Dissertations / Theses: 'Digital radiographic'

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Davidson, Robert Andrew. "Radiographic contrast-enhancement masks in digital radiography." University of Sydney, 2006. http://hdl.handle.net/2123/1932.

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Doctor of Philosophy Radiographic film/screen (F/S) images have a narrow latitude or dynamic range. The film’s ability to record and view all the anatomy within the x-ray field is limited by this narrow dynamic range. The advent of digital radiographic means of storing and displaying radiographic images has improved the ability to record and visualise all of the anatomy. The problem still exists in digital radiography (DR) when radiographic examinations of certain anatomical regions are undertaken. In this work, the value of anatomically shaped radiographic contrast-enhancement masks (RCMs) in improving image contrast and reducing the dynamic range of images in DR was examined. Radiographic contrast-enhancement masks are digital masks that alter the radiographic contrast in DR images. The shape of these masks can be altered by the user. Anatomically shaped RCMs have been modelled on tissue compensation filters (TCFs) commonly used in F/S radiographic examinations. The prime purpose of a TCF is to reduce the dynamic range of photons reaching the image receptor and hence improve radiographic contrast in the resultant image. RCMs affect the dynamic range of the image rather than the energy source of the image, that of the x-ray photons. The research consisted of three distinct phases. The first phase was to examine physical TCFs and their effects on F/S radiographic images. Physical TCFs are used in radiographic F/S examinations to attenuate the x-ray beam to compensate for varying patient tissue thicknesses and/or densities. The effect of the TCF is to reduce resultant radiographic optical density variations in the image, allowing the viewer to observe a range of densities within the image which would otherwise not be visualised. Physical TCFs are commonly aluminium- or lead-based materials that attenuate the x-ray beam. A TCF has varying physical thickness to differentially attenuate the iii beam and is shaped for specific anatomical situations. During this project, various commonly used physical TCFs were examined. Measurements of size and thickness were made. Characteristics of linear attenuation coefficients and half-value thicknesses were delineated for various TCF materials and at various energies. The second phase of the research was to model the physical TCFs in a digital environment and apply the RCMs to DR images. The digital RCMs were created with similar characteristics to mimic the shapes to the physical TCFs. The RCM characteristics can be adjusted by the viewer of the image to suit the anatomy being imaged. Anatomically shaped RCMs were designed to assist in overcoming a limitation when viewing digital radiographic images, that of the dynamic range of the image. Anatomically shaped RCMs differ from other means of controlling the dynamic range of a digital radiographic image. It has been shown that RCMs can reduce the range of optical densities within images with a large dynamic range, to facilitate visualisation of all anatomy within the image. Physical TCFs are used within a specific range of radiographic F/S examinations. Digital radiographic images from this range of examinations were collected from various clinical radiological centres. Anatomically shaped RCMs were applied to the images to improve radiographic contrast of the images. The third phase of the research was to ascertain the benefits of the use of RCMs. Various other methods are currently in use to reduce the dynamic range of digital radiographic images. It is generally accepted that these methods also introduce noise into the image and hence reduce image quality. Quantitative comparisons of noise within the image were undertaken. The anatomically shaped RCMs introduced less noise than current methods designed to reduce the dynamic range of digital radiographic images. It was shown that RCM methods do not affect image quality. Radiographers make subjective assessment of digital radiographic image quality as part of their professional practice. To assess the subjective quality of images enhanced with anatomically shaped RCMs, a survey of radiographers and other iv qualified people was undertaken to ascertain any improvement in RCM-modified images compared to the original images. Participants were provided with eight pairs of image to compare. Questions were asked in the survey as to which image had the better range of optical densities; in which image the anatomy was easiest to visualise; which image had the simplest contrast and density manipulation for optimal visualisation; and which image had the overall highest image quality. Responses from 123 participants were received and analysed. The statistical analysis showed a higher preference by radiographers for the digital radiographic images in which the RCMs had been applied. Comparisons were made between anatomical regions and between patient-related factors of size, age and whether pathology was present in the image or not. The conclusion was drawn that digital RCMs correctly applied to digital radiographic images decrease the dynamic range of the image, allowing the entire anatomy to be visualised in one image. Radiographic contrast in the image can be maximised whilst maintaining image quality. Using RCMs in some digital radiographic examinations, radiographers will be able to present optimised images to referring clinicians. It is envisaged that correctly applied RCMs in certain radiographic examinations will enhance radiographic image quality and possibly lead to improved diagnosis from these images.

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Irvine, Michael Alan, and thebovus@yahoo com. "Image Quality and Radiation Dose Comparison of a Computed Radiography System and an Amorphous Silicon Flat Panel System in Paediatric Radiography: A Phantom Study." RMIT University. Applied Sciences, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091019.122013.

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This purpose of this work was to investigate the patient radiation doses and image quality of a Philips/Agfa computed radiographic (CR) system and a Philips indirect-capture digital radiographic (DR) system in a paediatric setting. A CDRAD digital radiographic contrast-detail phantom was used to assess radiographic image quality. Perspex slabs of three different thicknesses (6, 11 and 16 cm) were used to simulate paediatric patients of three arbitrary ages. These phantoms, in conjunction with the CDRAD digital radiographic contrast-detail phantom, were imaged under three different conditions. The CDRAD Analyser software package was used to assess the quality of each image. The first experiment conducted was a comparison of the two systems under standard conditions, with beam filtration of aluminium and copper, as recommended in European Guidelines on Quality Criteria for Diagnostic Radiographic Images in Paediatrics (European Commission 1996b). Image quality was compared for each phantom size at three doses with the same entrance exposure used for both systems. A visual comparison of the resulting contrast detail curves showed the DR system generally outperformed the CR system, especially at the lowest two doses. A chi-square analysis of the targets detected generally confirmed this visual impression. The second experiment performed was to compare the two systems under the conditions used in routine clinical practice at PMH. As a result of additional beam filtration not generally being employed, the image quality of the CR system was similar to the DR system for the two smaller phantom sizes but with a major dose cost - effective doses higher by between 38% and 100%. A chi-square analysis of the targets detected showed the CR system to be significantly better than the DR system at two of three doses for the thinnest phantom and no significant difference at any doses for the intermediate phantom size. For the largest phantom size, additional filtration - although different - was used for the CR and DR systems and so the X-ray beam spectra were more similar. Consequently, the results for this phantom size reflected those from the experiment conducted under standard conditions, ie the effective doses for both systems were similar and the image quality of the DR system superior. The chi-square analysis s howed the DR system to be significantly better than the CR at all three dose levels. A third experiment was undertaken to compare doses between the two systems at 'equal' image quality. The CDRAD Analyser software specific image quality parameter, IQFinv, was held constant for both systems. The entrance exposures required to achieve this image quality were measured and then converted to effective doses using the dose calculation software package PCXMC 1.5. The DR system offered effective dose savings of between 28 and 42% for the three phantom sizes. Overall, this work suggests that a Philips flat-panel system is superior to an Agfa CR system in paediatric radiography. This result generally reflects the findings of other authors who have conducted similar studies in adult patient settings.

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Pascoal, Ana Isabel Lourenco. "Optimisation of image quality and patient dose for chest radiography with digital radiographic systems." Thesis, King's College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438195.

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Bowen, Amber Jean. "Bone Density Measurement via Radiographic Calibration." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/341.

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Musculoskeletal injuries are the most common injuries sustained by athletes and military recruits and can result in decreased performance and lifelong disability. So common and costly are these injuries that the American Academy of Orthopedic Surgeons has provided guidelines for future research, including recommendations for the development of a large animal model of bone injury (USDA 2001). In human and veterinary medicine, digital radiography represents the primary diagnostic tool the physician uses to diagnose skeletal injury. Advances in digital radiography have provided the veterinarian with opportunities to make both simple and complex radiographic assessments. We investigated a simple quantitative measurement of the solar, concave aspect of the distal phalanx in the horse, termed the Palmar-Metric (PM). The PM was a significant predictor of solar cup volume (p < 0.001) and negatively correlated with age (r2 = 0.28, p < 0.05) as determined from 544 radiographs of the distal phalanx from the left and right front feet. Therefore, veterinarians should be aware of the age related change in the solar, concave aspect of the distal phalanx in the horse. We hypothesized that the decrease in the degree of concavity with age may be due to demineralization and subsequent loss of bone density along the solar margin of the distal phalanx. Therefore, we investigated the quantification of optical bone density (bone OD) via complex radiographic calibration. By developing a brightness/darkness index (BDI), the greyscale of radiographs, calibrated with an aluminum marker of varying known thickness, can be compared to the average density of a cross-section of bone. At varying radiographic exposure intensity (kV) and exposure time (mAs), Al BDI was a significant predictor of bone BDI (r2 = 0.960, p < 0.001) and bone OD (r2 = 0.971, p < 0.001). This method of calibration can be utilized by the radiologist to accurately assess bone OD regardless of technique, and allow direct comparison of radiographs taken under different exposure settings. This method successfully quantifies bone OD via measurement of BDI from standardized digital radiographs, allowing for the opacity of radiographs to be truly comparable when taken under different circumstances.

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Evanoff, Michael Geoffrey 1964. "Automatic identification of chest orientation in digital radiographic images." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282811.

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Radiology departments are implementing conversion from the use of hard copy film in favor of digital imaging. New digital acquisitions are increasing the efficacy of radiological imaging. The outputs of new modalities such as magnetic resonance (MR) and computed tomography (CT) are digital. They both involve gathering information that allows reconstructing cross sectional projections of internal structures and displaying them as digital images. Other technologies, e.g., computed radiography (CR), can provide digital radiographic data that replaces analog projection radiography. To date, the processed digital data is still transferred to film to provide a typical radiographic film in appearance. The film is presented to the doctor for diagnostic review. The research in this dissertation is concerned with making a film-less department. It specifically addresses problems in presenting CR images to the physician. The goal of this research is to create a computer recognition algorithm that will automatically recognize the orientation and discriminate between the lateral and posteroanterior view of digital chest radiographs image. The algorithm maintains 91.9% accuracy rate. The recognition takes .15 second per image.

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Offiah, Amaka. "Optimisation of the digital radiographic imaging of suspected non-accidental injury." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444875/.

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Aim: To optimise the digital (radiographic) imaging of children presenting with suspected non-accidental injury (NAI).;Objectives: (i) To evaluate existing radiographic quality criteria, and to develop a more suitable system if these are found to be inapplicable to skeletal surveys obtained in suspected NAI. (ii) To document differences in image quality between conventional film-screen and the recently installed Fuji5000R computed radiography (CR) system at Great Ormond Street Hospital for Children, (iii) To document the extent of variability in the standard of skeletal surveys obtained in the UK for suspected NAI. (iv) To determine those radiographic parameters which yield the highest diagnostic accuracy, while still maintaining acceptable radiation dose to the child, (v) To determine how varying degrees of edge-enhancement affect diagnostic accuracy. (vi) To establish the accuracy of soft compared to hard copy interpretation of images in suspected NAI.;Materials and Methods: (i) and (ii) Retrospective analysis of 286 paediatric lateral spine radiographs by two observers based on the Commission of European Communities (CEC) quality criteria, (iii) Review of the skeletal surveys of 50 consecutive infants referred from hospitals throughout the United Kingdom (UK) with suspected NAI. (iv) Phantom studies. Leeds TO. 10 and TO. 16 test objects were used to compare the relationship between film density, exposure parameters and visualisation of object details, (iv) Clinical study. Anteroposterior and lateral post mortem skull radiographs of six consecutive infants were obtained at various exposures. Six observers independently scored the images based on visualisation of five criteria, (v) and (vi) A study of diagnostic accuracy in which six observers independently interpreted 50 radiographs from printed copies (with varying degrees of edge-enhancement) and from a monitor.;Results: The CEC criteria are useful for optimisation of imaging parameters and allow the detection of differences in quality of film-screen and digital images. There is much variability in the quality and number of radiographs performed as part of skeletal surveys in the UK for suspected NAI. The Leeds test objects are either not sensitive enough (TO. 10) or perhaps over sensitive (TO. 16) for the purposes of this project. Furthermore, the minimum spatial resolution required for digital imaging in NAI has not been established. Therefore the objective interpretation of phantom studies is difficult. There is scope for reduction of radiation dose to children with no effect on image quality. Diagnostic accuracy (fracture detection) in suspected NAI is generally low, and is not affected by image display modality.;Conclusions: The CEC quality criteria are not applicable to the assessment of clinical image quality. A national protocol for skeletal surveys in NAI is required. Dedicated training, close supervision, collaboration and consistent exposure of radiologists to cases of NAI should improve diagnostic accuracy. The potential exists for dose reduction when performing skeletal surveys in children and infants with suspected NAI. Future studies should address this issue.

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Abdelkarim, Ahmad Ali. "Effect of JPEG2000 compression on landmark identification of lateral cephalometric digital radiographs a thesis /." San Antonio : UTHSC, 2008. http://learningobjects.library.uthscsa.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=57&CISOBOX=1&REC=16.

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Li, Gang. "Visual linearization of image data for the display of digital intraoral radiographs." Stockholm, 2004. http://diss.kib.ki.se/2003/91-85910-36-8.

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Moraes, Michelle Bianchi de. "Influência das variações de ângulos de projeção na detecção de reabsorções radiculares linguais e apicais simuladas: comparação entre subtração radiográfica digital e radiografia digital direta /." São José dos Campos: [s.n.], 2010. http://hdl.handle.net/11449/105861.

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Resumo: A reabsorção severa da raiz diagnosticada tardiamente pode acarretar a perda dentaria, e sendo a técnica de subtração radiográfica digital (SDR) um importante recurso para detecção precoce de alterações minerais, este estudo avaliou a eficiência no diagnóstico precoce da reabsorção radicular externa simulada apical e lingual, pela técnica de subtração radiográfica digital (SRD) e radiografia digital (RD). Foram utilizados 14 dentes incisivos de mandíbulas humanas maceradas com reabsorções de diferentes dimensões, simuladas na região apical e lingual, e radiografados com variação de ângulos de projeção. As radiografias foram subtraídas pelo programa Regeemy®, e para avaliação do desempenho dos métodos de diagnóstico, pares de radiografias periapicais e imagens subtraídas foram apresentadas a 2 radiologistas. De acordo com os resultados, não foram observadas diferenças estatisticamente significativas entre os métodos na detecção de reabsorções linguais, independentemente do tamanho da lesão, assim como não houve diferença entre os métodos na detecção de reabsorções apicais, com exceção do examinador 2 com relação a variação angular vertical e horizontal de 100 utilizando o maior nível de desgaste, que apresentou a radiografia digital como método superior na avaliação em relação a subtração radiográfica. E o aumento no nível de desgastes e a menor variação dos ângulos verticais e horizontais permitiram melhor avaliação nas regiões de reabsorções apicais e linguais, para detecção das reabsorções apicais e linguais. Com estes resultados podemos concluir que a subtração radiográfica digital é um exame indicado para detecção de pequenas perdas minerais em radiografias que apresentem pouca ou nenhuma variação nas angulações verticais e horizontais Abstract: The severe root resorption diagnosed late can lead to tooth loss, and being the technique of digital subtraction radiography (SDR) as an important resource for early detection mineral changes, this study evaluated the efficiency in the early diagnosis simulated external root resorption apical and lingual by the technique of digital subtraction radiography (SRD) and digital radiography (DR). We used 14 human incisors jaw macerated with resorption different sizes, simulated in the apical and lingual, and radiographed with a range of projection angles. The radiographs were subtracted by the program Regeemy ®, and performance evaluation diagnostic methods, pairs intraoral radiographs and subtracted images were presented to two radiologists. According to the results, there were no statistically significant differences between methods in the detection lingual resorption, regardless of lesion size, as there was no difference between the methods in the detection of apical resorption, except the second examiner with respect to variation vertical and horizontal angle of 100 using the highest level of wear, which lodged the digital radiography as a method superior in the evaluation for subtraction radiography. And the increase in the level of wear and less variation vertical and horizontal angles allowed a better assessment resorption in the regions apical and lingual to detect and lingual apical resorption. With these results we conclude that the digital subtraction radiography is a test for the detection of small mineral loss in radiographs showing little or no variation in vertical and horizontal angles Orientador: Mari Eli Leonelli de Moraes Coorientador: Jefferson Luis Oshiro Tanaka Banca: Rodrigo Dias Nascimento Banca: Edmundo Médicci Filho Banca: Milton Soares Gonçalves Banca: Warley David Kerbauy Doutor

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The, Bertram. "Digital radiographic preoperative planning and postoperative monitoring of total hip replacements techniques, validation and implementation /." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2006. http://irs.ub.rug.nl/ppn/297657615.

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Ley, Paul J. "An in-vitro comparison of working length determination between a digital system and conventional film when source-film/sensor distance and exposure time are modified." Connect to resource online, 2009. http://hdl.handle.net/1805/1928.

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Thesis (M.S.D.)--Indiana University School of Dentistry, 2009. Title from PDF t.p. (viewed Aug. 11, 2009) Advisors: Mychel Vail, Chair of the Research Committee, Susan Zunt, Ted Parks, Kenneth Sponik, Joseph Legan. Curriculum vitae. Includes abstract. Includes bibliographical references (leaves 103-119).

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Assis, Afonso Celso Souza de. "Estudo da viabilidade do emprego da técnica de subtração radiográfica digital em radiografias periapicais com registro a posteriori /." São José dos Campos : [s.n.], 2010. http://hdl.handle.net/11449/98003.

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Orientador: Luiz Cesar de Moraes Banca: Pedro Luiz de Carvalho Banca: Cristiane Yumi Koga Ito Resumo: Apesar de ser uma técnica limitada, a subtração digital é utilizada na Odontologia. A adição do computador e seus algoritmos para equalização de contraste e também correção geométrica, tornou possível a aplicação da subtração radiográfica digital (SRD), utilizando radiografias intrabucais. Neste estudo foi avaliada a viabilidade da utilização da subtração radiográfica digital pelo programa Regeemy - Image Registration and Mosaicking v.0.2.43-RCB (DPI-INPE, São José dos Campos, SP, Brazil) em radiografias periapicais digitalizadas e obtidas sem utilização de padronização rígida durante as exposições por meio de registro a posteriori. A seleção dos pontos de controle foram realizadas de forma automática e em quantidade múltipla pelo Reggemy. Esses pontos serviram como coordenadas a partir das quais o programa alinhou o par de imagens e gerou uma terceira imagem de acordo com a projeção geométrica da imagem de referência. Com o uso do Adobe Photoshop© foram selecionados os ROI das imagens utilizando guias e coordenadas. Depois de aplicados os testes estatísticos foi verificado que a metodologia do presente estudo não permite concluir que a subtração utilizando-se o programa Regeemy é inviável quando realizada sem padronização Abstract: The digital subtraction has been widely used in dentistry. The addition of computer and its algorithms for equalization of contrast and geometric correction also made possible the application of radiographic digital subtraction (SRD) using intraoral radiographs. This study assessed the feasibility of using X-ray digital subtraction of the program Regeemy - Image Registration and mosaicking v.0.2.43-RCB (DPI-INPE, Sao Jose dos Campos, SP, Brazil) in periapical radiographs digitized and obtained without the use of standardized rigid during the exposures by registering the event. The selection of control points were performed automatically and in quantity by multiple Reggemy. These points were used as coordinates from which the program aligned the image pair and a third image generated according to the geometrical projection of the reference image. Using Adobe Photoshop ©, we selected the ROI of the images using guides and coordinates. After applying the statistical tests we can conclude that the methodology of this study does not suggest that the subtraction using the program Regeemy is feasible when performed without standardization. It is suggested further studies to evaluate the impact of subtraction radiography with no standardization in clinical diagnosis Mestre

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Geijer, Håkan. "Radiation dose and image quality in diagnostic radiology : optimization of the dose - image quality relationship with clinical experience from scoliosis radiography, coronary intervention and a flat-panel digital detector /." Linköping : Univ, 2001. http://www.bibl.liu.se/liupubl/disp/disp2001/med706s.htm.

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Saez, Daniel Martinez. "Avaliação da influência dos formatos DICOM e JPEG na reprodutibilidade de pontos cefalométricos em Telerradiografia digital em Norma Frontal." Universidade Metodista de São Paulo, 2009. http://tede.metodista.br/jspui/handle/tede/1272.

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Made available in DSpace on 2016-08-03T16:31:14Z (GMT). No. of bitstreams: 1 DANIEL MARTINEZ SAEZ.pdf: 1606570 bytes, checksum: c2773e8408583cb2ada8e4b43508558e (MD5) Previous issue date: 2009-03-31 The digital image on DICOM format request a large store size capability, making difficult the transmission through internet, usually requesting the image compression via JPEG file format. The aim of this study was to evaluate the influence of DICOM and JPEG file formats on Quality Factors 100, 80 and 60, in the reproducibility intra and interexaminer at cephalometrics landmarks identification at digital Frontal Teleradiographies. The sample consists of 120 digital images of Frontal Teleradiographies, obtained from 30 individuals. The 30 original images in DICOM format was converted into a JPEG format on Quality Factors 100, 80 and 60. After blind and random the sample, three calibrated orthodontist marked 18 cephalometric points on each image using a computerized cephalometric program which has in account cephametric points values in a X and Y cartesians coordinates system. At the results, the statistical tests at intraclasses correlations and variant analysis (ANOVA) presents a reproducibility agreement of the cephalometric points on digital Frontal Teleradiographies on intra such as interexaminer, except for points ZL, ZR, AZ, JR, NC, CN on coordinate Y and A6 on coordinate X, independently of file formats. As a conclusion, the file formats DICOM and JPEG on Quality Factors 100, 80 and 60 do not affected the reproducibility intra and interexaminers on a cephalometric landmarks identification.(AU) A imagem digital no formato DICOM requer grande espaço para armazenamento, dificultando o arquivamento e transmissão da imagem via internet, sendo necessária, muitas vezes, a compressão das imagens por meio de formatos de arquivo como o JPEG. O objetivo neste estudo foi avaliar a influência dos formatos DICOM e JPEG, nos Fatores de Qualidade 100, 80 e 60, na reprodutibilidade intra e interexaminador na marcação de pontos cefalométricos em Telerradiografias digitais em Norma Frontal. A amostra consistiu de 120 imagens digitais de Telerradiografias em Norma Frontal, obtidas de 30 indivíduos. As 30 imagens originais, em formato DICOM, posteriormente, foram convertidas para o formato JPEG, nos Fatores de Qualidade 100, 80 e 60. Após cegar e randomizar a amostra, três ortodontistas calibrados marcaram os 18 pontos cefalométricos em cada imagem utilizando um programa de cefalometria computadorizada, que registra as medidas dos pontos cefalométricos em um sistema de coordenadas cartesianas X e Y. Nos resultados, os testes estatísticos de correlações intraclasses e análise de variância (ANOVA) apresentaram concordância de reprodutibilidade dos pontos cefalométricos em Telerradiografias digitais em Norma Frontal, tanto intra como interexaminador, com exceção dos pontos ZL, ZR, AZ, JR, NC, CN na coordenada Y e A6 na coordenada X, independentemente dos formatos de arquivo. Em conclusão, os formatos de arquivo DICOM e JPEG, nos Fatores de Qualidade 100, 80 e 60, não afetaram a reprodutibilidade intra e interexaminador na marcação dos pontos cefalométricos.(AU)

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Christensen, Shane R. "An in vitro comparison of working length accuracy between a digital system and conventional film when vertical angulation of the object is variable." Connect to resource online, 2009. http://hdl.handle.net/1805/1926.

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Thesis (M.S.D.)--Indiana University School of Dentistry, 2009. Title from PDF t. p. (viewed Aug. 21, 2009) Advisor(s): Mychel Vail, Acting Chair of the Research Committee, Joseph Legan, Kenneth Spolnik, Susan L. Zunt, Edwin Parks. Curriculum vitae. Includes abstract. Includes bibliographical references (leaves 109-120).

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Assis, Afonso Celso Souza de [UNESP]. "Estudo da viabilidade do emprego da técnica de subtração radiográfica digital em radiografias periapicais com registro a posteriori." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/98003.

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Made available in DSpace on 2014-06-11T19:29:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-31Bitstream added on 2014-06-13T19:26:45Z : No. of bitstreams: 1 assis_acs_me_sjc.pdf: 596243 bytes, checksum: fb9783652a81f3cb2ec3e7e3c9337fbc (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Apesar de ser uma técnica limitada, a subtração digital é utilizada na Odontologia. A adição do computador e seus algoritmos para equalização de contraste e também correção geométrica, tornou possível a aplicação da subtração radiográfica digital (SRD), utilizando radiografias intrabucais. Neste estudo foi avaliada a viabilidade da utilização da subtração radiográfica digital pelo programa Regeemy – Image Registration and Mosaicking v.0.2.43-RCB (DPI-INPE, São José dos Campos, SP, Brazil) em radiografias periapicais digitalizadas e obtidas sem utilização de padronização rígida durante as exposições por meio de registro a posteriori. A seleção dos pontos de controle foram realizadas de forma automática e em quantidade múltipla pelo Reggemy. Esses pontos serviram como coordenadas a partir das quais o programa alinhou o par de imagens e gerou uma terceira imagem de acordo com a projeção geométrica da imagem de referência. Com o uso do Adobe Photoshop© foram selecionados os ROI das imagens utilizando guias e coordenadas. Depois de aplicados os testes estatísticos foi verificado que a metodologia do presente estudo não permite concluir que a subtração utilizando-se o programa Regeemy é inviável quando realizada sem padronização The digital subtraction has been widely used in dentistry. The addition of computer and its algorithms for equalization of contrast and geometric correction also made possible the application of radiographic digital subtraction (SRD) using intraoral radiographs. This study assessed the feasibility of using X-ray digital subtraction of the program Regeemy - Image Registration and mosaicking v.0.2.43-RCB (DPI-INPE, Sao Jose dos Campos, SP, Brazil) in periapical radiographs digitized and obtained without the use of standardized rigid during the exposures by registering the event. The selection of control points were performed automatically and in quantity by multiple Reggemy. These points were used as coordinates from which the program aligned the image pair and a third image generated according to the geometrical projection of the reference image. Using Adobe Photoshop ©, we selected the ROI of the images using guides and coordinates. After applying the statistical tests we can conclude that the methodology of this study does not suggest that the subtraction using the program Regeemy is feasible when performed without standardization. It is suggested further studies to evaluate the impact of subtraction radiography with no standardization in clinical diagnosis

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Giovanini, Ellen Greves [UNESP]. "Análise densitométrica digital do processo de reparo em dentes de rato reimplantados." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/91434.

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Made available in DSpace on 2014-06-11T19:25:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-11-30Bitstream added on 2014-06-13T20:13:38Z : No. of bitstreams: 1 giovanini_eg_me_araca.pdf: 1544057 bytes, checksum: 1b518f21ba8bc63249a3f29eb78ba402 (MD5) A avulsão dentária é caracterizada pelo completo deslocamento do dente do seu alvéolo e a melhor forma de tratar um dente avulsionado é o seu reimplante. Mesmo diante das melhores circunstâncias os reimplantes tardios falham devido à reabsorção radicular que é detectada apenas durante a avaliação radiográfica. A imagem digital surgiu como um recurso diagnóstico rápido e de fácil utilização sendo considerada precisa. Para diminuir a variabilidade de interpretação é sugerida a análise radiográfica quantitativa por meio da densidade radiográfica. O propósito deste trabalho foi analisar comparativamente o processo de reparo do reimplante dental em ratos utilizando a análise densitométrica no sistema digital Digora. Foram utilizados 30 ratos machos, divididos em 3 grupos de 10 animais, que tiveram seu incisivo superior direito extraído e tratado da seguinte forma: grupo I - reimplante imediato, grupo II - reimplante tardio sem tratamento e o grupo III - reimplante tardio com tratamento da superfície radicular utilizando raspagem do ligamento e fluoreto de sódio. Os animais foram sacrificados após 60 dias do ato operatório, suas maxilas foram separadas e as imagens radiográficas obtidas de forma que sobre cada placa óptica ficassem as duas hemimaxilas (tratada e controle), o penetrômetro de alumínio e a identificação. Foram realizadas medidas de densidade em áreas padronizadas no sistema Digora. Os valores densitométricos encontrados foram submetidos à análise de variância e teste de Tuckey, e análise não paramétrica do número de áreas de reabsorção. Podemos concluir que a análise densitométrica constitui um importante exame complementar para o acompanhamento dos reimplantes uma vez que permitiu a detecção de reabsorção radicular em todos os grupos, cuja ordem decrescente de envolvimento foi o grupo do reimplante tardio sem tratamento... The dental replanted has been considered the best treatment of the tooth avulsion, which is characterized by complete alveolar dislodgment of the tooth. Despite of the adequate clinical situations, the delayed replantation fails due to the root resorption that is detected during the radiographic evaluation. The use of the digital image represent a fast and easy diagnostic resource, furthest more precise. The quantitative radiographic analysis has been suggested to reduce the interpretation variability through the radiographic density. The purpose of this work was to analyze the process of repair of the dental replanted using the digital densitometry in the Digora system. The 30 male rats were divided in 3 groups of 10 animals, and their right superior incisor were extracted and treated agreement with their group: group I - immediate replanted, group II - delayed replanted without treatment and the group III - delayed replanted with treatment of the root surface using fluoride of sodium. The animals were sacrificed after 60 days operative act, your jawbones were separate and the radiographic images obtained so that on each optical plate were the two jawbones (treated and control), the aluminum step wedge and the identification. The radiographic density of radicular standardized area in Digora system was measured. The densitometric values were submitted to the variance analysis and test of Tuckey and analysis non parametric of the number of areas root resoption. We can end that digital densitometry analysis it an important complementary for replanted evaluation once it allowed the detection of root reabsorption in all of the groups, whose decreasing order of involvement was the group of the delayed replanted without treatment, following for the delayed replanted with treatment and last the immediate replanted.

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Moraes, Michelle Bianchi de [UNESP]. "Influência das variações de ângulos de projeção na detecção de reabsorções radiculares linguais e apicais simuladas: comparação entre subtração radiográfica digital e radiografia digital direta." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/105861.

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Made available in DSpace on 2014-06-11T19:35:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-05Bitstream added on 2014-06-13T18:46:28Z : No. of bitstreams: 1 moraes_mb_dr_sjc.pdf: 1197811 bytes, checksum: 257ea85b7a3e332fae697c54b7a1c2a9 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) A reabsorção severa da raiz diagnosticada tardiamente pode acarretar a perda dentaria, e sendo a técnica de subtração radiográfica digital (SDR) um importante recurso para detecção precoce de alterações minerais, este estudo avaliou a eficiência no diagnóstico precoce da reabsorção radicular externa simulada apical e lingual, pela técnica de subtração radiográfica digital (SRD) e radiografia digital (RD). Foram utilizados 14 dentes incisivos de mandíbulas humanas maceradas com reabsorções de diferentes dimensões, simuladas na região apical e lingual, e radiografados com variação de ângulos de projeção. As radiografias foram subtraídas pelo programa Regeemy®, e para avaliação do desempenho dos métodos de diagnóstico, pares de radiografias periapicais e imagens subtraídas foram apresentadas a 2 radiologistas. De acordo com os resultados, não foram observadas diferenças estatisticamente significativas entre os métodos na detecção de reabsorções linguais, independentemente do tamanho da lesão, assim como não houve diferença entre os métodos na detecção de reabsorções apicais, com exceção do examinador 2 com relação a variação angular vertical e horizontal de 100 utilizando o maior nível de desgaste, que apresentou a radiografia digital como método superior na avaliação em relação a subtração radiográfica. E o aumento no nível de desgastes e a menor variação dos ângulos verticais e horizontais permitiram melhor avaliação nas regiões de reabsorções apicais e linguais, para detecção das reabsorções apicais e linguais. Com estes resultados podemos concluir que a subtração radiográfica digital é um exame indicado para detecção de pequenas perdas minerais em radiografias que apresentem pouca ou nenhuma variação nas angulações verticais e horizontais The severe root resorption diagnosed late can lead to tooth loss, and being the technique of digital subtraction radiography (SDR) as an important resource for early detection mineral changes, this study evaluated the efficiency in the early diagnosis simulated external root resorption apical and lingual by the technique of digital subtraction radiography (SRD) and digital radiography (DR). We used 14 human incisors jaw macerated with resorption different sizes, simulated in the apical and lingual, and radiographed with a range of projection angles. The radiographs were subtracted by the program Regeemy ®, and performance evaluation diagnostic methods, pairs intraoral radiographs and subtracted images were presented to two radiologists. According to the results, there were no statistically significant differences between methods in the detection lingual resorption, regardless of lesion size, as there was no difference between the methods in the detection of apical resorption, except the second examiner with respect to variation vertical and horizontal angle of 100 using the highest level of wear, which lodged the digital radiography as a method superior in the evaluation for subtraction radiography. And the increase in the level of wear and less variation vertical and horizontal angles allowed a better assessment resorption in the regions apical and lingual to detect and lingual apical resorption. With these results we conclude that the digital subtraction radiography is a test for the detection of small mineral loss in radiographs showing little or no variation in vertical and horizontal angles

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Lima, Vicente José Muratore de. "\"Estudo prospectivo dos parâmetros periodontais e peri-implantares dos pilares que recebem prótese dento-implanto-suportada\"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/23/23137/tde-30102006-153856/.

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Desde a introdução dos implantes na Odontologia, controvérsias tem havido acerca da propriedade de conectar os implantes a dentes em próteses fixas. Os implantes osseointegrados não apresentam nenhum ligamento periodontal e são mais firmemente ancorados ao osso. A diferença apresentada nesta ancoragem tem levantado preocupações acerca de o implante osseointegrado, por sua firme fixação ao osso, apresentar pouca flexibilidade para dividir as cargas funcionais com os dentes conectados. O presente estudo teve como propósito acompanhar prospectivamente os parâmetros periodontais ? índice gengival, índice de sangramento, profundidade de sondagem e perda de inserção entre o dente pilar de uma prótese dento-implanto-suportada com o dente colateral do mesmo paciente, e também os parâmetros peri-implantares dos implantes que suportam estas próteses - índice gengival; índice de sangramento; profundidade de sondagem e perda de inserção. Para verificar a perda de inserção foi utilizado o recurso da subtração radiográfica da região em que a prótese foi instalada, com tomadas radiográficas efetuadas no momento da instalação da prótese, decorridos seis meses e após 12 meses de uso, com o objetivo de verificar a ocorrência, ou não, de alteração do suporte ósseo peri-implantar. Foram selecionados 12 pacientes com estado de saúde normal, apresentando área posterior de mandíbula edêntula onde estava indicada a reabilitação protética por meio de prótese fixa unindo dente a implante. Estes foram tratados com implante de um estágio de 10 mm padrão da Straumann (ITI), que apresenta um pescoço polido de 2.8mm, onde a porção do implante que permanece intra-óssea apresenta uma superfície tratada, com diâmetro de 4.1mm. O implante foi instalado no espaço onde se localizaria o retentor mais distal da futura prótese parcial fixa, seguindo o protocolo. As radiografias digitais obtidas foram avaliadas num software de subtração radiográfica, Matrox Inspector versão oito, para verificar a alteração da variação de densidade óptica e contraste das radiografias quando superpostas, sendo os valores observados no implante comparados com os critérios de sucessos , amplamente abordados nos estudos verificados. Todos os implantes instalados nos pacientes osseointegraram, não houve registro de alteração óssea ao redor dos mesmos e nos dentes pilares das próteses em avaliações feitas após seis meses e 12 meses. As próteses continuaram clinicamente em excelente estado após 12 meses de avaliação nas análises clínicas e radiográficas. Ainda, de acordo com o teste de Sinais de Postos de ilcoxon, concluiu-se estatisticamente que não houve diferença nos parâmetros peri-implantares de cada paciente durante os períodos analisados (zero, seis meses e 12 meses), bem como quando comparados com os respectivos dentes colaterais. Since the introduction of implants in Dentistry, controversies have arisen about the possibility of connecting implants to teeth in fixed prostheses. Osseointegrated implants do no present any periodontal ligature and are more firmly anchored to the bone. The difference presented by this type of anchorage has led to some concern about the limited flexibility of the osseointegrated implant to share the functional loads with the connected teeth. This study intended to follow-up prospectively the periodontal parameters bleeding index, probing depth between the pillar tooth of an implant supported prosthesis with one control tooth of the same patient and also the implants that support theses prostheses. That is why subtraction radiography of the region in which the prosthesis was placed was used, with radiographs taken at prosthesis placement, after six months and one year of use to verify if the periimplant osseous support had or had not undergone changes. Twelve patients with normal health conditions were selected who presented a posterior area edentulous jaw where a prosthetic rehabilitation by a fixed prosthesis joining tooth to implant was indicated. Patients were treated with an implant of one stage of 10mm standard Straumann (ITI) with a 2.8 mm polished neck, in which the remaining intraosseous portion of the implant has a treated surface of 4.1 mm diameter. The implant was placed in the space where according to the protocol, the more distal retainer of the future fixed partial prosthesis would be located. Digital radiographs were assessed with a subtraction radiography software Matrox Inspector version eight, to corroborate the change of contrast in the radiographs when superimposed, with values observed in the implant compared with the success criteria , widely mentioned in surveyed studies. All implants placed in patients became osseointegrated. There was no record of bone change around them and in the dental pillars of the prostheses at the one year follow-up. Prostheses continue to be in excellent conditions after the one year follow-up based upon clinical and radiographic analyses. Furthermore, in accordance with the Wilcoxon test of matched pairs and signed rank, it was concluded that there was no statistical difference between each group of each patient during the time period analyzed (baseline and one year) as well as when the pillars were compared to their respective controls.

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Grundmann, Ilva Nena Maria. "Digital Radiographic and Magnetic Resonance Imaging of the Normal Equine Foot: a Focus on the Soft Tissue Structures of the Hoof Wall and Sole." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337091737.

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Jorgenson, Todd F. "Comparison of two imaging modalities : F-speed film and digital images for detection of osseous defects in patients with vertical bone defects /." Oklahoma City : [s.n.], 2003.

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Vaz, Sergio Lins de Azevedo 1984. "Exatidão de filtros de imagem na avaliação radiográfica do nível ósseo peri-implantar." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288931.

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Orientador: Paulo Sérgio Flores Campos Texto do capítulo 1 em inglês Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba Made available in DSpace on 2018-08-20T12:07:20Z (GMT). No. of bitstreams: 1 Vaz_SergioLinsdeAzevedo_M.pdf: 1201820 bytes, checksum: c01a9a7bcc2ca60b934986c91f46e192 (MD5) Previous issue date: 2012 Resumo: O objetivo neste trabalho foi identificar a exatidão de alguns filtros de imagem na mensuração do nível ósseo peri-implantar, por meio da radiografia digital. Para isso, vinte implantes de titânio (Titamax, Neodent, Curitiba, PR, Brasil) foram instalados em seis fragmentos de costelas bovinas, nas quais foram criados defeitos do tipo perda óssea. Utilizando um sistema intra-bucal de placas de fósforo (Vista Scan, Dürr Dental, Beitigheim-Bissingen, Alemanha), radiografias periapicais foram realizadas posicionando os implantes segundo a técnica do paralelismo. Após a obtenção das imagens, nove filtros do software DBSWIN foram aplicados: fine, caries 1, caries 2, perio, endo, noise reduction, invert, emboss e sculpture. Um avaliador mensurou as distâncias entre o ombro do implante à porção mais apical do defeito no software Image J. Os defeitos também foram mensurados nas costelas bovinas utilizando um paquímetro digital. O teste não-paramétrico de Friedman comparou os valores obtidos nas imagens com aplicação dos filtros aos encontrados nas imagens originais e nas costelas bovinas, adotando nível de significância de 5%. Os resultados mostraram diferenças estatisticamente significantes para os filtros caries1, caries2, endo e perio (P < 0.05) tanto em relação às imagens originais, quanto em relação às mensurações obtidas com o paquímetro. As mensurações obtidas com as imagens originais, filtros fine e emboss foram mais próximas às obtidas com o paquímetro. Concluiu-se que os filtros fine e emboss foram os mais exatos na mensuração do nível ósseo peri-implantar, sendo equiparáveis às imagens originais. Os filtros caries1, caries2, endo e perio foram os menos exatos, não sendo indicados para este fim Abstract: This study aimed to identify the accuracy of some enhancement filters of an intraoral phosphor-plate system for measuring the simulated periimplant bone level. Twenty titanium implants (Titamax, Neodent, Curitiba, PR, Brazil) were placed into six fragments of bovine ribs and defects simulating bone loss were created. Periapical radiographs were taken with a phosphor-plate system (Vista Scan, Dürr Dental, Beitigheim-Bissingen, Germany) according to the paralleling standard technique, and nine enhancement filters were applied: fine, caries 1, caries 2, perio, endo, noise reduction, invert, emboss and sculpture. An oral radiologist measured on the Image J software the distance from the neck of the implant to the most apical contact of the bone with the implant. The Friedman non-parametric test compared the radiographic measurements to those obtained on the bovine ribs with a digital caliper. The significance level adopted was 5%. The caries1, caries2, endo, and perio filters resulted on measurements statistically different from both the original images and the measures of the digital caliper (P < 0.05). In conclusion, the fine and emboss filters resulted on the most precise filters, with similar measures to the original images. The caries1, caries2, endo, and perio filters were the less accurate for measuring the periimplant bone level Mestrado Radiologia Odontologica Mestre em Radiologia Odontológica

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Hayek, Jorge Elie. ""Avaliação da densidade ótica perimplantar cervical em controle longitudinal de implantes com função oclusal imediata em maxila"." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-11112005-115646/.

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A proposta neste estudo foi avaliar as alterações da densidade ótica do osso alveolar perimplantar cervical em controle longitudinal, por meio de radiografias periapicais digitalizadas de dez pacientes, nos quais foram instalados seis implantes na maxila submetidos à função oclusal imediata, mediante a instalação de uma prótese fixa 24 horas após a cirurgia. Todos os pacientes foram avaliados clinicamente, com exames da análise da freqüência de ressonância, além de controle radiográfico. Foi utilizada a técnica radiográfica intrabucal do parale lismo, com cone longo, sendo que o feixe de raios X incidiu perpendicularmente ao longo eixo do implante. Os controles radiográficos foram realizados na instalação da prótese, após 6 meses e após 12 meses. As radiografias obtidas foram então capturadas por uma câmera de vídeo (preto e branco) por meio de um microscópio ótico (40 vezes de aumento). Devido à ampliação utilizada, os implantes tiveram suas imagens digitalizadas em 2 etapas (metade direita e metade esquerda), sendo consideradas como amostras independentes. Após a sobreposição de um gabarito sobre a imagem, com a finalidade padronizar as áreas a serem estudadas, foram analisadas as densidades óticas na área de interesse osso + implante e na área de controle implante (onde não é esperada alteração) por meio do software ImageLab. Para a correção de possíveis variações na densidade da radiografia e projeção geométrica oriundas da metodologia empregada, foi utilizada uma equação matemática para validar a análise dos dados obtidos. Os resultados mostraram que ocorreu variação percentual da densidade ótica na área de interesse (osso + implante) nos primeiros seis meses (T2) com diminuição de aproximadamente 5% para o lado direito e diminuição de aproximadamente 6% para o lado esquerdo em relação às radiografias iniciais (T1) e após doze meses, a diminuição da densidade ótica estabilizou-se, não sendo encontradas alterações estatisticamente significantes em relação ao período correspondente entre T2 (seis meses) e T3 (doze meses). Os resultados da análise digital das radiografias periapicais demonstraram coincidência com os resultados da análise da freqüência de ressonância e exame clínico dos implantes e demonstraram um aspecto compatível com o sucesso dos implantes osteointegrados com função imediata na maxila. The aim in this study was the evaluation of the variations of the perimplantar optical bone density at the cervical region in a longitudinal control, by the use of digitized radiographs of ten patients, who received six implants installed in the maxilla and submitted to immediate occlusion function, through fixed prosthesis installed 24 hours after the surgery. All the patients were observed in clinical control, with resonance frequency analysis and also radiographic control. It was performed a intraoral radiograph using the paralleling technique, with the long cone and the beam of x-ray aimed perpendicular to the long axis of the implant. The radiographic controls were done at the time of the installation of the prosthesis, after six months and after twelve months after the first control. The obtained radiographs were captured by a black and white video camera by an optical microscope (40 times of magnification). Due to the utilized magnification, the implants have their images digitized in two steps: half right and half left, and they were considered as independent samples. After the superimposition of a standardized pattern, to help the standardization of the areas of the study, it was analyzed the optical density at the areas of interest bone + implant and at areas of control bone (where it is not hope changes) through the software ImageLab. To correct possible variations of the effect of the absence of standardization of the geometric projection and the radiographic density, it was realized a mathematic equation and it was obtained a correction factor of density in order to compensate. The results sho wed that there were percentage variation of the optical density at the area of interest (bone + implant) at six months (T2) showed a decreased of about 5% for the right side and showed a decreased of about 6% for the left side when analyzed the first control and after twelve months no significant statistical difference was observed between the T2 period (six months) and T3 period (twelve months). The results of digital analysis from the intraoral radiographs showed as the same as the results of resonance frequency analysis and the clinic examination of the implants and showed a success of implants installed in the maxilla with immediate occlusion function.

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Bittar-Cortez, Juliana Araujo. "Radiografia digital e a tecnica de subtração no monitoramento da desmineralização e remineralização do esmalte dentario." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288985.

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Orientador: Francisco Haiter Neto Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba Made available in DSpace on 2018-08-10T07:50:35Z (GMT). No. of bitstreams: 1 Bittar-Cortez_JulianaAraujo_D.pdf: 5858192 bytes, checksum: 3d3d3c7dbc08b34e4b7c483e7316bd88 (MD5) Previous issue date: 2008 Resumo: O objetivo deste estudo in vitro foi comparar dois protocolos de remineralização em lesões de cárie no esmalte dentário, avaliados por meio de análises de cálcio (Ca) e fósforo (Pi), dureza do esmalte, microscopia de luz polarizada e subtração radiográfica digital (SRD); avaliar a viabilidade da utilização de dois diferentes sistemas de radiografias digitais, placa PSP (photostimulable storage phosphor) e sensor CMOS (complementary metal oxide semicondutor), no diagnóstico de desmineralizações, e a acurácia das radiografias digitais convencionais (RDC) e três métodos de SRD (linear, avançada e logarítmica) no diagnóstico de mudanças minerais; e comparar o ruído e reprodutibilidade das imagens de SRD lineares e logarítmicas produzidas a partir de dois sistemas de radiografias digitais. Para isso, lesões de cárie artificiais foram criadas em 100 superfícies proximais de dentes hígidos. Vinte dentes foram mantidos como controle e oitenta foram submetidos a dois diferentes protocolos de remineralização em 4 e 8 semanas, com a contínua imersão em saliva artificial e um tratamento adicional com flúor. Radiografias digitais foram realizadas antes e depois dos protocolos de remineralização. Cinco examinadores avaliaram a desmineralização e as mudanças minerais nas RDC, dispostas lado a lado, e três métodos da SRD. As análises de Ca / Pi e a colocação dos dentes na solução remineralizante foram considerados como padrão ouro. A média dos tons de cinza e o desvio padrão (DP) no histograma foram também mensurados. As concentrações de Ca e Pi na saliva artificial após os tratamentos foram significativamente menores do que a solução original (p<0,05); e por meio da SRD foi possível verificar diferenças entre as imagens. Entretanto, o teste de dureza e a microscopia de luz polarizada não detectaram nenhuma alteração. O sistema CMOS foi significativamente mais acurado do que a sistema PSP no diagnóstico da desmineralização e mudanças minerais, assim como a SRD linear no diagnóstico de mudanças minerais. Também foram estatisticamente diferentes os valores da média dos níveis de cinza e do DP entre os dois sistemas. Foi concluído que (a) o tratamento adicional de flúor promoveu valores maiores de ganho mineral; (b) a análise de Ca / Pi na saliva artificial foi o método mais sensível na avaliação de alteração mineral; (c) a imagem de SRD linear é um método válido na detecção do aumento de intensidade, como sinal de ganho mineral; e (d) as imagens de SRD utilizando as placas PSP tiveram um menor ruído do que nas imagens geradas pelo sensor CMOS Abstract: The aim of this in vitro study was to compare two remineralization protocols of artificial carious lesions in enamel, evaluated by Calcium (Ca) and Phosphorus (Pi) analysis, cross-section hardness test, polarized light microscopy and digital subtraction images (DSR); to assess the feasibility of using two different systems of digital radiography, photostimulable storage phosphor (PSP) plate and complementary metal oxide semiconductor (CMOS) sensor on the demineralization diagnosis, and the accuracy of digital conventional radiographs (DCR) and three methods of DSI (linear, advanced and logarithmic) on mineral changes diagnosis; and, to compare noise and reproducibility in linear and logarithmic DSI produced from two digital radiography systems. Artificial caries-like lesions on 100 approximal surfaces of sound teeth were produced. Twenty teeth were kept as control and eighty teeth were subjected to two different remineralization protocols for 4 and 8 weeks, with continuous immersion in artificial saliva, and additional fluoride treatment. Digital radiographs were taken before and after the remineralization protocols. Five examiners assessed demineralization and mineral changes on DCR, placed side by side, and three methods of DSI. Ca / Pi analysis and the placement of the teeth on the remineralization solution was the gold standard. The mean shades of gray and the standard deviation (SD) of the histogram were also assessed. The concentrations of Ca and Pi in the artificial saliva after the treatments were significantly lower than the original solution (p<0.05); and DSR showed differences between the images. However, the Hardness test and polarized light microscopy did not detect any changes. CMOS system was significantly more accurate than PSP system on demineralization and mineral changes diagnosis, and also linear DSR on mineral changes diagnosis. It was also statistically significant different the values of mean shades of gray and SD between both systems. It was concluded that (a) the additional Fluoride treatment provided higher values of mineral gained; (b) Ca / Pi analysis in the artificial saliva were the most sensitive method of mineral change evaluation; (c) linear DSI is a valuable method to disclose an intensity increase, as a sign of mineral gained; and (d) DSR images created from PSP plates had less noise than images produced from CMOS sensor Doutorado Radiologia Odontologica Doutor em Radiologia Odontológica

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Monti, Lira Marcela [UNESP]. "Estudo radiográfico digital e densitométrico em mandíbulas de suínos, submetidas a osteotomia com brocas de alta e baixa rotação, com refrigeração líquida." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/91430.

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Made available in DSpace on 2014-06-11T19:25:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-09Bitstream added on 2014-06-13T19:52:59Z : No. of bitstreams: 1 monti_lm_me_araca.pdf: 287560 bytes, checksum: 074e03765d9ead5baba4ea3ffcdf36ee (MD5) Universidade Estadual Paulista (UNESP) Avaliou-se, por meio de exames radiográficos digitais e densitométricos, a influência do tipo de instrumento rotatório para corte, no processo de reparação óssea após osteotomias em mandíbula de suíno em tempos controlados. Foram utilizados para o estudo oito suínos da raça Large White, com peso corpóreo inicial variando de 25 a 30 Kg. Dois cortes transversais do meio à base de mandíbula direita foram realizados, um por meio de instrumento rotatório de alta rotação e o outro pela ação da baixa rotação, ambos com irrigação líquida. Após períodos pré-estabelecidos (7, 28, 60 e 90 dias) os animais foram sacrificados e suas mandíbulas retiradas para estudos radiográficos digitais diretos e indiretos, pelo sistema DIGORA e ODR e de densitometria óptica por imagens radiográficas pelo sistema CROMOX. Nos períodos iniciais (7 e 28 dias) as densitometrias foram maiores na região das osteotomias realizadas com alta rotação e nos períodos finais (60 e 90 dias) as densitometrias foram maiores nas osteotomias feitas com baixa rotação, indicando uma melhor reparação óssea final quando do uso de baixa rotação. A análise qualitativa do processo de reparação foi feita pelo sistema ODR, que possibilitou a obtenção de imagens digitais tridimensionais e coloridas, permitindo comparação das espessuras ósseas com as de uma cunha de alumínio, evidenciando que aos sessenta dias a reparação óssea estava aparentemente completa. Os histogramas do DIGORA apontaram valores de médias de nível de cinza nas áreas de osteotomia, evidenciando uma maior quantidade de tons de cinza nas osteotomias de alta rotação nos primeiros tempos, e nas osteotomias com baixa-rotação nos tempos finais. It was evaluated, through digital and densitometric radiographic exams, the influence of the type of rotating instrument for cut, in the process of bony repair after osteotomy in swine jaw in controlled times. They were used for the study eight Large White swines, with initial corporal weight varying from 25 to 30 Kg. Two traverse cuts of the middle to the base of right jaw were accomplished, one through rotating instrument of high rotation and the other for the action of the low rotation, both with liquid irrigation. After established periods (7, 28, 60 and 90 days) the animals were sacrificed and your mandibles retired for direct and indirect digital radiografic studies, for the DIGORA and ODR systems and of optical densitometry for radiographic images for the CROMOX system. In the initial periods (7 and 28 days) the densitometry were larger in osteotomy areas accomplished with high rotation and in the final periods (60 and 90 days) the densitometry were larger in the osteotomy done with low rotation, indicating a better final bony repair when of the use of low rotation. The qualitative analysis of the repair process was made by the ODR system, that made possible obtaining three-dimensional and colored digital images, allowing comparison of the bony thickness with the one of a wedge of aluminum, evidencing that to the sixty days the bony repair was apparently complete. The histograms of DIGORA pointed values of the averages of ash tones in the osteotomy areas, evidencing a larger amount of ash tones in the osteotomy of high rotation in the first times, and in the osteotomy with low-rotation in the final times.

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26

Liedke, Gabriela Salatino. "Influência da presença de materiais metálicos na capacidade diagnóstica de diferentes métodos por imagem - radiografia convencional, radiografia digital e tomografia computadorizada de feixe cônico - investigação in vitro." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/102539.

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O objetivo desta tese foi avaliar a interferência da presença de materiais metálicos na imagem radiográfica e tomográfica por meio da análise da adaptação marginal de restaurações e coroas metálicas. Esta investigação resultou em 3 artigos: uma revisão sistemática da literatura para identificar o estado da arte com relação ao uso dos métodos radiográficos; um estudo in vitro comparando o desempenho do filme radiográfico convencional e dos sistemas digitais VistaScan Dürr Dental, Digora Classic Soredex e Express Instrumentarium – com e sem o emprego de filtros para o pós processamento da imagem; e um estudo in vitro avaliando o processamento das imagens da TCFC – utilizando diferentes espessuras de reconstrução. Na revisão sistemática foram incluídos 14 estudos, sendo classificados de baixa ou moderada qualidade, de acordo com os critérios QUADAS de classificação. Na investigação radiográfica (artigo 2), os maiores valores de sensibilidade (0,67 0,83), especificidade (0,81 0,92) e acurácia (0,73 0,86) foram obtidos com radiografias convencionais e imagens digitais originais. Na avaliação tomográfica (artigo 3), os valores da aucROC variaram de 0,60 a 0,72, sendo que o limite inferior do intervalo de confiança mostrou-se abaixo ou muito próximo da linha de referencia. Frente aos resultados, conclui-se que imagens radiográficas originais (convencionais ou digitais) devem ser preferidas para a avaliação de dentes com restaurações metálicas. Quanto à TCFC, mesmo quando se aumenta a espessura de reconstrução da imagem e diminui-se o artefato, ainda assim não há melhora na acurácia do diagnóstico. The aim of this thesis was to evaluate the interference of the presence of metallic materials on radiographic and tomographic image by assessing misfits tooth and restoration in metal-restored teeth. This investigation resulted in three articles: a systematic review of the literature to identify the state of the art on the use of radiographic methods; an in vitro study comparing the performance of conventional film and digital phosphor plate systems Vistascan Dürr Dental, Digora Classic Soredex and Instrumentarium Express – exported as original images and with the use of post processing filters; and an in vitro study evaluating the post-processing of CBCT images – using diverse reconstruction thicknesses. The systematic review retrived 14 studies, classified as low- / moderate quality based on QUADAS criteria. For radiographic evaluation (article II), higher sensitivity (0.67 0.83), specificity (0.81 0.92) and accuracy (0.73 0.86) values were obtained with conventional and digital original images. For tomographic evaluation (article III), mean aucROC ranged from 0.60 to 0.72, and the analysis of the 95% CI showed the lower bound of the curve bellow or very close to the reference line. Based on the results, it is concluded that original images (conventional or digital) should be preferred for the assessment of teeth with metal restorations. Considering CBCT images, even thought increased reconstruction thickness decreased perceived artifact, it did not improve diagnosis accuracy.

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Grantham, Stephen Gary. "Digital speckle radiography." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619648.

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Beghini, Ana Cristina da Rocha Duque. "Avaliação da radiopacidade de diferentes sistemas cerâmicos livres de metal." Universidade Federal de Juiz de Fora, 2011. https://repositorio.ufjf.br/jspui/handle/ufjf/2061.

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Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-13T15:19:13Z No. of bitstreams: 1 anacristinadarochaduquebeghini.pdf: 604681 bytes, checksum: 77222c9c607ebf796ce7a6f000f0c9c1 (MD5) Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:58:18Z (GMT) No. of bitstreams: 1 anacristinadarochaduquebeghini.pdf: 604681 bytes, checksum: 77222c9c607ebf796ce7a6f000f0c9c1 (MD5) Made available in DSpace on 2016-07-13T16:58:18Z (GMT). No. of bitstreams: 1 anacristinadarochaduquebeghini.pdf: 604681 bytes, checksum: 77222c9c607ebf796ce7a6f000f0c9c1 (MD5) Previous issue date: 2011-05-02 No presente estudo avaliou-se a radiopacidade de restaurações cerâmicas livres de metal de forma objetiva, subjetiva e por meio de MEV/EDS. Foram utilizadas as cerâmicas: Noritake EX-3 (Noritake), VM13 (Vita), IPS Empress II (Ivoclar Vivadent), IPS E.max ZirPress (Ivoclar Vivadent) e PM9 (Vita). Para a avaliação objetiva foram confeccionados cinco corpos de prova nas espessuras de 1, 2, 3 e 4 mm, que foram radiografados juntamente com uma escala de densidade e uma secção dental, utilizando-se sistema digital direto. As imagens radiográficas foram submetidas à leitura de densidade óptica. Para a avaliação subjetiva foram confeccionados phantoms, simulando a parte posterior das arcadas dentárias, no qual dois dentes de cada phantom foram submetidos a preparos inlay, restaurados com as cerâmicas estudadas, e radiografados pela técnica interproximal. Essas radiografias foram avaliadas por três grupos de examinadores: cirurgiões-dentistas, radiologistas e protesistas. Para a análise dos elementos químicos que dão características de radiopacidade aos materiais, foi realizada avaliação pelo MEV/EDS. Os resultados da avaliação objetiva indicaram diferenças significativas entre as radiopacidades das cerâmicas estudadas. Para 1 e 2 mm de espessuras todas as cerâmicas apresentaram radiopacidade superior a da dentina e inferior a do esmalte. A cerâmica Noritake EX3 apresentou maior radiopacidade em todas as espessuras. Não se puderam constatar, nas avaliações simulando condições clínicas, as diferenças de radiopacidades observadas na avaliação objetiva. O grupo dos cirurgiões-dentistas apresentou a menor acurácia diagnóstica quando comparados aos grupos de especialistas, sendo que os radiologistas apresentaram a maior acurácia diagnóstica para cerâmica (0,57). Independente do grupo de avaliadores, não foi possível a distinção radiográfica entre cerâmicas livre de metal e compósitos. O resultado da avaliação dos materiais pelo MEV/EDS indicou como possíveis elementos radiopacificadores: bário para as cerâmicas Noritake EX-3 (2,19%), VM13 (1,04%), PM9 (0,70%) e IPS Empress II (0,70%); e zinco (4,50%) e cério (1,45%) para a cerâmica IPS E.max ZirPress. The aim of this study to evaluate the radiopacity of metal-free ceramic restorations in an objective, subjective and by SEM and EDS. Ceramics were used: Noritake EX-3 (Noritake), VM13 (Vita), IPS Empress II (Ivoclar Vivadent), IPS e.max ZirPress (Ivoclar Vivadent) and PM9 (Vita). For the objective evaluation were prepared five specimens with thickness of 1, 2, 3 and 4 mm, which were radiographed with a aluminum step and a dental section, using direct digital system. The radiographic images were submitted to the reading of optical density. For subjective evaluation were fabricated phantoms, simulating the back of the dental arches, in which two teeth of each phantom received an inlay preparation, were restored with the studied ceramics, and were x-rayed by the interproximal technique. These radiographs were evaluated by three groups of examiners, dentists, radiologists, and prosthetists. To analyze the chemical elements that provide radiopacity characteristics of the materials, evaluation was performed by SEM and EDS. The results of objective evaluation indicated significant differences between the radiopacity of the studied ceramics. For 1 and 2 mm in thickness and the ceramics were all higher radiopacity dentin and enamel below. Ceramics Noritake EX3 showed higher radiopacity in all thicknesses. There was evident on the evaluations simulating clinical conditions, the differences observed in the radiopacity of objective evaluation. The group of dentists had a lower diagnostic accuracy when compared to groups of specialists, and radiologists had the highest diagnostic accuracy for ceramics (0.57). Independent group of evaluators was not possible to distinguish between X-ray and metal-free ceramic composites. The result of evaluation of materials by SEM and EDS indicated as possible elements radiopacifiers barium to ceramic Noritake EX-3 (2.19%), VM13 (1.04%), PM9 (0.70%) and IPS Empress II (0.70%) and zinc (4.50%) and cerium (1.45%) for the ceramic IPS E.max ZirPress.

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Klein, Caroline Gugisch. "Avaliação da arquitetura óssea trabecular por meio de processamento de imagem digital em radiografias panorâmicas." Centro Federal de Educação Tecnológica do Paraná, 2005. http://repositorio.utfpr.edu.br/jspui/handle/1/102.

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Este trabalho teve como objetivo modificar um algoritmo de esqueletização e criar outro para quantificar imagens radiográficas. Foi proposto um tratamento digital em radiografias panorâmicas de 50 voluntárias diagnosticadas como osteoporóticas e não osteoporóticas em um estudo anterior. Para verificar a validade deste recurso digital, foi elaborado um questionário que juntamente com as radiografias foi distribuído entre quinze examinadores radiologistas. Estes analisaram de forma subjetiva 99 imagens, respondendo quais os critérios adotados para a avaliação da arquitetura óssea trabecular. Os dados obtidos no questionário aplicado e no tratamento digital das imagens foram submetidos à análise descritiva para verificar o nível de concordância nas hipóteses de diagnóstico e definir um padrão ouro. Foi construída uma curva ROC, para verificar o ponto de corte e estabelecer qual filtro de Gauss era o melhor, com raio variável de 30, 35, 40, 45 ou 50. O filtro escolhido foi o de raio 30, pois apresentou melhor especificidade (94,3%), mesmo tendo uma baixa sensibilidade (50%). Os níveis de concordância entre os examinadores ficaram abaixo de 80%. Contudo foi registrada alta significância entre os dados percentuais de pontos pretos e de pontos terminais (p<0.001). O processamento de imagens através da esqueletização em radiografias panorâmicas pode tornar-se um valioso recurso para os cirurgiões-dentistas. The purpose of the present work was to modify a skeletonization algorithm and to create an algorithm to quantify radiographic images. A panoramic radiographic digital treatment of 50 volunteers diagnosed as otheoporotics and non-ostheoporotics in a previous work was done. In order to verify the validity of the digital resource, a questionnaire was elaborated that along with the radiographies was distributed among 15 radiologists. The examiners analyzed in a subjective way 99 images, responding which criteria were adopted for the evaluation of the trabecular bone architecture. The data obtained in the applied questionnaire and in the digital image treatment were submitted to a descriptive analysis in order to verify the agreement in the diagnostic hypothesis and to define a golden standard. A ROC curve was built to check the cut point and to establish which Gauss filter was the best, with a variable ratio of 30, 35, 40, 45, or 50. The ratio 30 filter was chosen since it presented the best specificity (94.3%), even having a low sensibility (50%). The agreement levels among the examiners were below 80%. However a high significance among the percentage of black points was registered (p<0.001). The method of image processing trough the skeletonization in panoramic radiographies can become a valuable support for the dentist-surgeons.

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30

Mason, Nicholas Andrew. "The generation of a digital phantom for testing of digitally reconstructed radiographs." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000480.

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Packer, McKay Barlow. "Comparison of treatment planning decisions when combining CBCT and digital radiography verses digital radiography alone." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4140.

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Cone beam computed tomography (CBCT) is the recommended imaging modality of choice for evaluating previous endodontic treatment (1). The aim of this study was to compare treatment planning decisions made when evaluating previous endodontic treatment to determine if treatment planned and projected prognosis differs when digital radiography is used alone or in combination with CBCT. A retrospective chart review was conducted. Patients for whom a CBCT was taken were included in the study. Twenty-eight patients qualified. Patient’s periapical digital radiographs (Dexis©) were evaluated by 2 calibrated endodontists, a treatment plan was identified and a prognosis was projected. Later the same radiographs were viewed with CBCT scan. The CBCT provided significant information 75% of the time. CBCT provided the only information for an accurate diagnosis 17% of the time. Prognosis changed 38% of the time when CBCT was added. An unfavorable or questionable prognosis changed to favorable 30% of the time.

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32

SILVA, Janaína Benfica e. "Avaliação do processo de raparo de lesões periopicais pós-tratamento endodôntico por meio de subtração digital radiográfica." Universidade Federal de Goiás, 2006. http://repositorio.bc.ufg.br/tede/handle/tde/1383.

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Made available in DSpace on 2014-07-29T15:22:00Z (GMT). No. of bitstreams: 1 Parte 1.pdf: 1874528 bytes, checksum: 7e46501ade5b782c1d4f3f9926c18a43 (MD5) Previous issue date: 2006-11-30 Control of the process of repair or progression of periapical lesions after endodontic treatment is monitored by conventional or digital radiography. In this research digital subtraction radiography (DSR) was used that uses the subtraction of images longitudinally, in which the change in the alveolar bone is visualized against a uniform gray background. The objectives of this study were: (1) to evaluate the repair process of periapical lesions after endodontic treatment by using DSR; (2) to quantify by means of point/pixel (picture element), area (histogram) and linear measures (profile line), the gain or loss of mineral density in the area of the lesion, using the average of the pixel values; (3) to compare the diagnostic information, suggestive of the repair process, obtained through a subjective evaluation of DSR with a conventional radiographic evaluation and digitalized image and (4) to evaluate the contribution of DSR to an early identification of the repair of periapical lesions after endodontic treatment. The sample consisted of twelve patients with a total of seventeen periapical lesions. The x-rays were digitalized and submitted to DSR using DSR software. The pixel values of the subtracted images were determined by using Image Tool software. Both the conventional x-rays as well as the digitalized and subtracted images were qualitatively evaluated. The results showed a gain in mineral density with a meandp of 133.495.17, 130.275.77 and 129.414.46 for the points/pixel, histogram and profile line tools, respectively. In the evaluation of numerical gain Pearson s Coefficient of Correlation (r) presented these values: mean of points/histogram = 0.746; mean of points/profile line = 0.724 and histogram/profile line = 0.860. When the numerical values were transformed into percentile gain meandp of 0.674.01, 1.214.33 and 1.163.36 were obtained for the points/pixels, histogram and profile line tools, respectively. In the evaluation of the percentile gain Spearman s Coefficient of Correlation (rs) showed the following values: mean of points/histogram = 0.697; mean of the points/profile line = 0.646 and histogram/profile line = 0.844. In the qualitative analysis, the frequency of success in the ordering of the correct sequence of the repair process using conventional radiography, digitalized image and DSR was 37.3%, 31.4% and 31.4%, respectively. One concluded, therefore, that: (1) the process of repair of periapical lesions after endodontic treatment can be evaluated quantitatively by means of longitudinal analysis using DSR; (2) any one of the three tools can be used to quantify the repair, considering that correlation exists between the time of repair and the increase of the value of pixel; (3) the comparative evaluation between the subjective methods using conventional radiography, digitalized image and SDR, it showed that all had been capable to evidence the process of repair of periapical lesions from the first radiography (15 days), not having difference between them and (4) the quantitative evaluation by SDR obtained to after evidence the beginning of the repair with 15 days the beginning of the endodontic treatment, even so this repair was really effective from 105 days after the beginning of the endodontic treatment. O controle do processo de reparo ou progressão de lesões periapicais pós-tratamento endodôntico é monitorado pelo exame radiográfico convencional ou digital. Nesta pesquisa foi utilizada a subtração digital radiográfica (SDR), que utiliza a subtração de imagens longitudinalmente, na qual a mudança no osso alveolar é visualizada contra um plano de fundo (background) cinza homogêneo. Os objetivos desse estudo foram: (1) avaliar o processo de reparo de lesões periapicais pós-tratamento endodôntico por meio de SDR; (2) quantificar por meio de ponto/pixel (picture element), área (histograma) e medida linear (perfil linha) na área da lesão, o ganho ou perda de densidade mineral por meio da média dos valores dos pixels; (3) comparar as informações diagnósticas, sugestivas do processo de reparo, obtidas por meio da avaliação subjetiva da SDR com a avaliação radiográfica convencional e imagem digitalizada; e (4) avaliar a contribuição da SDR na identificação precoce do reparo de lesões periapicais pós-tratamento endodôntico. A amostra constituiu-se de doze indivíduos totalizando dezessete lesões periapicais. As radiografias foram digitalizadas e submetidas à SDR utilizando o programa DSR. As imagens subtraídas tiveram os valores de pixel determinados utilizando o programa Image Tool. Tanto as radiografias convencionais quanto as imagens digitalizadas e subtraídas foram avaliadas qualitativamente. Os resultados evidenciaram ganho de densidade mineral com médiadp de 133,495,17; 130,275,77; 129,414,46 para as ferramentas ponto/pixel; histograma e perfil linha respectivamente. Na avaliação do ganho numérico o Coeficiente de Correlação de Pearson (r) mostrou valores de: média dos pontos/ histograma = 0,746; média dos pontos/ perfil linha = 0,724 e histograma/ perfil linha = 0,860. Quando os valores numéricos foram transformados em ganho percentual foram obtidas médiadp de 0,674,01; 1,214,33; 1,163,36 para as ferramentas ponto/pixel; histograma e perfil linha respectivamente. Na avaliação do ganho percentual o Coeficiente de Correlação de Spearman (rs) mostrou valores de: média dos pontos/ histograma = 0,697; média dos pontos/ perfil linha = 0,646 e histograma/ perfil linha = 0,844. Na análise qualitativa, a freqüência de acertos na ordenação da seqüência correta do processo de reparo usando radiografia convencional, imagem digitalizada e SDR foi de 37,3%; 31,4% e 31,4% respectivamente. Concluiu-se, portanto, que: (1) o processo de reparo de lesões periapicais pós-tratamento endodôntico pode ser avaliado quantitativamente por meio de análise longitudinal com SDR (2) qualquer uma das três ferramentas pode ser utilizada para quantificar o reparo, considerando que existe correlação entre o tempo de reparo e o aumento do valor de pixel; (3) a avaliação comparativa entre os métodos subjetivos, usando radiografia convencional, imagem digitalizada e a SDR, mostrou que todos foram capazes de evidenciar o processo de reparo de lesões periapicais desde a primeira radiografia (15 dias), não havendo diferença entre eles e (4) a avaliação quantitativa por meio de SDR conseguiu evidenciar o início do reparo com 15 dias após o início do tratamento endodôntico, embora esse reparo fosse realmente efetivo a partir de 105 dias após o início do tratamento endodôntico.

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33

Xiao, Xinhua. "Automated Defect Recognition in Digital Radiography." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439309683.

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34

Maschio, Maria Celeste. "Performance evaluation of detector for digital radiography." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8317/.

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Lo scopo di questo lavoro è la caratterizzazione fisica del flat panel PaxScan4030CB Varian, rivelatore di raggi X impiegato in un ampio spettro di applicazioni cliniche, dalla radiografia generale alla radiologia interventistica. Nell’ambito clinico, al fine di una diagnosi accurata, è necessario avere una buona qualità dell’immagine radiologica mantenendo il più basso livello di dose rilasciata al paziente. Elemento fondamentale per ottenere questo risultato è la scelta del rivelatore di radiazione X, che deve garantire prestazioni fisiche (contrasto, risoluzione spaziale e rumore) adeguati alla specifica procedura. Le metriche oggettive che misurano queste caratteristiche sono SNR (Signal-to-Noise Ratio), MTF (Modulation Transfer Function) ed NPS (Noise Power Spectrum), che insieme contribuiscono alla misura della DQE (Detective Quantum Efficiency), il parametro più completo e adatto a stabilire le performance di un sistema di imaging. L’oggettività di queste misure consente anche di mettere a confronto tra loro diversi sistemi di rivelazione. La misura di questi parametri deve essere effettuata seguendo precisi protocolli di fisica medica, che sono stati applicati al rivelatore PaxScan4030CB presente nel laboratorio del Centro di Coordinamento di Fisica Medica, Policlinico S.Orsola. I risultati ottenuti, conformi a quelli dichiarati dal costruttore, sono stati confrontati con successo con alcuni lavori presenti in letteratura e costituiscono la base necessaria per la verifica di procedure di ottimizzazione dell’immagine radiologica attraverso interventi sul processo di emissione dei raggi X e sul trattamento informatico dell’immagine (Digital Subtraction Angiography).

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Rivetti, Di Val Cervo Stefano <1975&gt. "Performance evaluation of detectors for digital radiography." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3611/.

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To date the hospital radiological workflow is completing a transition from analog to digital technology. Since the X-rays digital detection technologies have become mature, hospitals are trading on the natural devices turnover to replace the conventional screen film devices with digital ones. The transition process is complex and involves not just the equipment replacement but also new arrangements for image transmission, display (and reporting) and storage. This work is focused on 2D digital detector’s characterization with a concern to specific clinical application; the systems features linked to the image quality are analyzed to assess the clinical performances, the conversion efficiency, and the minimum dose necessary to get an acceptable image. The first section overviews the digital detector technologies focusing on the recent and promising technological developments. The second section contains a description of the characterization methods considered in this thesis categorized in physical, psychophysical and clinical; theory, models and procedures are described as well. The third section contains a set of characterizations performed on new equipments that appears to be some of the most advanced technologies available to date. The fourth section deals with some procedures and schemes employed for quality assurance programs.

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Stamatakis, Harry Charalabos. "Physical and psychophysical properties of digital intraoral radiography /." Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3799-0/.

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Ricke, Jens. "Über die Optimierung von Waveletalgorithmen für die verlustbehaftete Kompression digitaler Röntgenbilddaten." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2001. http://dx.doi.org/10.18452/13751.

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Ziel: Eine Optimierung medizinischer Bilddatenkompression. Evaluation des Einflusses unterschiedlicher Filter auf die Bildqualität waveletkomprimierter Röntgenbilder. Material und Methode: Im Rahmen von Vorstudien Optimierung der digitalen Bildbefundung anhand von ROC-Analysen. Auswahl geeigneter Kompressionsverfahren durch methodischen und ROC-gestützten Vergleich von Wavelet- mit fraktaler und JPEG-Kompression. Im Rahmen der Hauptstudie ROC-basierter und statistischer Vergleich von 4 unterschiedlichen Waveletfiltern verschiedener Komplexität mittels Prüfkörper für niedrigfrequente, gemischt-frequente und hochfrequente Bildinformation im schwellenwertnahen Bereich. Ergebnisse: Durch Einsatz unterschiedlicher Filter insbesondere im Niedrigfrequenzbereich entstehen signifikante Unterschiede des Rekonstruktionsergebnisses der Röntgenbilder. Trotz eines partiell uneinheitlichen Ergebnisses der visuellen Analyse fanden sich Vorteile für komplexere Filter. Für Details im hochfrequenten Bereich finden sich kaum signifikante Unterschiede. Schlußfolgerungen: Die durch die ROC-Analyse erhobenen Ergebnisse korrelierten in keiner Weise mit den gleichzeitig mathematisch erhobenen PSNR-Werten. Ursache hierfür ist, daß die Reduktion des Bildrauschens durch die Waveletkompression in der PSNR als negative Einflußgröße abgebildet wird. Bei medizinischen Röntgenbildern führt jedoch die Minimierung des Bildrauschens zu einer erhöhten Erkennbarkeit von Details insbesondere im schwellenwertnahen Bereich. Entsprechend verbesserten sich die Ergebnisse der schwellenwertnah durchgeführten ROC-Analyse ungleichsinnig zu den PSNR-Werten. Eine detaillierte Beschreibung des Einflusses der Komplexität von Waveletfiltern auf die Rekonstruktionsqualität medizinsicher Bilder findet sich im Diskussionsteil der Studie. Aim: Optimisation of medical image compression. Evaluation of wavelet-filters for wavelet-compression. Materials and methods: Optimisation of image review applying ROC analysis. Analysis of medical image compression methods comparing wavelet-compression, fractal compression and JPEG by ROC analysis. Evaluation of 4 different wavelet-filters with different complexity applying phantoms for low frequency, high and mixed frequency information. Results: Application of filters with different complexity results in significant variations in the quality of image reconstruction after compression specifically in low frequency informatiin. Filters of high complexity proved to be advantagous despite of heterogenous results during visual analysis. For high frequency details, complexity of filters did not prove to be of significant impact on image quality after reconstruction. Conclusions: Results of ROC analysis did not correspond with PSNR values. Reduction of image noise in reconstructed images by wavelet-filtering is expressed negatively in PSNR values. In medical images, reduction of image noise enhances detection specifically of low contrast details. A detailed discussion of the influence of filter complexity on the reconstruction quality of medical images can be found in the discussion section of the study.

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Gobbi, David G. "A high-pressure gas microstrip detector for digital radiography." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ27049.pdf.

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Hunter, David MacKenzie. "Digital radiography by laser-scanned readout of amorphous selenium." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ45465.pdf.

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Pineda, Fortin Angel. "Detection-theoretic evaluation in digital radiography and optical tomography." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280094.

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This dissertation explores the application of objective assessment of image quality (OAIQ) to hardware evaluation for both linear shift-variant and nonlinear imaging systems. We define our task to be the detection of a known signal in either a uniform or structured background. In particular, we study the detection of signals in digital radiography and optical tomography. In digital radiography, current figures of merit are based on stationarity assumptions on the data. The Hotelling observer as we compute it does not make such assumptions. We quantify, from a detection-theoretic perspective, the errors incurred by using stationarity assumptions for nonstationary digital data. We find that by using Monte Carlo methods, the Hotelling observer carries over to the nonlinear setting, and we use it to study spatially varying detectability in optical tomography. In optical tomography there are several data types that can be used to detect signals. Using our methodology, we quantify the information content of those data types. Our results show that information content depends on the type of signal and background as well as how deep the signal is in the tissue. This type of analysis is meant to guide experimental techniques to be suited for the desired detection task.

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Leung, Chung-Chu, and 梁中柱. "Use of generalized fuzzy operator in digital subtraction radiography." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31245614.

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Marshall, Nicholas W. "Optimisation of digital image intensifier and computed radiography systems." Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246136.

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Gobbi, David G. (David Gregory) Carleton University Dissertation Physics. "A High-pressure gas microstrip detector for digital radiography." Ottawa, 1997.

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Sivard, Seth A. "Digital radiography in the education of radiologic technology students." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1409229904.

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Johnson, Kennita A. "Quantifying computed radiography (CR) and digital radiography (DR) image quality and patient dose for pediatric radiology." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001030.

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Mörner-Svalling, Ann-Catherine. "Digital intraoral radiography determination of technical properties and application evaluations /." Stockholm, Sweden : Departments of Oral Radiology and Oral and Maxillofacial Surgery, Institute of Odontology, Karolinska Institutet, 2002. http://catalog.hathitrust.org/api/volumes/oclc/49899342.html.

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Ariga, Eiji, Shigeki Ito, Shizuhiko Deji, Takuya Saze, and Kunihide Nishizawa. "Development of dosimetry using detectors of diagnostic digital radiography systems." American Association of Physicists in Medicine, 2007. http://hdl.handle.net/2237/8818.

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Doyle, Philip. "Assessment and optimisation of digital radiography systems for clinical use." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/873/.

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Digital imaging has long been available in radiology in the form of computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound. Initially the transition to general radiography was slow and fragmented but in the last 10-15 years in particular, huge investment by the manufacturers, greater and cheaper computing power, inexpensive digital storage and high bandwidth data transfer networks have lead to an enormous increase in the number of digital radiography systems in the UK. There are a number of competing digital radiography (DR) technologies, the most common are computer radiography (CR) systems followed by indirect digital radiography (IDR) systems. To ensure and maintain diagnostic quality and effectiveness in the radiology department appropriate methods are required to evaluate and optimise the performance of DR systems. Current semi-quantitative test object based methods routinely used to examine DR performance suffer known short comings, mainly due to the subjective nature of the test results and difficulty in maintaining a constant decision threshold among observers with time. Objective image quality based measurements of noise power spectra (NPS) and modulation transfer function (MTF) are the ‘gold standard’ for assessing image quality. Advantages these metrics afford are due to their objective nature, the comprehensive noise analysis they permit and in the fact that they have been reported to be relatively more sensitive to changes in detector performance. The advent of DR systems and access to digital image data has opened up new opportunities in applying such measurements to routine quality control and this project initially focuses on obtaining NPS and MTF results for 12 IDR systems in routine clinical use. Appropriate automatic exposure control (AEC) device calibration and a reproducible measurement method are key to optimising X-ray equipment for digital radiography. The uses of various parameters to calibrate AEC devices specifically for DR were explored in the next part of the project and calibration methods recommended. Practical advice on dosemeter selection, measurement technique and phantoms were also given. A model was developed as part of the project to simulate CNR to optimise beam quality for chest radiography with an IDR system. The values were simulated for a chest phantom and adjusted to describe the performance of the system by inputting data on phosphor sensitivity, the signal transfer function (STF), the scatter removal method and the automatic exposure control (AEC) responses. The simulated values showed good agreement with empirical data measured from images of the phantom and so provide validation of the calculation methodology. It was then possible to apply the calculation technique to imaging of tissues to investigate optimisation of exposure parameters. The behaviour of a range of imaging phosphors in terms of energy response and variation in CNR with tube potential and various filtration options were investigated. Optimum exposure factors were presented in terms of kV-mAs regulation curves and the large dose savings achieved using additional metal filters were emphasised. Optimum tube potentials for imaging a simulated lesion in patient equivalent thicknesses of water ranging from 5-40 cm thick for example were: 90-110kVp for CsI (IDR); 80-100kVp for Gd2O2S (screen /film); and 65-85kVp for BaFBrI. Plots of CNR values allowed useful conclusions regarding the expected clinical operation of the various DR phosphors. For example 80-90 kVp was appropriate for maintaining image quality over an entire chest radiograph in CR whereas higher tube potentials of 100-110 kVp were indicated for the CsI IDR system. Better image quality is achievable for pelvic radiographs at lower tube potentials for the majority of detectors however, for gadolinium oxysulphide 70-80 kVp gives the best image quality. The relative phosphor sensitivity and energy response with tube potential were also calculated for a range of DR phosphors. Caesium iodide image receptors were significantly more sensitive than the other systems. The percentage relative sensitivities of the image receptors averaged over the diagnostic kV range were used to provide a method of indicating what the likely clinically operational dose levels would be, for example results suggested 1.8 µGy for CsI (IDR); 2.8 µGy for Gd2O2S (Screen/film); and 3.8 µGy for BaFBrI (CR). The efficiency of scatter reduction methods for DR using a range of grids and air gaps were also reviewed. The performance of various scatter reduction methods: 17/70; 15/80; 8/40 Pb grids and 15 cm and 20 cm air gaps were evaluated in terms of the improvement in CNR they afford, using two different models. The first, simpler model assumed quantum noise only and a photon counting detector. The second model incorporated quantum noise and system noise for a specific CsI detector and assumed the detector was energy integrating. Both models allowed the same general conclusions and suggest improved performance for air gaps over grids for medium to low scatter factors and both models suggest the best choice of grid for digital systems is the 15/80 grid, achieving comparable or better performance than air gaps for high scatter factors. The development, analysis and discussion of AEC calibration, CNR value, phosphor energy response, and scatter reduction methods are then brought together to form a practical step by step recipe that may be followed to optimise digital technology for clinical use. Finally, CNR results suggest the addition of 0.2 mm of copper filtration will have a negligible effect on image quality in DR. A comprehensive study examining the effect of copper filtration on image quality was performed using receiver operator characteristic (ROC) methodology to include observer performance in the analysis. A total of 3,600 observations from 80 radiographs and 3 observers were analysed to provide a confidence interval of 95% in detecting differences in image quality. There was no statistical difference found when 0.2 mm copper filtration was used and the benefit of the dose saving promote it as a valuable optimisation tool.

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Borys, Jennifer. "Higher Voltage Influence on Optimal Caries Diagnosis in Digital Radiography." Thesis, Umeå universitet, Tandläkarutbildning, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-98886.

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It has previously been shown that caries diagnostics is improved when performed on radiographs exposed with a voltage of 60 kV compared to 70 kV. This is because low voltage provides higher subject contrast. The aim of the present study was to investigate whether the tube voltage used when exposing bitewings, influence the possibility to diagnose caries when using a new digital system with CMOS-sensors. Extracted teeth were mounted and bitewings exposed with both 60 and 70 kV and varying exposure times, using a digital system with CMOS-sensors. Observers with different experience in dentistry evaluated the radiographs for caries. CBCT of each single tooth was used as golden standard. There was no significant difference between the results of diagnosing caries between radiographs exposed with 60 kV compared to 70 kV. All radiographs that were exposed to an acceptable level of brightness gave similar result, independent on voltage. In conclusion; there was no significant difference between radiographic caries diagnosis performed with radiographs exposed with 60 compared to 70 kV, given that the exposure time was optimized. This indicates that 70 kV can be used for all intraoral examination if a correct decreased exposure time is used and that lowering to 60 kV is not necessary when intraoral examinations for caries evaluation are performed.

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Toljamo, P. (Päivi). "Dual-energy digital radiography in the assessment of bone characteristics." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526209319.

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Abstract Today, the diagnosis of osteoporosis and assessment of fracture risk is based on estimation of bone mineral density (BMD) determined by dual-energy X-ray absorptiometry (DXA). A lack has been shown in the prediction of individual fracture risk using DXA-based BMD (BMDDXA). Digital radiography (DR) has eased the application of dual-energy techniques for separating bone and soft tissue, but the direct application of dual-energy digital radiography (DEDR) to determine BMD has not been investigated. Additionally, with BMD and bone mass, bone geometry affects strongly the mechanical strength of bone. Geometrical parameters can also be determined from the DR images. This study aimed to investigate the ability of DEDR to determine BMD and whether the combination of DEDR-based BMD and geometry improves the prediction of maximal load. Fracture and osteoporosis diagnoses could thus be done with one examination, i.e. with DEDR, whereas in the current routine both DR imaging and DXA examination are needed for diagnoses. Reindeer femora were imaged by DR with two different energies (79 and 100 kVp). The different geometrical parameters were also determined from the 79 kVp images. The BMD measured by DEDR (BMDDEDR) were calculated using the calculation principle of DXA. The ability of BMDDEDR to predict BMDDXA was investigated. The femora were mechanically tested in an axial loading configuration with the shaft in a vertical position to determine mechanical parameters. The best combination of BMDDEDR and geometrical parameters to predict bone maximal load was explored. BMDDXA was used for comparison. Significant moderate to high linear correlations were observed in all regions of the upper femur (femoral neck, Ward’s triangle, trochanter and inter-trochanter) between BMDDEDR and BMDDXA. BMDDEDR of the femoral neck and BMDDXA of the femoral neck predicted maximal load similarly. The best combination of parameters to predict maximal load was BMDDEDR at Ward’s triangle, femoral shaft diameter (FSD) and femoral shaft axis length (FNAL) (r = 0.79, p < 0.05). The study shows that DEDR is a suitable method to determine BMD in vitro and the combination of BMD and geometry improves the prediction of bone maximal load when compared to BMDDEDR of femoral neck or trochanter only. The thesis also includes unpublished data from a preliminary human study Tiivistelmä Osteoporoosin diagnosointi ja murtumariskin määrittäminen perustuvat kaksienergisellä röntgenabsorptiometrialla (DXA) mitattavaan luun mineraalitiheyden (BMD) arviointiin. DXA:lla määritetyn luun mineraalitiheyden (BMDDXA) on kuitenkin osoitettu olevan puutteellinen murtumariskin yksilöllisessä ennustamisessa. Digitaalinen röntgenkuvaus (DR) on helpottanut sellaisten kaksienergisten tekniikoiden toteuttamista, joissa luu ja pehmytkudos on eroteltu toisistaan. Kaksienergisen digitaalisen röntgenkuvausmenetelmän (DEDR) soveltamista BMD:n määrittämiseen ei ole tutkittu. BMD:n ja luun massan lisäksi on luun geometrialla vahva vaikutus luun mekaaniseen lujuuteen. Geometriset parametrit voidaan määrittää niin ikään digitaalisista röntgenkuvista. Tässä työssä tutkittiin, pystytäänkö DEDR:llä määrittämään BMD sekä parantaako DEDR:llä mitattujen BMD:n ja geometrian yhdistelmä luun maksimikuormituksen ennustetta. Näin ollen murtuma- ja osteoporoosidiagnoosit voitaisiin tehdä yhdellä tutkimuksella (DEDR), kun nykyisin diagnoosit vaativat sekä digitaalisen röntgenkuvauksen että DXA-tutkimuksen. Poron reisiluut kuvattiin digitaalisen röntgenlaitteen kahdella eri kuvausjännitteellä (79 ja 100 kVp). 79 kVp -kuvista määritettiin myös erilaiset geometriaparametrit. BMD laskettiin DEDR-kuvista (BMDDEDR) DXA:n laskentaperiaatetta käyttäen. BMDDEDR:n kyky ennustaa BMDDXA:a tutkittiin. Maksimikuormituksen selvittämiseksi reisiluut testattiin mekaanisesti aksiaalisuunnassa varren ollessa pystysuorassa asennossa. BMDDEDR- ja geometriaparametreista määritettiin paras yhdistelmä maksimikuorman ennustamiseen. BMDDXA-arvoja käytettiin analysoinnissa vertailun vuoksi. BMDDEDR- ja BMDDXA-arvojen välillä havaittiin merkitsevä keskinkertainen tai korkea korrelaatio kaikissa mielenkiintoalueissa (reisiluun kaula, Wardin kolmio, sarvennoisen alue ja reisiluun varren alue). Wardin kolmiosta mitatun BMD:n (WABMDDEDR), reisiluun varren halkaisijan (FSD) ja reisiluun kaulan kautta kulkevan akselin (FNAL) yhdistelmä ennusti parhaiten luun haurautta (r = 0.79, p < 0.05). Tutkimus osoittaa, että DEDR on sopiva menetelmä BMD:n määrittämiseen tutkimusolosuhteissa ja että BMD:n ja geometrian yhdistelmä parantaa maksimikuormituksen ennustetta pelkästään reisiluun kaulasta tai sarvennoisesta mitattuun BMDDEDR:iin verrattuna. Väitöskirja sisältää myös julkaisemattomia tuloksia alustavista ihmistutkimuksista

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Dissertations / Theses on the topic 'Digital radiographic'

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