A conexão do implante com o componente protético é associado a remodelação óssea ao seu redor por servir de nichos para a colonização bacteriana. A proposta deste estudo é verificar se a vedação da conexão com dimetacrilato promove uma perda óssea menor. Foram utilizados 20 implantes ósseos Bone Level® Straumann, indicados para reabilitação protética unitária cimentada. Os pilares protéticos foram instalados nos grupos controle e experimental, adicionando-se o dimetacrilato à interface da conexão protética. Foram realizadas radiografias iniciais no dia da instalação do pilar e outra radiografia após 6 meses. As radiografias foram comparadas e medidas quanto a área de remodelação e perda vertical. A mediana da perda óssea em área foi de -1,16 mm2 e -1,05 mm2 e a média da perda em altura foi de -0.13 mm (±0,05) e -0,05 mm (±0,04) no grupo controle e experimental respectivamente. Os resultados não apresentaram diferença estatística significante em p > 0,05. Apesar de já ser comprovada a eficácia da vedação da interface com o dimetacrilato, o procedimento não foi suficiente para influenciar na remodelação óssea ao redor dos implantes. Entretanto, mais estudos devem ser desenvolvidos a fim de verificar se a vedação ajuda na sobrevivência dos implantes e incidência de peri-implantite. / The implant connection with the prosthetic component is associated with bone loss around the implants to serve as niche for bacterial colonization. The purpose of this study is to verify if sealing the connection with dimethacrylate promotes a lower bone loss. Twenty Straumann ® Bone Level implants were used, indicated for unitary cemented prosthetic rehabilitation. The abutments were installed in the control and experimental groups, adding the dimethacrylate to the prosthetic connection interface. Initial radiographs were obtained right after the pillar installation and another radiograph after 6 months. The radiographs were compared and measured as the area of remodeling and vertical loss. The mean bone loss in area was -1.16 mm2 and -1.05 mm2 and the average height loss was -0.13 mm (± 0.05) -0.05 mm (± 0.04) in the control and experimental group respectively. The results showed no statistically significant difference at p > 0.05. Although a study demonstrate the efficacy of the interface with the sealing dimethacrylate, the procedure was not sufficient to influence the bone remodeling around the implants. However, more studies are needed to verify that the seal helps the survival of implants and incidence of peri-implantitis.

There is a growing interest in understanding recruitment, retention, and turnover of allied health professionals in consideration of employment trends and workforce mobility, an increased need to understand the healthcare delivery system and the dynamic nature of the allied health workforce, especially for rural areas. A survey was sent to allied health administrators across a variety of allied health disciplines from the state of Tennessee hospitals in order to gauge opinions on retention and recruitment strategies. Overall, successful strategies for recruitment and retention of radiography professionals were reported, as well as, differences between urban and rural areas, differences among allied health disciplines, perceptions of strategy effectiveness, and key strategies for rural allied health recruitment.

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.

Thesis (MPH.) -- University of Limpopo, 2012

Orientador: Daniele Cristina Cataneo / Resumo: Objetivo: Comparar características epidemiológicas dos pacientes com diagnóstico de carcinoma broncogênico submetidos a tratamento cirúrgico com aqueles inoperáveis ao diagnóstico, identificar os fatores que levaram ao diagnóstico tardio e propor um novo protocolo de diagnóstico rastreamento. Métodos: estudo observacional retrospectivo, através de coleta de dados de prontuários de pacientes com diagnóstico de carcinoma broncogênico atendidos entre 2005 e 2018. Foram coletados dados clínicos, de exames laboratoriais, exames de imagem e terapêutica instituída. A amostra foi submetida análise descritiva de frequências. Em seguida foi dividida em dois grupos: operado e não operado, que foram comparados utilizando teste do qui quadrado e teste t, considerando significativo p < 0,05. As variáveis foram comparadas com a sobrevida utilizando os testes citados e o método de Kaplan-Meier para obtenção das curvas de sobrevida. Resultados: foram avaliados 230 pacientes com diagnóstico tomográfico ou anátomo-patológico de carcinoma broncogênico, tendo mais de 50% da amostra estadio avançado. Apenas 42 pacientes apresentavam doença operável ao diagnóstico. Nos dois grupos a massa pulmonar ao diagnóstico foi o achado de imagem mais frequente, visível na radiografia simples. No grupo inoperável, houve maior prevalência de sintomas e alterações laboratoriais associadas. A sobrevida foi impactada de forma negativa por alterações laboratoriais, tamanho do tumor e pior pontuação nos scores de pe... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Objective: to compare patients diagnosed with bronchogenic carcinoma who underwent surgical resection and those with inoperable disease at diagnosis, to identify factors leading to late diagnosis and to suggest a new diagnosis and screening protocol. Method: retrospective observational study, through data available in medical records from patients diagnosed with bronchogenic carcinoma between 2005 and 2018. We collected data regarding clinical features, laboratory exams, imaging exams and treatment. Data was analyzed using descriptive statistics and frequency distributions. Patients were also divided into two groups: operable and inoperable, and comparisons between these groups were made using Chi-square test and Student’s t test. We considered the differences significant when p < 0,05. All variables were compared to survival using the same tests and through the Kaplan-Meier Method. Results: we evaluated 230 patients who had tomographic or pathological diagnosis of bronchogenic carcinoma. More than 50% of the patients were in advanced stages of the disease, and only 42 patients had operable disease when diagnosed. In both groups, pulmonary mass was the most frequent alteration at diagnosis, and all were visible in chest radiograph. Among the patients in the inoperable group, symptoms and altered laboratory exams were more frequent. Presence of laboratory alterations, dyspnea, tumor size and worse punctuation in performance scores resulted in lower survival rates. Conclusion: ... (Complete abstract click electronic access below) / Mestre

Introduction: Aseptic loosening is the most common indication for revision surgery of hipimplants. However, sometimes diagnosis from planar radiography is uncertain, makingdecision regarding revision surgery problematic. Implant Movement Analysis (IMA) is anewly introduced method of analysing uncertain aseptic loosening of hip prostheses. It usescomputer tomography with rotational provocation to expose movement of the implantrelatively to the surrounding bone. Aim: To evaluate the role of IMA as a complementary method to planar radiography indiagnosing aseptic loosening of total hip artroplasty (THA) at Lindesberg Hospital. 1) HasIMA improved diagnosing of uncertain cases of aseptic loosening? 2) Has IMA reduced thenumber of unnecessary THA revision surgeries? Methods: Retrospective cohort study analysing 43 cases of uncertain aseptic looseningexamined with IMA at Lindesberg Hospital. Paired results from planar radiography and IMAwere statistically compared with McNemar’s test, IMA held as the reference. Additional datawas also collected (i.e. age and symptoms). Results: Planar radiography had 70 % sensitivity and 65 % specificity compared to certainresults from IMA. IMA provided diagnoses in 84 % of the cases and changed the diagnosisfor 33 % compared to planar radiography. Eight cases got their diagnosis changed from looseto not loose. Conclusions: IMA has improved diagnosing cases of uncertain aseptic loosening and cantherefore be seen as a good complementary method to planar radiography in these cases.However, as it is a new method further evaluation is needed.

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.

This dissertation presents a novel method for removing scattering effects from Nuclear Materials Identification System (NMIS) imaging. The NMIS uses fast neutron radiography to generate images of the internal structure of objects non-intrusively. If the correct attenuation through the object is measured, the positions and macroscopic cross-sections of features inside the object can be determined. The cross sections can then be used to identify the materials and a 3D map of the interior of the object can be reconstructed. Unfortunately, the measured attenuation values are always too low because scattered neutrons contribute to the unattenuated neutron signal. Previous efforts to remove the scatter from NMIS imaging have focused on minimizing the fraction of scattered neutrons which are misidentified as directly transmitted by electronically collimating and time tagging the source neutrons. The parameterized scatter removal algorithm (PSRA) approaches the problem from an entirely new direction by using Monte Carlo simulations to estimate the point scatter functions (PScFs) produced by neutrons scattering in the object. PScFs have been used to remove scattering successfully in other applications, but only with simple 2D detector models. This work represents the first time PScFs have ever been applied to an imaging detector geometry as complicated as the NMIS. By fitting the PScFs using a Gaussian function, they can be parameterized and the proper scatter for a given problem can be removed without the need for rerunning the simulations each time. In order to model the PScFs, an entirely new method for simulating NMIS measurements was developed for this work. The development of the new models and the codes required to simulate them are presented in detail. The PSRA was used on several simulated and experimental measurements and chi-squared goodness of fit tests were used to compare the corrected values to the ideal values that would be expected with no scattering. Using the PSRA resulted in an improvement of the chi-squared test by a factor of 60 or more when applied to simple homogeneous objects.

Aims: The overall aim of this thesis was to explore and describe radiographers‟ professional competence based on patients‟ and radiographers‟ experiences and to develop a context-specific instrument to assess the level and frequency of use of radiographers‟ professional competence. Methods: The design was inductive and deductive. Both qualitative and quantitative methods were used. The data collection methods comprised interviews (Studies I-II) and questionnaires (Studies III-IV). The subjects were patients in study I and radiographers in studies II-IV. In study I, 17 patients were interviewed about their experiences of the encounter during radiographic examinations and treatment. The interviews were analysed using qualitative content analysis. In study II, 14 radiographers were interviewed to identify radiographers‟ areas of competence. The critical incident technique was chosen to analyse the interviews. Studies III and IV were based on a national cross-sectional survey of 406 randomly selected radiographers. Study III consisted of two phases; designing the Radiographer Competence Scale (RCS) and evaluation of its psychometric properties. A 42-item questionnaire was developed and validated by a pilot test (n=16) resulting in the addition of 12 items. Thus the final RCS comprised a 54-item questionnaire, which after psychometric tests was reduced to 28 items. In study IV, the 28-item questionnaire served as data. The level of competencies was rated on a 10-point scale, while their use was rated on a six-point scale. Results: In study I, the female patients‟ comprehensive understanding was expressed as feelings of vulnerability. The encounters were described as empowering, empathetic, mechanical and neglectful, depending on the radiographers‟ skills and attitudes. Study II revealed two main areas of professional competence, direct patient-related and indirect patient-related. The first focused on competencies in the care provided in close proximity to the patient and the second on competencies used in the activities of the surrounding environment. Each of the two main areas was divided into four categories and 31 sub-categories that either facilitated or hindered good nursing care. In study III the analysis condensed the 54-item questionnaire in two steps, firstly by removing 12 items and secondly a further 14 items, resulting in the final 28-item RCS questionnaire. Several factor analyses were performed and a two factor-solution emerged, labelled; “Nurse initiated care” and “Technical and radiographic processes”. The psychometric tests had good construct validity and homogeneity. The result of study IV demonstrated that most competencies in the RCS received high ratings both in terms of level and frequency of use. Competencies e.g. „Adequately informing the patient‟, „Adapting the examination to the patient‟s prerequisites and needs‟ and „Producing accurate and correct images‟ were rated the highest while „Identifying and encountering the patient in a state of shock‟ and „Participating in quality improvement regarding patient safety and care‟ received the lowest ratings. The total score of each of the two dimensions had a low but significant correlation with age and years in present position. The competence level correlated with age and years in present position in both dimensions but not with the use of competencies in the “Nurse initiated care” dimension. Conclusion: This thesis has shown that professional competence is important in the encounter between patient and radiographer. It has also demonstrated that radiographers‟ self-rated professional competence is based on nursing, technological and radiographic knowledge. From a radiographer‟s perspective, „Nurse initiated care‟ and „Technical and Radiographic processes‟ are two core dimensions of Radiographer Competence Scale. The 28-item questionnaire regarding level and frequency of use of competence is feasible to use to measure radiographers‟ professional competence.

Simulation is an important tool when training is hazardous, time consuming, or expensive. Simulation can also be used to enhance reality by adding features normally not available in the real world. The aim with this work has been to develop and evaluate methods that could improve learning in oral radiology utilising a radiation-free simulator environment. Virtual reality software for radiographic examinations was developed. The virtual environment consisted of a model of a patient, an x-ray machine, and a film. Simulated radiographic images of the patient model could be rendered as perspective projections based on the relative position between the individual models. The software was incorporated in an oral radiology simulator with a training program for interpretation of spatial relations in radiographs. Projection geometry was validated by comparing length dimensions in simulated radiographs with the corresponding theoretically calculated distances. The results showed that projection error in the simulated images never exceeded 0.5 mm. Dental students participated in studies on skill in interpreting spatial information in radiographs utilising parallax. Conventional and simulator based training methods were used. Training lasted for 90 minutes. Skill in interpreting spatial information was assessed with a proficiency test before training, immediately after training, and eight months after training. Visual-spatial ability was assessed with mental rotations test, version A (MRT-A). Regression analysis revealed a significant (P&lt;0.01) association between visual-spatial ability and proficiency test results after training. At simulator training, proficiency test results immediately after training were significantly higher than before training (P&lt;0.01). Among students with low MTR-A scores, improvement after simulator training was higher than after conventional training. Eight months after simulator training proficiency test results were lower than immediately after training. The test results were, however, still higher than before training. In conclusion, the simulation software produces simulated radiographs of high geometric accuracy. Acquisition of skill to interpret spatial relations in radiographs is facilitated for individuals with high visual-spatial ability. Simulator training improves acquisition of interpretative skill and is especially beneficial for individuals with low visual-spatial ability. The results indicate that radiology simulation can be an effective training method.