Dissertations / Theses on the topic 'Radiographic film'

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.

Doctor of Philosophy<br>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.

Thesis (M.S.D.)--Indiana University School of Dentistry, 2009.<br>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).

The purpose of this study was to compare three direct digital sensors (Kodak 6100, Schick CDR, and Dexis PerfectSize), a phosphor plate system (OpTime), and F-speed film to standard D-speed film in the detection of artificial bone lesions prepared in mandible bone sections. Multiple artificial bone lesions were prepared at varying depths in the cortical bone. Specimens were imaged with six different radiographic systems. Radiographs were randomly presented to nine different observers. A logistic regression analysis indicated that the ability of the different radiographic systems to detect the bone lesions was significantly different at the mean percentage of cortical bone remaining. The Kodak filtered, Schick filtered, OpTime unfiltered, Schick unfiltered, and Dexis filtered images were significantly better at lesion detection compared to D-speed film. Also, all filtered digital images were significantly better at lesion detection than D-speed film.

Thesis (M.S.D.)--Indiana University School of Dentistry, 2009.<br>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).

This thesis considers the effects of Picture Archive and Communications Systems (PACS), on both patient radiation doses and patient management. PACS is a relatively new technology which acquires, transmits, and stores radiological images digitally. This thesis investigates the doses which are required to produce radiographic images which are acceptable to radiologists and referring clinicians, and compares these doses with those required for the film/screen systems which they are replacing. A review of the literature shows that despite claims of dose reductions, very little good evidence exists about dose changes with the introduction of PACS. A comparison of images of test objects indicates that the images are comparable under limited conditions, that PACS has a much wider latitude than film (>250 mAs), and that contrast detail improves with increase in exposure. Two original observational studies are described in which PACS and film doses are compared for examinations of two groups of adult patients. The results indicate that the doses for PACS equate to those used with a 300 speed film/screen system thus necessitating dose increases of around 30% for the majority of adult patients in the UK. The issue of whether the number of images which are repeated, with additional patient doses, due to unsatisfactory images (rejected images), or unavailability of the images when clinically required (lost images), is addressed and indicates that PACS may allow a dose saving of 1.1 % and 1.4% respectively. The overall result of these studies indicates that the widespread introduction of PACS is likely to increase population doses. Two original studies which consider patients within the Accident and Emergency department are described. These studies aim to produce evidence to justify the introduction of the new technology, despite higher radiation doses, by identifying improvements in patient management which might improve patient outcomes. The results of these studies provide little evidence of such benefits to patients. This thesis concludes that the use of current PAC systems produces an increase in the radiation dose to the adult population in the UK, without demonstrable improvements in patient management.

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

Purpose: The purpose of this study was to assess the radiographic changes in periapical status and analysis of healing determined using periapical radiographs (PA) versus cone beam computed tomography (CBCT) pre-operatively and at 3-64 months following endodontic treatment. Methods: Pre/post treatment radiograph and CBCT scans of patients who had NSRCT, NSReTx, or SRCT from July 2011-December 2018 at VCU Graduate Endodontic clinic were included in this study. Volumetric and linear measurements of periapical lesions on initial and recall PA and CBCT images were performed using three calibrated examiners. Changes and differences in the estimated area from PA to CBCT were compared using the Wilcoxon signed-rank test. McNemar’s chi-squared test was used to determine agreement in the proportion of lesions that were absent (0x0) between the PA and corresponding view of CBCT. This data was used to calculate the sensitivity, specificity, positive predictive value (PPV), and negative predicative value (NPV). Results: A total of 51 patients with a median healing time of 13 months were included in the analysis. Significant healing was observed on both PA and CBCT images (p-value Conclusion: Assessment using CBCT revealed a lower healing rate for all treatment categories compared with periapical radiographs. CBCT was more likely to detect the presence of a PARL, whereas a periapical radiograph would be less sensitive to detection of a PARL. Significant healing cannot be detected at an earlier point in time with PA radiographs or CBCT.

The production of good quality radiographs is a complex process, given the high level of image quality required (Sniureviciute & Adliene, 2005: 260). Exposure of patients to x-rays, a factor in the production of quality radiographs also entails a risk of radiation injury. In 2006, computerized radiography (CR) was introduced at The Nairobi Hospital to try and reduce the film reject rate, decrease repeats, reduce financial costs of consumables like x-ray films and processing chemicals. However, to date, no formal film reject analysis has been conducted at The Nairobi Hospital. Four years after the incorporation of CR, there is apparently, still a significant number of film rejects, implying operational costs may still be high. The cause of film rejects and overall reject cost is not known. This has led to the research question: “Has the film reject rate in the A & E x-ray unit at The Nairobi Hospital reduced following incorporation of CR?” A quantitative, retrospective, descriptive study involving a reject film analysis of rejected radiographs in the Accident and Emergency (A&E) x-ray unit in the Nairobi Hospital, Kenya was conducted. The researcher collected data for a period of 6 months between 2/12/07 and 28/05/08 using a purpose-designed data collection form. All rejected x-ray films during the study period were included. Capture and analysis of the collected data was completed by the researcher using SPSS 10 and EPINFO computer packages. Permission to conduct the study was obtained from The Nairobi Hospital Education Committee and due consideration to patient and radiographer confidentiality was maintained throughout the study. A total of 851(2.5 percent) x-ray films were collected during the study period. Four hundred and fourteen (2.6 percent) radiographs and 437 (2.5 percent) radiographs were rejected prior to and after the incorporation of CR respectively. Chest radiographs were the most frequently rejected accounting for 277(66.9 percent) and 123 (28.1 percent) prior to and after the incorporation of CR respectively. The most frequently rejected film size was 35x35cm prior to the incorporation of CR (61.6 percent) and 26x35cm film size after the incorporation of CR (91.3 percent). The most frequent cause of film rejects was radiographer causes both prior to and after the incorporation of CR accounting for 496 (58.3 percent). The film reject rate did not significantly reduce after the incorporation of CR, suggesting that there are other factors which contribute to reject rate, other than CR. The study also shows that higher film consumption does not necessarily lead to high reject rates. The percentage value on annual rejects did not change after the incorporation of CR and a demonstrated increase in the annual cost of purchasing x-ray films was attributed to an increase in annual consumption after the incorporation of CR, and also to the higher cost of digital x-ray films. Despite some identified limitations to this study, some recommendations, which included conduction of regular reject analyses and regular continuing professional development with respect to radiographic technique amongst others, were suggested.

Nos travaux ont pour objet l'amelioration des performances des films en imagerie x. Nous les utilisons en radiographie eclair de puissance pour des applications de detonique. Les performances en sensibilite et en resolution spatiale de notre cellule radiographique (ecran metallique/ecran luminescent/film/ecran luminescent/ecran metallique), dependent de deux parametres. Le premier est le rendement de conversion des ecrans luminescents. Ceux-ci, stimules par des rayons x, emettent de la lumiere dans le domaine spectral de plus haute sensibilite des films. Pour un ecran luminescent ce rendement est fonction de l'energie des photons incidents. Il depend egalement de la nature des ecrans metalliques participant a l'equilibre electronique. A partir de simulations monte carlo, nous avons considere que la sensibilite de l'ecran etait representee par le depot total d'energie et que sa resolution l'etait par la repartition spatiale de ce depot. Ces resultats nous ont permis de determiner sans ambiguite une cassette specifique pour la radiographie eclair de puissance constituee d'un empilement de cellules elementaires. Le second parametre est la reponse du film. Pour mieux distinguer l'information du bruit, nous avons ameliore le traitement chimique des films en laboratoire. Afin de quantifier les ameliorations, nous avons defini un critere de minimum detectable que nous avons aussi etudie en fonction du vieillissement de l'image latente. Nous obtenons un gain en sensibilite d'un facteur deux aussi bien par le developpement pousse que par la methode d'hypersensibilisation par forming gaz. Le developpement pousse est deja implante de facon operationnelle

The thesis looks at various aspects of the modulation transfer function (MTF) and Wiener spectrum (WS) measurements for screen-film systems aiming at robust and simple methods for their routine measurement in a hospital setting. To measure the MTF of the film-screen systems, the square wave response function method was used. To normalise the MTF at a lower spatial frequency, a lead step and an object were incorporated into the measurement. Work on fitting the MTF data was carried out by considering two MTF models. To check if the current MTF calculation makes a low estimate, calculation using more terms in the Coltmann equation was performed. The value of the edge spread function method to measure the MTF was examined. The MTF of the microdensitometer was measured, and the correction factor for the screen-film. MTF based on this was calculated. MTF measurements of several screen-film combinations in use at the Aberdeen Royal Infirmary were made. The method used for the measurement of the WS of the screen-film was the fast Fourier transform digital method. A proper normalisation was chosen and implemented in the calculation. Low pass filtering, low frequency filtering, and windowing of the density fluctuation data were examined using sinusoidal and real noise data. The square shape of the scanning aperture of the microdensitomer was taken into account in the determination of WS. Slit length was synthesised and incorporated into the WS calculation. WS measurements of several screen-film combinations were made. A short receiver operating characteristic (ROC) study of two screen-film systems, recently introduced into Aberdeen Royal Infirmary, was undertaken to study the relationship between the physical measures of image quality that had been developed and the subjective measure based on the area under the ROC curve.

Made available in DSpace on 2014-10-09T12:46:31Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T13:56:22Z (GMT). No. of bitstreams: 1 07977.pdf: 2200288 bytes, checksum: 75fcd64975e2719bf0f41d38ec387c77 (MD5)<br>Dissertacao (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Made available in DSpace on 2015-05-14T12:56:05Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1129487 bytes, checksum: 9b4bcacf33a745b3f606911583f777bb (MD5) Previous issue date: 2009-12-10<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>The use of intraoral radiographs is quite common in daily practice of dentistry and the radiographic film has been the most used means of capture, disposal and storage of radiographic images. However, X-ray emission can produce deleterious biological effects. One of the easiest ways to reduce the radiation needed to produce radiographs is the use of more sensitive films. The choice of these films is essential, since the radiographic quality is not compromised. The films have different behaviors in the changing of the type of processing, concentration, temperature and state of degradation of processing solutions. This study aimed to evaluate the F-speed film DFL Contrast® FV-58 and compare it with the Kodak Insight® E/F speed film. The parameters studied were the sensitometric properties, the relative contrast and base plus fog density. These parameters were calculated from values of optical density and the sensitometric properties used also measures of radiation dose. In order to observe the behavior of the films in fresh and degraded solutions, a model of degradation was created that lasted four weeks. The quality parameters were measured at five different times and the results showed that the Contrast® film has sensitivity, contrast and base plus fog density significantly higher, whereas the values of latitude are minor. The relative contrast showed no significant difference between the types of film. The degradation time of processing solutions were not significant in the parameters studied. It was concluded that the claims of the manufacturer of the film Contrast® is correct and confirm the characteristics of film, the highest sensitivity and contrast that the Insight® film<br>A utilização de radiografias intrabucais é bastante comum na prática diária da Odontologia e o filme radiográfico tem sido o meio mais usado de captura, disposição e armazenamento das imagens radiográficas. Entretanto, as radiações X podem produzir efeitos biológicos deletérios. Uma das formas mais simples de reduzir a radiação que chega ao paciente é o uso de filmes mais sensíveis. A escolha desses filmes é essencial, desde que a qualidade radiográfica não seja prejudicada. Os filmes apresentam comportamentos diferentes frente às variações do tipo de processamento, concentração, temperatura e ao estado de degradação de soluções processadoras. O presente estudo teve como objetivo avaliar o filme DFL Contrast® FV-58 de sensibilidade F e compará-lo com o filme Kodak Insight®, de sensibilidade E/F. Os parâmetros estudados foram as propriedades sensitométricas, o contraste relativo e a densidade base e velamento. Esses parâmetros foram calculados a partir de valores de densidade óptica e o cálculo das propriedades sensitométricas também se utilizou de medidas de dose de radiação. Com a finalidade de observar o comportamento dos filmes em soluções frescas e degradadas, foi criado um modelo de degradação que durou quatro semanas. Os parâmetros de qualidade foram medidos em cinco tempos distintos e os resultados mostraram que o filme Contrast® possui valores de sensibilidade, contraste e densidade base e velamento significativamente maiores, enquanto os valores de latitude são menores. O contraste relativo não mostrou diferença significativa entre os tipos de filme. O tempo de degradação das soluções de processamento não mostrou significância nos parâmetros estudados. Concluiu-se que as alegações do fabricante do filme Contrast® estão corretas e confirmam as características desse filme, de maior sensibilidade e contraste que o filme Insight®.

Objetivos: Comparar as densidades base e velamento de quatro filmes radiográficos: Ultra-speed; D; E e Insight (Eastman Kodak Company, Rochester, E.U.A.) utilizando-se os processamentos automáticos roller e nonroller. Métodos:Tabela comparativa foi construída para os quatro filmes utilizando-se duas condições de processamento e a mesma solução processadora (Kodak Readymatic). Todos os filmes foram processados automaticamente utilizando-se o equipamento AT2000 (Air Techniques, Hicksville, E.U.A.) com velocidade normal e Periomat (Dürr Dental, Bietigheim-Bissingen, Alemanha). Análise comparativa foi realizada para avaliar a densidade base e velamento para cada filme e processadora. Resultados: As maiores densidades base e velamento, foram alcançadas nos três filmes (Ultra-speed, E e Insight) utilizando-se o equipamento AT2000 com velocidade normal. A maior DBV para o filme D foi observada utilizando-se a processadora Periomat. Conclusões: O filme Insight deve ser processado utilizando-se o sistema roller (AT2000) com velocidade normal para alcançar densidade base e velamento ideal. A utilização da Periomat causa redução da DBV para os filmes Ultra-speed, E e Insight. O filme D é o único que apresenta aumento da DBV neste sistema nonroller.<br>Objectives: To compare base-plus-fog densities of four radiographic films: Ultra-speed, D-Speed; E-Speed and Insight (Eastman Kodak Company, Rochester, USA) using roller and nonroller machines. Methods: Comparative table was constructed for four films using two different processing conditions and the same processing solution (Kodak Readymatic). All films were automatically processed using AT2000 machine (Air Techniques, Hicksville, USA) in normal speed and Periomat machine (Dürr Dental, Bietigheim-Bissingen, Germany). Comparative analysis had been performed to evaluate the base-plus-fog density to each film. Results: Greater base-plus- fog densities were reached in three films (Ultra-speed, E and Insight) using the equipment AT2000 in normal speed. The greater BPFD to D film had been observed to the Periomat machine. Conclusions: The Insight film has to be processed using the roller machine (AT2000) in normal speed to achieve optimal base-plus-fog density. The use of Periomat had caused reduction in BPFD to Ulra-speed, E and Insight films. The D film is the unique that presents increasing in BPFD in this nonroller system.

Orientador: Francisco Haiter Neto<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-04T03:47:02Z (GMT). No. of bitstreams: 1 Pontual_AndreadosAnjos_M.pdf: 23672659 bytes, checksum: 557d0af196a3b37022ea269439130873 (MD5) Previous issue date: 2005<br>Resumo: O objetivo nesse trabalho foi avaliar a eficácia dos sistemas digitais Digora®, com as placas de fósforo branca e azul, e DenOptix®, assim como do filme radiográfico Insight®, na detecção de cáries proximais incipientes em esmalte, comparando os resultados obtidos na avaliação radiográfica com a mensuração histológica de extensão destas lesões. Em seguida, foi verificado se o aumento da extensão da lesão cariosa acarretaria maior detecção radiográfica das mesmas. Foram obtidas imagens interproximais de 20 phantoms, constituídos de dentes humanos, que foram avaliadas por 17 cirurgiões-dentistas quanto à presença e extensão de lesões cariosas por meio da atribuição de escores. Posteriormente, os dentes foram seccionados e analisados microscopicamente para obtenção do padrão ouro. As faces que apresentaram cárie em esmalte, 64 (42,1%), foram avaliadas quanto a sua extensão na camada de esmalte. Utilizou-se o teste de Friedman (p<0,05) para verificar se existiu diferença estatisticamente significativa entre a moda das avaliações radiográficas das modalidades de imagem e entre estas e o padrão ouro. Foi aplicado o teste não-paramétrico de comparações múltiplas (p<0,05), para revelar quais métodos em questão apresentaram diferença estatisticamente significativa. Os resultados não mostraram diferenças estatisticamente significativas entre os sistemas digitais e o filme radiográfico no diagnóstico de cáries proximais em esmalte, entretanto, todas as modalidades de imagem foram diferentes do padrão ouro. Na comparação das avaliações radiográficas com a extensão da lesão de cárie em relação à camada de esmalte, observou-se que aumento da extensão da lesão cariosa não acarretou maior detecção radiográfica<br>Abstract: The aim of this study was to evaluate the efficacy of the digital systems Digora®, with white and blue phosphor plates, and DenOptix®, as well as of the radiographic film Insight®, for detection of incipient proximal caries in enamel, comparing the results achieved in the radiographic evaluation with histological measurement of the extension of these lesions. Thereafter, it was observed whether the increase in the extension of the carious lesion would increase their radiographic detection. Interproximal images were achieved from 20 phantoms, composed of human teeth, which were evaluated by 17 dental professionals as to the presence and extension of carious lesions by assigning scores. Then, the teeth were sectioned and microscopically analyzed for achievement of the gold standard. The surfaces presenting enamel caries, 64 (42.1%), were evaluated as to their extension in the enamel layer. The Friedman test was used (p<0.05) to check if there was a statistically significant difference between the mode of the radiographic evaluations of each type of image and between them and the gold standard. The nonparametric test for multiple comparisons was applied (p<0.05) to reveal which methods analyzed presented a statistically significant difference. The results did not demonstrated statistically significant differences between the digital systems and the radiographic film for diagnosis of proximal caries in enamel; however, all types of image were different from the gold standard. Comparison between the radiographic evaluations and the extension of the carious lesion in relation to the enamel layer revealed that the increase in extension of the carious lesion did not increase the radiographic detection<br>Mestrado<br>Radiologia Odontologica<br>Mestre em Radiologia Odontológica

Made available in DSpace on 2014-10-09T12:53:57Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:09:29Z (GMT). No. of bitstreams: 0<br>Tese (Doutoramento)<br>IPEN/T<br>Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

L’obiettivo di questo lavoro è quello di contribuire allo sviluppo di un’epistemolo-gia dell’imaging medico, intendendo con questo termine sia le immagini utilizzate a fini diagnostici, sia le tecnologie che le producono. La mia tesi principale è che le tecnologie di imaging medico non si limitano a produrre immagini più o meno accurate degli organi interni e di alcuni processi fisiologici, ma piuttosto trasformano il corpo in un oggetto scientifico, operando un cambiamento profondo della sua visibilità. Gli strumenti di imaging mutano il corpo in un oggetto visivo che può essere osservato in condizioni sperimentali. A differenza del corpo reale, tale oggetto può essere archiviato, consultato, condiviso, misurato e manipolato in varie maniere. Questa tesi di fondo è accompagnata da altre due: (1) Le immagini diagnostiche, come tutte le immagini scientifiche, sono veri e propri strumenti cognitivi, strumenti epistemici integrati in un quadro teorico-pratico specifico; (2) Un’immagine che rivela l’interno dell’organismo ha significato e valore diagnostico solo nell’ambito di una specifica concettualizzazione del corpo e della malattia, di conseguenza uno studio sull’epistemologia dell’imaging medico non si potrà limitare a esaminare le immagini diagnostiche in quanto immagini, ma dovrà analizzarle anche nella loro veste di strumenti di diagnosi medica. Per questo motivo nel primo capitolo della dissertazione traccio le linee generali delle condizioni di possibilità storiche e concettuali della radiografia -- la prima tecnologia di imaging medico -- inventata nel 1895. Lo scopo è quello di comprendere quali teorie e pratiche mediche dovessero essere vigenti alla fine del XIX secolo, affinché immagini che parevano ombre del corpo interno potessero essere considerate strumenti diagnostici. La spiegazione da me proposta è che la rilevanza diagnostica della radiografia si fonda sulla concettualizzazione di corpo, malattia e diagnosi resa operativa dall’anatomia clinica già alla fine del XVIII secolo. Seguendo e supportando questa linea di ragionamento mostro che lo stetoscopio, inventato nel 1816, può essere considerato il predecessore materiale e intellettuale dell’imaging medico perché introdusse una primitiva forma di mediazione sensoriale nel campo della diagnostica e permise al medico di esplorare dall’esterno le profondità del corpo del paziente, estraendone segni di malattia. Lo stetoscopio è solo il primo di una vasta famiglia di strumenti inventati nel XIX secolo per visualizzare diversi aspetti della morfologia interna e della fisiologia del vivente. Sebbene ciascuno di questi strumenti rispondesse a specifiche necessità diagnostiche e ponesse specifici problemi epistemologici, si possono identificare alcune caratteristiche comuni: tutti avevano come obbiettivo quello di sostituire le sensazioni soggettive dei pazienti e dei medici con indici oggettivi di salute e malattia; tutti creavano registri visivi dell’interno del corpo umano che potevano essere archiviati, recuperati e condivisi da diversi medici; tutti richiedevano la creazione di un linguaggio specializzato, condiviso da una comunità medico-scientifica; tutti creavano una progressiva separazione tra il corpo del paziente e il corpo del medico. È in questo complesso scenario di pratiche, oggetti, raffigurazioni e idee che la radiografia fece la sua comparsa e acquisì la sua funzione diagnostica. Nel secondo capitolo prendo in esame la nascita della fotografia, al fine di comprendere in che modo la prima tecnologia di produzione meccanica di immagini influenzò la medicina. I principali riferimenti teorici di questo capitolo sono dati dalla semiotica di Charles Sanders Peirce, in particolare la sua classificazione dei segni in indici, icone e simboli, e dalla riflessione di Walter Benjamin sulla serie fotografica (produzione e riproduzione meccanica di un’immagine e del corpo in essa rappresentato), sull’intrinseco potenziale analitico e di dissezione della fotografia (il fotografo come chirurgo), e sull’inconscio ottico (fotografia come protesi che arricchisce e trasforma l’esperienza sensibile). Basandomi su questi autori e esaminando i lavori dei primi medici-fotografi nell’ambito della psichiatria, dermatologia, fisiologia e neurologia, mostro che le serie fotografiche raccolte in riviste mediche, manuali di studio e archivi ospedalieri produssero uno sguardo clinico in senso foucauldiano. Sostengo, inoltre, che la serie fotografica faceva parte di un più ampio apparato sperimentale che includeva il paziente, la macchina fotografica e l’osservatore il cui scopo era trasformare il corpo e la malattia in oggetti visivi che potessero essere sottoposti ad analisi scientifica. Nel terzo capitolo discuto il problema del referente invisibile, ossia analizzo i processi attraverso cui le immagini fotografiche di oggetti invisibili vengono dotate di significato. Probabilmente questo è il problema fondamentale di qualunque tipo di imaging scientifico. Quando il referente di una fotografia è invisibile, la modalità iconica di significazione non può essere messa in atto, perché nell’immagine prodotta dallo strumento (sia esso meccanico o elettronico) non possiamo riconoscere nessuna similitudine con l’oggetto rappresentato. Di fatto, potremmo dire che in questi casi l’immagine non assomiglia a nulla. Come sappiamo, dunque, se l’oggetto che vediamo nella fotografia – per esempio una cellula o una lesione tubercolare – è davvero là, e possiede davvero l’aspetto mostrato dall’immagine? Sulla scorta dell’analisi teorica sviluppata nel capitolo precedente, difendo l’idea che la visualizzazione dell’invisibile richieda una peculiare combinazione delle modalità di significazione indicale, iconica e simbolica. La mia argomentazione è costruita in opposizione al concetto di oggettività meccanica proposto da Lorraine Daston e Peter Galison. In particolare, dimostro che l’idea di oggettività meccanica come soppressione moralizzante del soggetto proposta dai due storici è una caricatura delle idee e pratiche sviluppate dagli scienziati del XIX secolo per risolvere il problema della visualizzazione dell’invisibile. La mia argomentazione si articola in tre momenti, corrispondenti all’analisi del problema dell’oggettività e della significazione delle immagini in tre diversi ambiti: microfotografia, cronofotografia e radiografia. Nel quarto capitolo affronto il problema del valore cognitivo delle immagini, sostenendo che le immagini sono strumenti epistemici (nel senso forte, non metaforico della parola strumento) e che rappresentazione e osservazione non sono mai atti puramente automatici, perché richiedono sempre una componente creativa. Come nel capitolo precedente, parte del mio discorso è una refutazione della posizione di Daston e Galison, in particolare per quanto riguarda le loro affermazioni sulla natura passiva di certe rappresentazioni visive. Secondo Daston e Galison, infatti, fino allo sviluppo delle tecnologie digitali, le immagini scientifiche erano mere ri-presentazioni [re-presentations] del mondo, miranti a copiare la natura. Con la comparsa del digitale, invece, si è passati a un’epoca in cui le immagini sono presentazioni [presentations], perché attraverso di esse l’osservatore può visualizzare l’oggetto in mutevoli forme, manipolandolo virtualmente. La mia critica a questa posizione è basata su argomenti storici e teorici. Sul piano storico mostro che i primi tentativi di creare immagini mediche manipolabili risalgono almeno al XVI secolo. Sul piano teorico, ricorrendo alla letteratura prodotta in campi così diversi come la teoria dell’arte e le neuroscienze, dimostro che la nozione di ricezione passiva di un’immagine è insostenibile, perché le immagini coinvolgono sempre l’osservatore in un atto corporeo di percezione che sollecita non solo sensazioni visive, ma anche sensazioni tattili e reazioni motorie. Inoltre, sostengo che l’enfasi posta da Daston e Galison sul nanoimaging come l’unica tecnologia che permette di manipolare l’oggetto durante la fase di produzione di un’immagine è fuorviante. Infatti, anche nei casi in cui non raggiungono le vette di sofisticazione tecnologica proprie delle nano-immagini, le immagini scientifiche sono sempre il risultato di una manipolazione dell’oggetto naturale rappresentato. Un’immagine scientifica non può essere una mera copia della natura, perché è sempre parte di una praxis sperimentale il cui obiettivo è comprendere un fenomeno naturale, non solo riprodurlo. Per corroborare questa idea analizzo alcune pratiche concrete di significazione di immagini scientifiche, prendendo in esame documenti scritti (analisi semiotica di un articolo di radiologia) e pratiche materiali (etnografia di laboratorio riguardante l’interpretazione di immagini di elettroforesi in biologia molecolare e descrizione di un caso di significazione di immagini di microscopia elettronica). Questa analisi permette di fare tre osservazioni: (1) Il processo di significazione delle immagini scientifiche è un processo distribuito; (2) Le immagini scientifiche possono essere considerate strumenti di ricerca, nel senso che scienziati e medici le manipolano in varie forme al fine di esplorare aspetti diversi del loro oggetto di studio; (3) Le immagini scientifiche vanno comprese come fenomeni artificiali controllati prodotti allo scopo di ridefinire la visibilità degli oggetti naturali. Per approfondire meglio quest’ultima idea, nel capitolo finale introduco il concetto di fenomenotecnica sviluppato da Gaston Bachelard. La nozione di fenomenotecnica non può essere applicata direttamente all’imaging medico, ma alcuni degli elementi che caratterizzano il concetto bachelardiano offrono spunti importanti per pensare l’imaging medico. Il primo di questi elementi è l’idea che per studiare un fenomeno naturale, lo scienziato deve innanzitutto trasformarlo in un oggetto scientifico. Il secondo elemento, strettamente legato al primo, è che l’esperienza scientifica è necessariamente mediata, e tale mediazione ha un carattere intellettuale e materiale. Questo significa che la costruzione di strumenti e lo sviluppo di tecnologie non sono un prodotto della scienza, ma piuttosto un elemento interno al processo scientifico. La tecnologia è integrata nella scienza, perché la nostra apprensione? scientifica del mondo è necessariamente mediata da strumenti. Gli strumenti, a loro volta, sono materializzazioni di un vasto corpo di conoscenze e pratiche scientifiche (nel caso dell’imaging digitale tale sapere ha un carattere eminentemente matematico). Scienza e tecnologia, dunque, si costituiscono reciprocamente. A partire da queste considerazioni propongo un descrizione dell’imaging medico in termini di fenomenotecnica, utilizzando tale concetto come parola chiave attorno alla quale riorganizzare le idee discusse in precedenza. In primo luogo ricorro al concetto di fenomenotecnica per spiegare come le immagini diagnostiche mediano l’esperienza sensoriale e intellettuale del medico. Successivamente descrivo le immagini diagnostiche in termini di fenomeni artificiali (riconfigurazione visiva di segnali non visivi) che funzionano come simulazioni del corpo del paziente e che materializzano ambiti della conoscenza differenti (dalla medicina alla fisica, passando per l’ingegneria). Infine, mostro che la significazione corretta ed efficace di un’immagine diagnostica richiede una fenomenotecnica dell’osservatore. Per riconoscere i segni di malattia in un’immagine dell’interno del corpo è necessario padroneggiare le regole implicite ed esplicite che permettono di dare senso al nuovo dominio sensoriale prodotto dalla tecnologia. Ciò implica un abbandono dei modi spontanei di percezione-significazione e il passaggio attraverso un processo educativo che modula le capacità percettive. L’osservatore specializzato è un osservatore che ha preso parte a un processo di formazione che trasforma profondamente la visione naturale, inserendo l’atto del guardare all’interno di una vasta rete epistemica che include conoscenze teoriche e pratiche concrete.<br>The objective of this dissertation is to contribute to the development of an epistemology of medical imaging. My central thesis is that medical imaging does not merely produce more or less accurate pictures of the inner organs, it rather transforms the living body into a scientific object by changing its very visibility. The imaging apparatus turns the body into a visual object that can be observed under experimental conditions: unlike the real body, it can be filed, retrieved, shared, measured and manipulated in several ways. This main thesis is accompanied by two others: first, diagnostic images, as all scientific images, are actual cognitive instruments, epistemic objects inscribed within theoretical contexts and experimental practices. Second, an image of the inner body has diagnostic meaning and value only in the scope of a specific conceptualization of the body and its ailments. Accordingly, if we are to develop an epistemology of medical imaging, we cannot limit our analysis to diagnostic images qua images, we also have to understand them qua diagnostic instruments. This is why at in the first chapter of the dissertation I take into examination the historical and conceptual conditions of possibility of radiography -- the first medical imaging technology, invented in 1895. My aim is to understand what medical theories and practices had to be at work in the nineteenth century, for those shadow-images produced by the X-ray apparatus to be perceived and employed as diagnostic devices. I argue that the diagnostic relevance of radiography is rooted in the conceptualization of body, disease and diagnosis put forward by clinical anatomy already at the end of the eighteenth century. I also defend the idea that the stethoscope, developed in 1816, was the material and intellectual predecessor of medical imaging, because it introduced a primitive form of mediated perception in medical diagnosis, and allowed the clinician to explore from the outside the inner body of the living patient, extracting signs of illness. The stethoscope was only the first of a vast array of instruments invented in the nineteenth century to visualize different aspects of the inner morphology and physiology of the living body. Each of these instruments fulfilled specific diagnostic aims and posed distinct epistemological problems, but all of them shared some commonalities: they were meant to replace the subjective sensations of patients and doctors with objective indices of health and disease; they created visual records of the inner body that could be filed, retrieved and shared among physicians; they required the development of a specialized language agreed upon by a community of experts; they created a progressive physical separation between the body of the patient and the body of the physician. It was in this complex scenario of medical practices, objects, images and ideas that radiography appeared and progressively acquired its diagnostic function. In the second chapter I take into account the early developments of medical photography in order to understand how the first technology for the production of mechanical images entered and influenced the domain of medicine. The main theoretical references in this chapter are Charles Sanders Peirce's semiotics, in particular, his classification of signs in indices, icons and symbols, and Walter Benjamin's reflections on the photographic series (mechanical production and reproduction of an image and of the body it represents), on the intrinsic analytic and dissecting potential of photography (the photographer as a surgeon), and on the optical unconscious (photography as a prosthesis that enriches and transforms our sensorial experience). Drawing on these authors, and analyzing the works of early physicians-photographers in psychiatry, dermatology, neurology and physiology, I show that the photographic series collected in medical journals, manuals and hospital archives, produced a clinical gaze in the Foucauldian sense. I also argue that the photographic series was part of a larger experimental apparatus, which encompassed the patient, the camera and the observer, and whose aim was to turn the body and disease into a visual object available for scientific analysis. In the third chapter I discuss the problem of the invisible referent, that is, I analyze the processes whereby photographs that reveal invisible phenomena are endowed with meaning. This is likely to be the fundamental problem of all scientific imaging. When the referent of a picture is invisible, the iconic mode of signification fails, because in this case the image produced by the mechanical or electronic apparatus does not look like anything we already know, it resembles nothing. So, how do we know that the object we see in the photograph -- e.g., a cell or a tubercular lesion -- is really there and does really look like that? Drawing on the theoretical analysis developed in the previous chapter, I maintain that the visualization of the invisible entails a peculiar combination of the indexical, iconic and symbolic modes of signification. My reasoning opposes Lorraine Daston and Peter Galison's idea of mechanical objectivity, and demonstrates that their notion of mechanical objectivity as the moralizing suppression of subjectivity is a caricature of the actual ideas and practices developed by the scientists of the nineteenth century to deal with the problem of visualizing the invisible. The argument is articulated in three moments, corresponding to the analysis of the problem of objectivity and image signification in microphotography, chronophotography, and radiography. In the fourth chapter I argue that images are cognitive tools and that representation and observation are never an act of automated repetition, they always entail a creative component. As in the previous chapter, part of my discourse is built in contrast with Daston and Galison, challenging their claims concerning the passive nature of representation. For these authors, until the development of digital technologies for image manipulation, scientific images were mere re-presentations of the world, focused on copying nature. Computer images, on the contrary, are presentations, because the observer can virtually manipulate them so that they show the object in ever changing ways. I criticize this classification of scientific images with historical and theoretical arguments. From the historical point of view, I show that at least since the sixteenth century there have been attempts to create images that can be actually manipulated by the observer. From the theoretical perspective, I draw on a variety of literature spanning from art theory to neuroscience, to demonstrate that the very notion of a passive representation is unsustainable, because images always engage the observer in an embodied act of perception, which elicits not only visual, but also tactile sensations and motor reactions. Moreover, I argue that Daston and Galison's emphasis on nanoimaging as the only technology that allows manipulating the object of study during the process of image production is misleading. In fact, even when they do not reach the peaks of technological sophistication that characterizes nanoimages, scientific images are the result of some manipulation of the natural object they represent. A scientific image cannot be a passive copy of nature, because it is part of an experimental praxis, whose goal is to understand natural phenomena, not just to reproduce them. To corroborate this idea I explore actual scientific practices of image signification, taking into account written documents (semiotic analysis of a radiology article) and material practices (laboratory ethnography describing the interpretation of electrophoresis images in a molecular biology laboratory, and description of an example of signification of electron microscopy pictures). From this analysis three remarks can be put forward: (1) the process of signification of scientific images has a distributed character, because it can involve different persons, objects and activities; (2) scientific images can be considered experimental tools, in the sense that scientists and physicians handle them in several forms in order to explore different aspects of their object of study; (3) scientific images are to be understood as controlled, artificial phenomena produced with the aim of redefining the visibility of natural objects. In order to clarify this latter idea, in the final chapter I introduce Gaston Bachelard's concept of phenomenotechnique. Although the idea of phenomenotechnique cannot be directly applied to medical imaging, there are two characterizing elements of this concept that provide important insights for conceptualizing medical imaging. The first is the idea that in order to study a natural phenomenon, scientists must previously transform it into a scientific object. The second, closely related to the former, is that scientific experience is by necessity mediated, and such mediation has both an intellectual and material character. This means that the development of instruments and new technologies is not a second-order product of science, it is part and parcel of the scientific process. Technology is embedded into science, because our scientific grasping of the world is necessarily mediated by instruments; scientific instruments, in turn, are materializations of a vast body of scientific knowledge and practices (in the case of digital imaging this knowledge has an eminently mathematical character). Thus, science and technology are reciprocally constituted. On these grounds I propose a description of medical imaging in terms of phenomenotechnique, using this concept as a key-word around which to reorganize the ideas previously discussed. Firstly, I resort to the concept of phenomenotechnique to gain insights into how diagnostic images mediate the physician's sensory and intellectual experience. Second, I give an account of diagnostic images as artificial phenomena (visual reconfigurations of non-visual signals) that work as simulations of the patient's body, and that reify different domains of knowledge (from medicine to physics and engineering). Finally, I argue that the proper and efficient signification of a diagnostic image requires a phenomenotechnique of the observer. To recognize the signs of disease in an image of the inner body, one has to master the explicit and implicit rules necessary to make sense of the novel sensory domain produced by the technological apparatus. This implies abandoning spontaneous modes of perception and signification to engage in a process of educated perception. The expert viewer goes through a formal and informal training that deeply transforms natural vision, by placing the act of watching within a wide epistemic network that encompasses both theoretical and practical knowledge.

No<br>Purpose: The immobilisation and restraint of children to facilitate radiographic examination is a controversial issue that has been relatively ignored by radiography research. The aim of this study was to begin to fill this gap by providing a description of restraint used in a limited number of clinical sites in order to highlight any perceived need for training, policies or guidelines in the use of child immobilisation and restraint. Methods: A cross-sectional survey design using a postal questionnaire was adopted. One hundred and sixty-seven questionnaires were distributed to radiographers employed within six hospital Trusts. Results: A response rate of 83.2% (n=139/167) was achieved. Ninety-three percent (93.5%, n=130/139) of respondents indicated that restraining techniques were used although only 19.2% (n=25/130) had received specific training in safe restraining techniques and 7.9% (n=11/139) in distraction techniques as an alternative to restraint. A need for further guidance and support for clinical staff was evident with 73.3% (n=74/101) of respondents identifying a need for specific guidelines and 84.6% (n=110/130) indicating that further training opportunities were required. Conclusions: The use of restraint in paediatric plain film radiography is an apparently widespread practice and support for clinical radiographers through the development of training opportunities and practice guidelines are seen as essential in order to promote high quality paediatric radiography practices.

Indiana University-Purdue University Indianapolis (IUPUI)<br>Accurate determination of working length during endodontic therapy is critical in achieving a predictable and successful outcome. Working length is determined by the use of electronic apex locators, tactile perception, knowledge of average tooth lengths and dental radiography. Due to the increasing use of digital radiography in clinical practice, a comparison with conventional film in working length determination is justified. The purpose of this study is to determine if there is a difference between Schick digital radiography and Kodak Ultra-speed film in the accurate determination of working lengths when vertical angulation of the object is variable. Twelve teeth with #15 K-flex files at varying known lengths from the anatomical apex were mounted in a resin-plaster mix to simulate bone density. A mounting jig for the standardization of projection geometries allowed for exact changes in vertical angulation as it related to the object (tooth) and the film/sensor. Each tooth was imaged using Schick CDR and Kodak Ultra-speed film at varying angles with a consistent source-film distance and exposure time. Four dental professionals examined the images and films independently and measured the distance from the tip of the file to radiographic apex and recorded their results. The error in working length was calculated as the observed value minus the known working length for each tooth type. A mixed-effects, full-factorial analysis of variance (ANOVA) model was used to model the error in working length. Included in the ANOVA model were fixed effects for type of image, vertical angulation, and the interaction of angle and film type. Tooth type and examiner were included in the model as random effects assuming a compound symmetry covariance structure. The repeatability of each examiner, for each film type, was assessed by estimating the intra-class correlation coefficient (ICC). The ICC was determined when 12 randomly selected images and radiographs were reevaluated 10 days after initial measurements. The repeatability of each examiner for Schick CDR was good with ICCs ranging from 0.67 to 1.0. Repeatability for the conventional film was poor with ICCs varying from -0.29 to 0.55. We found the error in the working length was not significantly different between film types (p = 0.402). After adjusting for angle, we found that error in the working length from the digital image was only 0.02 mm greater (95-percent CI: -0.03, 0.06) than the conventional film. Furthermore, there was not a significant difference among the angles (p = 0.246) nor in the interaction of image type with angle (p = 0.149). Based on the results of our study, we conclude that there is not a statistically significant difference in determining working length between Schick CDR and Kodak Ektaspeed film when vertical angulation is modified.

Indiana University-Purdue University Indianapolis (IUPUI)<br>Accurate determination of working length during endodontic therapy is a crucial step in achieving a predictable outcome. This is determined by the use of electronic apex locators, tactile perception, and knowledge of average tooth lengths and/or dental radiography whether digital or conventional is utilized. It is the aim of this study to determine if there is a difference between Schick digital radiography and Kodak Insight conventional film in accurately determining working lengths when modifying exposure time and source-film/sensor distance. Twelve teeth with size 15 K-flex files at varying known lengths from the anatomical apex were mounted in a resin-plaster mix to simulate bone density. Each tooth was radiographed while varying the source-film/sensor distance and exposure 122 time. Four dental professionals examined the images and films independently. Ten images and 10 films were selected at random and re-examined to determine each examiner?s repeatability. The error in working length was calculated as the observed value minus the known working length for each tooth type. A mixed-effects, full-factorial analysis of variance (ANOVA) model was used to model the error in working length. Included in the ANOVA model were fixed effects for type of image, distance, exposure time, and all two-way and three-way interactions. The repeatability of each examiner for each film type was assessed by estimating the intra-class correlation coefficient (ICC). The repeatability of each examiner on digital film was good with ICCs ranging from 0.67 to 1.0. Repeatability on the conventional film was poor with ICCs varying from -0.29 to 0.55.We found there was an overall difference between the conventional and digital films (p < 0.001). After adjusting for the effects of distance and exposure time, the error in the working length from the digital image was 0.1 mm shorter (95% CI: 0.06, 0.14) than the error in the working length from the film image. There was no difference among distances (p = 0.999) nor exposure time (p = 0.158) for film or images. Based on the results of our study we conclude that although there is a statistically significant difference, there is no clinically significant difference between digital radiography and conventional film when exposure time and source-film/sensor distance are adjusted.

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

Thesis (M.S.)--University of Louisville, 1996.<br>School of Dentistry, Department of Biological and Biophysical Sciences. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The objectives of this paper are to raise awareness of the methodological standards that can affect the quality of radiographer plain-film reading performance studies and to determine the frequency with which these standards are fulfilled. Multiple search methods identified 30 such studies from between 1971 and the end of June 1999. The percentage of studies that fulfilled criteria for the 10 methodological standards were as follows. (1) Performance of a sample size calculation, 3%; (2) definition of a normal and abnormal report, 97%; (3) description of the sequence of events through which films passed before reporting, 94%; (4) analysis of individual groups of observers within a combination of groups, 50% (5) appropriate choice of reference standard, 80%; (6) appropriate choice of arbiter, 57%; (7) appropriate use of a control, 22%; (8) analysis of pertinent clinical subgroups, e.g. body areas, patient type, 44%; (9) availability of data for re-calculation, 59%; and (10) presentation of indeterminate results, 69%. These findings indicate variation in the application of the methodological standards to studies of radiographer's film reading performance. Careful consideration of these standards is an essential component of study quality and hence the validity of the evidence base used to underpin radiographic reporting policy.

Purpose To raise awareness of the frequency of bias that can affect the quality of radiographer plain film reading performance studies. Methods Studies that assessed radiographer(s) plain film reading performance were located by searching electronic databases and grey literature, hand-searching journals, personal communication and scanning reference lists. Thirty studies were judged eligible from all data sources. Results A one-way analysis of variance (ANOVA) demonstrates no statistically significant difference (P=0.25) in the mean proportion of biases present from diagnostic accuracy (0.37), performance (0.42) and outcome (0.44) study designs. Pearson¿s correlation coefficient showed no statistically significant linear association between the proportion of biases present for the three different study designs and the year that the study was performed. The frequency of biases in film and observer selection and application of the reference standard was quite low. In contrast, many biases were present concerning independence of film reporting and comparison of reports for concordance. Conclusions The findings indicate variation in the presence of bias in radiographer plain film reading performance studies. The careful consideration of bias is an essential component of study quality and hence the validity of the evidence-base used to underpin radiographic reporting policy.

碩士<br>國立陽明大學<br>生物醫學影像暨放射科學系暨研究所<br>100<br>Purpose: Breast cancer screening has been proven effective in Western countries. Taiwan National Health Bureau started to offer free screening mammography for women aged between 50 and 69 since July 2004. This study aims to compare the efficacy between different modalities of screening mammography. Material and Methods: Between July 2004 and December 2010, a total of 23513 eligible women underwent screening mammography in our hospital. 6804 of these received screen-film mammography, 1610 received computed-radiography mammography, and 15099 received digital mammography. The carcinoma-in-situ detection rate, early cancer detection rate, and the overall cancer detection rate of each modality were calculated. Chi-square test was used to determine the statistical significance of performance differences between these modalities. Results: The callback rate of screen-film mammography (SFM) was 12.23%, cancer detection rate was 5.29%, DCIS detection rate was 1.76%. The callback rate of computed radiography (CR) was 12.67%, cancer detection rate was 6.21% and DCIS detection rate was 1.24%. Full-field digital mammography (FFDM) has the highest callback rate of 9.21%, but also the highest rate of cancer detection rate and DCIS detection rate of 9.21% and 3.58% respectively. FFDM has better cancer detection rate and DCIS detection rate compared to SFM and CR, it is only statistically significant when compared to SFM. Although FFDM has better cancer and DCIS detection rates, it is also associated with higher callback rate. Conclusions: Full-field digital mammography has obvious performance advantages over screen-film and computed radiography mammography, this is important especially in Asian populations where dense breasts are more prevalent. Taiwanese breast cancer incidence is gradually increasing and becoming comparable to that of Western countries, and when combined with dense breasts of Asian women and Taiwan’s unique medicolegal ecosystem, results in relatively high callback rate.

Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2012.<br>Background: Attempts to determine the association between the radiographic and clinical findings of knee pathology have produced conflicting results. It is also not yet known how knee radiographs influence the conservative management of patients with knee pain. Objectives: 1. To determine the association between the clinical and radiographic diagnoses of knee pain. 2. To record the consultation at which a radiograph of the knee was requested by the student or clinician and the reasons thereof. 3. To record the suspected clinical diagnoses and management of the patients prior to referral for radiographs of the knee. 4. To determine the number of incidental radiographic findings in the selected radiographs. 5. To determine any change in the clinical diagnoses and management following radiographic reporting of the selected radiographs. Method: Radiographic and clinical data from 1 January 1997 to 31 December 2010 were retrospectively collected from knee radiographs and corresponding patient files from the archives of the Chiropractic Day Clinic (CDC). Statistical analysis included the use of percentages, mean, standard deviation, range and frequency counts for the descriptive objectives. Diagnoses were categorized into specific groups and to construct two-by-two tables of absence or presence of radiographic vs. clinical diagnosis for each specific diagnosis to determine the association indicator variables were used. Results: The overall agreement between the clinical and radiographic diagnoses was 85.5%. For degenerative joint disease there was a 97.8% agreement while in Osgood Schlatter’s disease the agreement was 100%, and in chondromalacia patella the agreement was 50%. However, there was no agreement between the clinical and radiographic diagnoses for each of the other specific conditions. Degenerative changes were the most common radiographic findings. The iv majority of the knee radiographs were requested at the initial consultation and as the length of treatment increased, the frequency of radiograph requests decreased. The most common reasons for referral for radiographs were to identify degenerative changes (47.5%) and to assess for unspecified pathology (37.4%). Of the 146 patients in this study, 125 patients did not have a change in diagnosis after radiographs were obtained which means that 85.6% of the diagnoses remained the same after radiographic examination. There was a wide range of treatment modalities utilized in the management of patients with knee pain, including soft tissue therapy, electrotherapeutic modalities and manual therapy (manipulation and mobilization). The use of manual therapy increased from 67.8% prior to radiographs being taken to 82.9% after radiographs were obtained. Conclusion: Knee radiographs were over-utilized at the CDC and the findings on radiography did not have much influence on the diagnosis and the management of the patient presenting with knee pain. The majority of the clinical diagnoses were degenerative causes of knee pain.

yes<br>Objective: To update knowledge on individual radiographer contribution to plain-film reporting workloads; to assess whether there is scope to further increase radiographer reporting capacity within this area. Methods: Reporting radiographers were invited to complete an online survey. Invitations were posted to every acute National Health Service trust in the UK whilst snowball sampling was employed via a network of colleagues, ex-colleagues and acquaintances. Information was sought regarding the demographics, geographical location and anatomical and referral scope of practice. Results: A total of 259 responses were received. 15.1% and 7.7% of respondents are qualified to report chest and abdomen radiographs, respectively. The mean time spent reporting per week is 14.5 h (range 1–37.5). 23.6% of radiographers report only referrals from emergency departments whilst 50.6% of radiographers have limitations on their practice. Conclusion: The scope of practice of reporting radiographers has increased since previous studies; however, radiographer reporting of chest and abdomen radiographs has failed to progress in line with demand. There remain opportunities to increase radiographer capacity to assist the management of reporting backlogs. Advances in knowledge: This study is the first to examine demographic factors of reporting radiographers across the UK and is one of the largest in-depth studies of UK reporting radiographers, at individual level, to date.

The relaxation of restrictions on the type of professions that can report films has resulted in radiographers and other healthcare professionals becoming increasingly involved in image interpretation in areas such as mammography, ultrasound and plain-film radiography. Little attention, however, has been given to sample size determinations concerning film-reading performance characteristics such as sensitivity, specificity and accuracy. Illustrated with hypothetical examples, this paper begins by considering standard errors and confidence intervals for performance characteristics and then discusses methods for determining sample size for studies of film-reading performance. Used appropriately, these approaches should result in studies that produce estimates of film-reading performance with adequate precision and enable investigators to optimize the sample size in their studies for the question they seek to answer.

Teeth and oral structures are considered valuable alternatives to DNA analysis and fingerprints for personal identification. Even if their reliability has been recognized, they’ve not been widely or at all tested with new technologies. This project had the aim to study the superimposability of dental and oral structures in radiographic examinations and 3D scans and stability of some of them, like palatal rugae, in patients undergoing to dental procedures and cadavers. The survey has been performed on the virtual and plastic reconstruction of the oral cavities developed from data collected from an innovative intraoral scanner and from orthopantomographs (in all patients and cadavers- if available -) and from full-mouth periapical films (in periodontal patients and cadavers only). In all the patients oral cavity scans started at the beginning of the therapeutic procedures and after one year. In cadavers oral cavity scans have been recorded on the first and the seventh or tenth day from the time of death, allowing a complete survey on how long the palatal rugae features and other oral structures remain stable after corruption of the body sets in their intraoral scans have been then superimposed on radiographs. Morphometric data collected from all the virtual and plastic reconstructions and radiographs, have been listed in an electronic paper. The statistical analysis estimated the differences in shape and length of palatal rugae and dental and other intraoral features in the groups. The results confirm the reliability and the superimposability of 2D radiographs with the reconstructions derived from 3D scans as tools for personal identification, allowing to develop a new protocol for personal identification overcomes the so traditional and so invasive oral autopsy.