματα δείχνουν ότι η χρήση τεχνικών υψηλής τάσης μπορούν να οδηγήσουν σε περαιτέρω μείωση των δόσεων στα νεογνά, χωρίς να υποβαθμίζεται η ποιότητα της εικόνας, τα οποία βασίζονται στην απαίτηση καθορισμού τυποποιημένων πρωτοκόλλων εξέτασης για ακτινογραφίες σε νεογνά σε σχέση με το βάρος τους.
474

Alveolar bone loss in radiographic modalities for diagnosis of periodontal disease / Periodonto ligų diagnozavimas: dantinės ataugos pokyčių analizė, taikant skirtingus rentgeninio tyrimo metodus

Ivanauskaitė, Deimantė 21 June 2011 (has links)
Radiographic modalities are used in addition to clinical methods to gain information about the patients. In the examination of the periodontium, which is comprised of the gingiva, alveolar bone, periodontal ligament, and cementum, the radiographic examination plays an integral role for diagnosis of periodontal disease. The diagnosis periodontitis is based on a finding of alveolar bone loss. Changes of the alveolar bone can be assessed by different radiographic modalities, such as intraoral radiography (bitewing and periapical radiography) and panoramic radiography. Analysis of alveolar bone loss (alveolar bone level, detection of vertical bone defect and furcation involvement) in radiographic modalities and a systematic review could be helpful to suggest the more applicable radiographic methods for diagnosis of periodontal disease. The purpose of the present study was to examine diagnostic properties of panoramic radiography for the assessment of alveolar bone loss for the diagnosis of periodontal diseases as compare to posterior bitewing radiography. For 96 patients panoramic and posterior bitewing radiographs were performed and results of analysis of visibility of radiographic images and assessment of alveolar bone loss were compared. Also, the systematic review on diagnostic properties of panoramic radiography in the assessment of alveolar bone loss was performed. Based on the results of this study, recommendations for clinical practice and for research were proposed. / Rentgeniniai tyrimo metodai taikomi, kad būtų papildyti klinikinio tyrimo duomenys. Tiriant periodontą, kurį sudaro dantenos, dantinė atauga, periodonto raiščiai ir cementas, rentgeninis tyrimas svarbus diagnozuojant periodonto ligas, nes jo metu nustatomi dantinės ataugos pokyčiai. Dantinės ataugos pokyčiams vertinti daromos rentgeno nuotraukos taikant vidinių burnos rentgeno nuotraukų darymo metodus, t. y. kandimo ar dantų šaknų rentgeno nuotraukų darymo metodus, ir išorinės burnos rentgeno nuotraukos darymo metodą, t. y. panoraminės rentgeno nuotraukos darymo metodą. Atlikus dantinės ataugos pokyčių (kaulo lygio arba rezorbcijos, kaulo defekto ir tarpšaknio kaulo pažeidimų) analizę, taikant rentgeninius metodus, ir padarius sisteminę literatūros apžvalgą, galima būtų pasiūlyti tinkamiausią rentgeno metodą periodonto ligoms diagnozuoti. Šio darbo tikslas – ištirti ir palyginti panoraminės rentgeno nuotraukos ir kaplių bei krūminių dantų rentgeno nuotraukų darymo metodų diagnostikos ypatybes vertinant dantinės ataugos pokyčius periodonto ligoms diagnozuoti. Kiekvienam, iš 96 pacientų įtrauktų į tyrimą, buvo padaryta panoraminė rentgeno nuotrauka ir kaplių bei krūminių dantų kandimo rentgeno nuotraukos. Atlikta dantinės ataugos rentgeno atvaizdo vizualioji kokybė analizė ir vertinimai skirtingose rentgeno nuotraukose bei palyginti rezultatai. Padaryta sisteminė literatūros apžvalga apie panoraminės rentgeno nuotraukos vertę diagnozuojant periodonto ligas. Pagal šio tyrimo... [toliau žr. visą tekstą]
475

Periodonto ligų diagnozavimas: dantinės ataugos pokyčių analizė, taikant skirtingus rentgeninio tyrimo metodus / Alveolar bone loss in radiographic modalities for diagnosis of periodontal diseases

Ivanauskaitė, Deimantė 21 June 2011 (has links)
Rentgeniniai tyrimo metodai taikomi, kad būtų papildyti klinikinio tyrimo duomenys. Tiriant periodontą, kurį sudaro dantenos, dantinė atauga, periodonto raiščiai ir cementas, rentgeninis tyrimas svarbus diagnozuojant periodonto ligas, nes jo metu nustatomi dantinės ataugos pokyčiai. Dantinės ataugos pokyčiams vertinti daromos rentgeno nuotraukos taikant vidinių burnos rentgeno nuotraukų darymo metodus, t. y. kandimo ar dantų šaknų rentgeno nuotraukų darymo metodus, ir išorinės burnos rentgeno nuotraukos darymo metodą, t. y. panoraminės rentgeno nuotraukos darymo metodą. Atlikus dantinės ataugos pokyčių (kaulo lygio arba rezorbcijos, kaulo defekto ir tarpšaknio kaulo pažeidimų) analizę, taikant rentgeninius metodus, ir padarius sisteminę literatūros apžvalgą, galima būtų pasiūlyti tinkamiausią rentgeno metodą periodonto ligoms diagnozuoti. Šio darbo tikslas – ištirti ir palyginti panoraminės rentgeno nuotraukos ir kaplių bei krūminių dantų rentgeno nuotraukų darymo metodų diagnostikos ypatybes vertinant dantinės ataugos pokyčius periodonto ligoms diagnozuoti. Kiekvienam, iš 96 pacientų įtrauktų į tyrimą, buvo padaryta panoraminė rentgeno nuotrauka ir kaplių bei krūminių dantų kandimo rentgeno nuotraukos. Atlikta dantinės ataugos rentgeno atvaizdo vizualioji kokybė analizė ir vertinimai skirtingose rentgeno nuotraukose bei palyginti rezultatai. Padaryta sisteminė literatūros apžvalga apie panoraminės rentgeno nuotraukos vertę diagnozuojant periodonto ligas. Pagal šio tyrimo... [toliau žr. visą tekstą] / Radiographic modalities are used in addition to clinical methods to gain information about the patients. In the examination of the periodontium, which is comprised of the gingiva, alveolar bone, periodontal ligament, and cementum, the radiographic examination plays an integral role for diagnosis of periodontal disease. The diagnosis periodontitis is based on a finding of alveolar bone loss. Changes of the alveolar bone can be assessed by different radiographic modalities, such as intraoral radiography (bitewing and periapical radiography) and panoramic radiography. Analysis of alveolar bone loss (alveolar bone level, detection of vertical bone defect and furcation involvement) in radiographic modalities and a systematic review could be helpful to suggest the more applicable radiographic methods for diagnosis of periodontal disease. The purpose of the present study was to examine diagnostic properties of panoramic radiography for the assessment of alveolar bone loss for the diagnosis of periodontal diseases as compare to posterior bitewing radiography. For 96 patients panoramic and posterior bitewing radiographs were performed and results of analysis of visibility of radiographic images and assessment of alveolar bone loss were compared. Also, the systematic review on diagnostic properties of panoramic radiography in the assessment of alveolar bone loss was performed. Based on the results of this study, recommendations for clinical practice and for research were proposed.
476

Approche multi-énergies associée à un détecteur spectrométrique rayons X pour l’identification de matériaux / Multi-energy methods for material identification using an X-ray spectrometric photon counting detector

Beldjoudi, Guillaume Nordine 19 September 2011 (has links)
Le développement des détecteurs de rayons X en comptage à base de semiconducteurs est en plein essor depuis une dizaine d’années, et des applications aussi bien dans le domaine médical que dans le domaine du contrôle non destructif sont envisagées. Ces détecteurs permettent en effet de réaliser des mesures à des énergies multiples en une seule acquisition, et ce avec une excellente séparation énergétique. Depuis les années 2008-2009, il semble qu’une véritable course se soit lancée pour le développement de détecteur permettant des mesures multi-énergies sur un nombre toujours plus nombreux de bandes d’énergies. Cependant, à ce jour, parmi l’ensemble des travaux qui ont été réalisés, l’intérêt de réaliser des mesures sur un grand nombre d’énergies n’a pas été démontré pour l’identification de matériaux. Dans le cadre d’une étude en sécurité, nous avons évalué l’intérêt lié à l’utilisation de détecteurs de rayons X en comptage permettant la réalisation de mesures sur plusieurs bandes d’énergies. Le domaine applicatif étudié concerne l’identification de matériaux dans les bagages des voyageurs. Nous avons tout d’abord développé une méthode originale d’identification de matériaux homogènes applicable à tout type de détecteur multi-énergies. Dans un premier temps, nous avons étudié, en simulation, l’évolution des performances d’identification de matériaux avec l’augmentation du nombre de bandes d’énergies de comptage. Un processus d’optimisation a été réalisé dans le but de déterminer, pour certaines configurations, une géométrie optimale des bandes d’énergies de comptage. Dans un second temps, les conséquences résultant de la prise en compte de la fonction de réponse du détecteur ont été quantifiées par la simulation de différents effets détecteurs (partage de charge, résolution en énergie). Une validation expérimentale a enfin pu être effectuée en utilisant un détecteur spectrométrique en comptage. À partir des mesures réalisées avec un tel détecteur, un regroupement des données nous a permis d’évaluer les performances d’identification de détecteurs possédant un nombre de bandes d’énergies de comptage différent. Enfin, nous avons mené une étude préliminaire sur la transposition à la tomographie multi-énergies de la méthode d’identification de matériaux homogènes développée initialement en radiographie. Cette modalité d’imagerie permet alors l’identification de matériaux superposés. / The development of X-ray photon counting detectors based on semiconductors has grown up over the last ten years, and applications in medicine, in security and in nondestructive testing are under study. These detectors make it possible to perform measurements at multiple energies in a single acquisition, with an excellent energetic separation. Since the years 2008-2009, it seems that a real race started for the development of detectors performing multi-energetic measurements on an increasing number of energy bands. However, today, within the works already done, the interest of performing measurements on a large number of energies has not been demonstrated for material identification. As part of a study in homeland security, we assessed the interest of using Xray counting detectors that perform measurements on multiple energy bands. The considered field of interest is material identification in the luggage of travelers. We first developed an original method for identifying single materials. This method is applicable to any type of multi-energy detector. In a first time, we studied in simulation the evolution of the performance for identifying materials with the increasing number of energy bands. An optimization process was carried out to determine, for certain configurations, an optimal geometry of the energy bands.In a second step, the consequences of taking into account the detector response function were quantified by simulating different sensors effects (charge sharing, energy resolution). An experimental validation has been performed by using a counting spectrometric detector. From the measurements experimentally obtained with such a detector, combining the data allowed us to evaluate the identification performance that would have detectors possessing a different number of energy bands. Finally, we conducted a preliminary study on the transposition of the identification method initially developed for radiography to the multi-energy computed tomography. This imaging modality allows to identify superimposed materials.
477

"Avaliação da densidade óptica da sutura palatina mediana por meio do sistema de radiografia digital por placa fotoativada em pacientes submetidos a disjunção palatina" / "Evaluation of the optic density on the medium suture palatiny by means of digital x-ray system for plate fotoativada in patients submitted ti palatine disjunction"

Melo, Maria de Fatima Batista de 12 June 2003 (has links)
RESUMO A Expansão Rápida da Maxila é um recurso clínico adotado pelos ortodontistas no tratamento das más oclusões com deficiência transversa real ou relativa da maxila. Esta, inclui uma fase ativa, promovendo a desarticulação dos ossos maxilares por meio da sutura, e uma fase passiva, onde uma série de eventos levam à remodelação óssea e restauração da sutura, com o aumento clínico na largura do palato. Discute-se qual a melhor época para a disjunção e o tempo necessário para que haja a perfeita remodelação óssea. A radiografia oclusal assume aqui um importante papel, pois é por meio desta que se obtém a imagem da sutura palatina mediana permitindo uma análise descritiva de suas condições em todas as etapas do tratamento A nossa proposta no presente estudo, foi a de medir as densidades ópticas da sutura palatina mediana antes da disjunção (Fase I), imediatamente após a disjunção, (Fase II) e após contenção de três meses (Fase III), usando um sistema de imagem digital, comparando-as e correlacionando-as com a radiografia oclusal convencional. A amostra, constituída por 31 (trinta e um) pacientes que se submeteriam à disjunção palatina e que se encontravam em fase de crescimento, foi dividida em:grupo I, constituído pelos pacientes de dentadura mista e grupo II, pelos pacientes de dentadura permanente. Foram obtidas radiografias oclusais e imagens digitais nas fases Fase I, Fase II e na Fase III. Áreas de interesse foram demarcadas nas radiografias digitais, procedendo-se a leitura das densidades ópticas pelo programa Digora for Windows-2.1, e comparando os resultados entre si e com a avaliação subjetiva feita nas radiografias oclusais. Após a análise dos dados pelo teste t de Student pareado, pode-se concluir que 1) as densidades ópticas da sutura palatina mediana na fase final, mostram valores inferiores aos da fase inicial nos pacientes do grupo I; 2) as densidades ópticas da sutura palatina mediana na fase final, mostram valores semelhantes aos da fase inicial nos pacientes do grupo II; 3) as densidades ópticas finais da sutura palatina mediana não correspondem às iniciais nos pacientes do sexo feminino do grupo I; 4) as densidades ópticas finais da sutura palatina mediana são semelhantes às iniciais nos pacientes do sexo masculino do grupo II; 5) para os pacientes do grupo II não houve diferença significante entre os valores de densidade óptica inicial e final, tanto no sexo masculino como feminino; 6) os resultados encontrados nas imagens digitais são compatíveis com os encontrados nas radiografias oclusais convencionais. / SUMMARY The Fast Expansion of the Jaw is a clinical resource adopted by the ortodontists in the treatment of the bad occlusions with real or relative deficiency transversal, of the jaw. This, includes a phase, promoting the disarticulation of the maxilarys bones by means of the suture, and a passive phase, where a series of events takes to the bone remodelling and restoration of the suture, with the clinical increase in the width of the palate. The best time for the disjunction and the necessary time is argued which so that it has the perfect bone remodelling. The oclusal radiography assumes an important role here, therefore it is for way of this that if gets the image of the medium palatine suture allowing to a descriptive analysis of its conditions in all the stages of the treatment our proposal in the present study, was to measure the optic densities of the medium palatine suture before the disjunction (Phase I), immediately after the disjunction, (Phase II) and after containment three months (Phase III), using a system of digital image, comparing and correlating them with the conventional oclusal radiography. The sample, consisting of 31 (thirty one) patient that would submitted the palatine disjunction and that found in growth phase, divided in Grave I, constituted of the patients of mixing set of teeth and group II, for the permanent set of teeth patients. Oclusal radiography and digital images in the phases had been gotten Phase I, Phase II and in Phase III. Areas of interest had been demarcated in the digital x-rays, proceeding it reading from the optic densities for the Digora program for Windows-2.1, and comparing the results among themselves. With the subjective evaluation in the oclusal radiographies.(After the analysis of the data by student T test could be concluded that1) the opitic densities of the medium palatine suture in the final phase, show inferior values to the ones of the initial phase in the patients of group I;2) the optic densities of the medium palatine suture in the final phase, show similar values to the ones of the initial phase in the patients of group II;3) the final optic densities of the medium palatine suture do not correspond to the initials in the patients of the female groupI;4) the final opitic densities of the medium palatine suture are similar to the initials in the patients of the male group II;5) for the patients of group II it did not have significant difference betweenthe values of initial and final opitic density, as much in the male and female groups6) the results found in the digital images are compatible wit those found in the conventional oclusal radiographics.
478

Computational techniques for statistical morphometric analysis of 3-D MRI data of human skull and brain. / 統計形態分析之計算方法及其核磁共振影像應用 / Computational techniques for statistical morphometric analysis of three-dimensional MRI data of human skull and brain / CUHK electronic theses & dissertations collection / Tong ji xing tai fen xi zhi ji suan fang fa ji qi he ci gong zhen ying xiang ying yong

January 2008 (has links)
Shi, Lin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 171-185). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.
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Pneumatização do tubérculo articular do osso temporal / Temporal bone pneumatized articular tubercule

Abreu, Marcos Petto Nunes de 07 November 2007 (has links)
A pneumatização do tubérculo articular do osso temporal (PTA) é uma variação anatômica, observada radiograficamente como uma área radiolúcida uni ou multilocular, similar às observadas nas células aéreas do processo mastóide do osso temporal, não expansiva ou destrutiva, e não se estendendo além da sutura zigomático-temporal. No presente trabalho nos propusemos a conhecer, por meio do levantamento epidemiológico de 3823 radiografias panorâmicas, a incidência e as características da PTA em pacientes atendidos pelo Serviço de Radiologia da Clínica de Odontologia da Faculdade de Odontologia da Universidade de São Paulo. A PTA foi encontrada em 68 pacientes (1,78%) com idade cronológica média de 40 anos (±20,85) em intervalo etário de 8 a 87 anos; sendo que destes casos, 39 (57,4%) ocorreram no gênero feminino e 29 (42,6%) no gênero masculino. A PTA ocorreu unilateralmente em 42 casos (61,8%) e bilateralmente em 26 casos (38,2%). Radiograficamente 42 (44,6%) eram de padrão unilocular e 52 (55,4%) de padrão multilocular. O reconhecimento da PTA é de suma importância para se evitar interpretações incorretas com afecções e avaliar sua influência na evolução de processos sépticos, na reparação tecidual e no planejamento cirúrgico na região da articulação têmporo-mandibular. / The temporal bone pneumatized articular tubercule (PAT) is a anatomical variant, seen on radiographs as a unilocular or multilocular radiolucency, similar to those in mastoid process, noexpansile or nondestructive, and do not extend beyond the zygomatictemporal suture. The purpose of this study was to know, by a epidemilogical analysis of 3823 panoramic radiographs, the incidence and characteristics of the PAT, in dental patients from the Dental Clinic, at the Radiology service in University of São Paulo. The PAT was found in 68 patients (1,78%) with mean cronological age of 40 years (± 20,85) with a range of 8 to 87 years; while 39 (57,4%) occured in females and 29 (42,6%) in male. Unilateral PAT was found in 42 cases (44,6%) and bilateral in 26 cases (38,2%). Radiography aspects showed 42 cases (44,6%) as unilocular and 52 cases (55,4%) as multilocular. The knowledge of the PAT is very important to avoid misdiagnosis within other diases ocorring in the area, and avaliate her influency in the evolution of septic process, realing process, and at the cirurgical management of the temporomandibular joint.
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Avaliação de defeitos ósseos alveolares artificiais utilizando radiografia digital direta e tomografia computadorizada por feixe cônico / Assessment of artificially created alveolar bone defects using direct digital radiography and cone beam computed tomography

Campos Junior, Adinilton Ferraz de 31 October 2008 (has links)
Introdução A abordagem do estudo dos recursos imaginológicos aplicados à análise óssea diz respeito ao estudo topográfico do periodonto e suas alterações. Consiste em avaliar a contribuição dos referidos recursos em razão das limitações dos exames convencionais. Objetivo Analisar por meio de dois sistemas de imagens digitais: a radiografia digital direta e a tomografia computadorizada por feixe cônico, comparando a eficácia de cada aparelho na análise das corticais do tecido periodontal e suas alterações. Métodos Cinco espécimes de mandíbulas foram incluídos em nosso estudo, com 6 tipos de defeitos ósseos distribuídos no septo interdentário e na porção radicular do dente. Radiografias periapicais foram realizadas, com o sensor sensor Dixi®2 (Planmeca Oy, Helsinki, Finlândia), e exames tomográficos, com o aparelho Newtom 3G (QR Srl, Verona, Itália). A pesquisa qualitativa, de caráter subjetivo, contemplou a análise das corticais ósseas avaliadas por três observadores em um total de 40 sítios para cada modalidade de exame. Teste estatístico de McNemar foi empregado para análise inter e intraobservadores. Resultados Resultados não concordantes foram relacionados à sobreposição de estruturas anatômicas em sua maior parte pela radiografia digital direta. Os resultados de acerto da tomografia computadorizada por feixe cônico: para análise da cortical vestibular do septo interdentário foi de 84%; para a cortical lingual de 92%; para a cortical proximal de 80%; e para cortical radicular de 80%, contra 60%, 64%, 80% e 46% respectivamente da radiografia digital. Não foram encontradas diferenças entre a 1ª e a 2ª análises na avaliação intra-observadores, contudo houve variação inter-observadores. Conclusões A tomografia computadorizada por feixe cônico mostrou-se como potencial recurso de imagem para análise das corticais ósseas do tecido periodontal. Entretanto, os resultados também apontaram que ambos os métodos são observador-dependentes, havendo necessidade de profissionais habilitados para utilização desses recursos recentes de imagem. Também avaliamos que estudos adicionais deveriam ser aplicados para maior entendimento do assunto estudado. / Introduction The study of the imaging resources applied to bone analysis regards to the topographic study of the periodontium and its changes. It is an assessment of the contribution of the related resources as compared to the limitations of conventional exams. Objective To analyze two digital imaging systems: the direct digital radiography and the cone beam computed tomography, comparing the efficacy of each device to analyze the cortical plates of the periodontal tissue and its changes. Methods Five mandible specimens were included in our study, with 6 types of bone defects distributed on the interdental septum and on the radicular portion of the tooth. Periapical radiographs with the Dixi®2 sensor (Planmeca Oy, Helsinki, Finland) and tomographic scans with Newtom 3G device (QR Srl, Verona, Italy) were obtained. The qualitative research, with a subjective feature, included the analysis of the bone cortical plates for a total of 40 sites with each examination method carried out by three observers. The McNemar statistic test was used for inter and intraobserver analyses. Results Results which did not agree were related to the overlay of anatomic structures mainly due to the direct digital radiography. The correct results for cone beam computed tomography were: 84% for the analysis of vestibular cortical plate of the interdental septum; 92% for lingual cortical plate; 80% for proximal cortical plate; and 80% for radicular cortical plate, against 60%, 64%, 80% e 46%, respectively, with digital radiography. No differences were found between the 1st and 2nd intraobserver analyses, but there was interobserver variation. Conclusion The cone beam computed tomography was shown to be a potential imaging resource for the analysis of the bone cortical plates of the periodontal tissue. However, the results also showed that both methods are observer-dependent, and there is a need for skilled professionals to use this recent imaging technology. In addition, we considered the additional studies that should be applied to improve the understanding of this subject.

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