In 2010, the Royal College of Radiologists introduced workplace-based assessments to the postgraduate training pathway for clinical radiologists in the UK. Whilst the system served the purpose of contributing to high-stakes annual judgements about radiology trainees’ progression into subsequent years of training, it was primarily intended to be formative. This study was prompted by an interest in whether the new system fulfilled this formative role. Data collection and analysis spanned the first three years of the new system and followed a multi-methods approach. Descriptive statistical analysis was used to explore important parameters such as the timing and number of assessments undertaken by trainees and assessors. Using the literature and an iterative analysis of a large sample of trainee data, a coding framework for categories of feedback quality enabled assessors’ written comments to be explored using deductive and inductive qualitative analysis, with inferential statistical analysis of coded assessor feedback statements. For example, Ragin’s (1987, 2000, 2008) qualitative comparative analysis, QCA, was used to explore whether the assessments met necessary and/or sufficient conditions for high quality feedback. Pairs of assessor-trainee feedback comments were also analysed to establish whether any dialogic feedback interactions occurred. The study presents evidence that despite its intentions, the new system is generally failing to meet its primary, formative aim. As a consequence, the influence of negative washback on assessment practice was reflected in a number of findings. For example, there was evidence of trainees taking an instrumental approach to the assessments, undertaking only the prescribed minimum of assessments or completing assessments in the later stages of placements. Combined with evidence of retrospective assessment, i.e. after completion of the placements, the observed patterns of assessment over the three years are consistent with a box-ticking approach. This study explores the contextual policy and practice dimensions underpinning these and related findings and discusses the implications and recommendations for future arrangements.

This book provides an introductory overview of a wide range of commonly encountered medical imaging tests including radiation- based techniques such as plain film radiography, computed tomography and nuclear medicine, and non-ionising imaging techniques such as medical ultrasound and magnetic resonance imaging... Chapter 7 Balancing risk and benefit in diagnostic imaging.

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This thesis explores learning in clinical practice in the cases of CT, MRI and PACS in UK hospitals. It asks the questions of how and why certain evolutionary features of technology condition learning and change in medical contexts. Using an evolutionary perspective of cognitive and social aspects of technological change, this thesis explores the relationships between technology and organisational learning processes of intuition, interpretation, integration and institutionalisation. Technological regimes are manifested in routines, skills and artefacts, and dynamically evolve with knowledge accumulation processes at the individual, group and organisational levels. Technological change increases the uncertainty and complexity of organisational learning, making organisational outcomes partially unpredictable. Systemic and emergent properties of medical devices such as CT and MRI make learning context-specific and experimental. Negotiation processes between different social groups shape the role and function of an artefact in an organisational context. Technological systems connect artefacts to other parts of society, mediating values, velocity and directionality of change. Practice communities affect how organisations deal with this complexity and learn. These views are used to explore the accumulation of knowledge in clinical practices in CT, MRI and PACS. This thesis develops contextualised theory using a case-study approach to gather novel empirical data from over 40 interviews with clinical, technical, managerial and administrative staff in five NHS hospitals. It uses clinical practice (such as processes, procedures, tasks, rules, interpretations and routines) as a unit of analysis and CT, MRI and PACS technology areas as cases. Results are generalised to evolutionary aspects of technological learning and change provided by the framework, using processes for qualitative analysis such as ordering and coding. When analysed using an evolutionary perspective of technology, the findings in this thesis suggest that learning in clinical practice is diverse, cumulative and incremental, and shaped by complex processes of mediation, by issues such as disease complexity, values, external rules and choice restrictions from different regimes, and by interdisciplinary problem-solving in operational routines.

Submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2017. / Radiographs are the most commonly used modalities for the purpose of diagnosing skeletal disorders. Radiographs are important for chiropractors to exclude any contra-indications prior to spinal manipulative therapy. If contra-indications are found treatment is modified to what best suits each patient. There is a gap in the literature regarding chiropractors reading the same set of radiographs and agreeing on findings. Objectives The study investigated inter- and intra-examiner reliability of lumbar spine radiograph analysis by chiropractors and its impact on clinical management. Methods Inter- and intra-examiner examination of radiographs occurred in two rounds separated by two weeks. Six chiropractors read the same 30 radiographs and clinical history was only available in the second round. Results Inter-observer agreement for categorisation for Round One was 96.78% and Round Two 89.49%. Inter-observer agreement in management was 96.45% in round one and 96.00% in Round two. Agreement between chiropractors had no statistically significant difference. Identification average improved from 0.09 to 0.89 kappa. Overall specificity was relatively high and sensitivity was relatively low. Conclusion Reliability/Agreement between chiropractors was strong in both rounds. Categorising of the diagnosis improved from poor to substantial from Round One to Round Two. Case history improved the accuracy of interpreting the radiographs although this change was not statistically significant. / M

The goal of this study was to improve dosimetry for pelvic, lung, head and neck, and other cancers sites with aspherical planning target volumes (PTV) using a new algorithm for collimator optimization for intensity modulated radiation therapy (IMRT) that minimizes the x-jaw gap (CAX) and the area of the jaws (CAA) for each treatment field. A retroactive study on the effects of collimator optimization of 20 patients was performed by comparing metric results for new collimator optimization techniques in Eclipse version 11.0. Keeping all other parameters equal, multiple plans are created using four collimator techniques: CA0, all fields have collimators set to 0°, CAE, using the Eclipse collimator optimization, CAA, minimizing the area of the jaws around the PTV, and CAX, minimizing the x-jaw gap. The minimum area and the minimum x-jaw angles are found by evaluating each field beam’s eye view of the PTV with ImageJ and finding the desired parameters with a custom script. The evaluation of the plans included the monitor units (MU), the maximum dose of the plan, the maximum dose to organs at risk (OAR), the conformity index (CI) and the number of fields that are calculated to split. Compared to the CA0 plans, the monitor units decreased on average by 6% for the CAX method with a p-value of 0.01 from an ANOVA test. The average maximum dose remained within 1.1% difference between all four methods with the lowest given by CAX. The maximum dose to the most at risk organ was best spared by the CAA method, which decreased by 0.62% compared to the CA0. Minimizing the x-jaws significantly reduced the number of split fields from 61 to 37. In every metric tested the CAX optimization produced comparable or superior results compared to the other three techniques. For aspherical PTVs, CAX on average reduced the number of split fields, lowered the maximum dose, minimized the dose to the surrounding OAR, and decreased the monitor units. This is achieved while maintaining the same control of the PTV. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Empirical methods of beam angle optimization (BAO) are tested against the BAO that is currently employed in Eclipse treatment planning software. Creating an improved BAO can decrease the amount of time a dosimetrist spends on making a treatment plan, improve the treatment quality and enhance the tools an inexperienced dosimetrist can use to develop planning techniques. Using empirical data created by experienced dosimetrists from 69 patients treated for lung cancer, the most frequently used gantry angles were applied to four different regions in each lung to gather an optimal set of fields that could be used to treat future lung cancer patients. This method, given the moniker FAU BAO, is compared in 7 plans created with the Eclipse BAO choosing 5 fields and 9 fields. The results show that the conformality index improved by 30% or 3% when using the 5 and 9 fields. The conformation number was better by 12% from the 5 fields and 9% from the 9 fields. The organs at risk (OAR) were overall more protected to produce fewer nonstochastic effects from the radiation treatment with the FAU BAO. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Intensity modulated radiation therapy (IMRT) is a cancer treatment method in which the intensities of the radiation beams are modulated; therefore these beams have non-uniform radiation intensities. The overall result is the delivery of the prescribed dose in the target volume. The dose distribution is conformal to the shape of the target and minimizes the dose to the nearby critical organs. An inverse planning algorithm is used to obtain those non-uniform beam intensities. In inverse treatment planning, the treatment plan is achieved by using an optimization process. The optimized plan results to a high-quality dose distribution in the planning target volume (PTV), which receives the prescribed dose while the dose that is received by the organs at risk (OARs) is reduced. Accordingly, an objective function has to be defined for the PTV, while some constraints have to be considered to handle the dose limitations for the OARs. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Orientador: Sérgio Santos Muhlen / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-18T02:41:28Z (GMT). No. of bitstreams: 1 Loureiro_ClarissaFernandaCorreiaLima_M.pdf: 2106734 bytes, checksum: 61a0c8655393190312aacd0f345e5f92 (MD5) Previous issue date: 2011 / Resumo: Estabelecer os efeitos biológicos e níveis seguros de exposição à radiação ionizante é um objetivo a ser alcançado até os dias de hoje. Mamografia é um exame importante na detecção precoce de tumores na mama, mas desde que os genes BRCA1 e BRCA2 foram identificados como a causa principal de câncer de mama hereditário, existe uma preocupação crescente em relação à exposição às radiações ionizantes de pacientes portadoras de mutações nestes genes. A exposição poderia induzir um aumento nas mutações nos genes BRCA e outros supressores e promover o desenvolvimento do tumor nestas pacientes. Neste trabalho é proposto um estudo experimental in vitro inicial com o objetivo de determinar o nível de radiação que desencadeia mutações detectáveis nos genes BRCA, e quantificar um nível mais seguro de radiação nas mamografias de pacientes portadoras de mutações em alelo desses genes. Células de mama provenientes de uma paciente foram cultivadas e irradiadas com diferentes doses de raios X, gerados por um mamógrafo comercial. Os resultados mostram que radiações ionizantes promovem alterações mensuráveis nas células de mama cultivadas / Abstract: Establishing the biological effects and the safe level of exposure to ionizing radiation remains, so far, an objective to be reached. Mammography is an important exam in the early detection of breast tumors, but since the genes BRCA1 and BRCA2 were identified as a main cause of hereditary breast cancer, there is growing concern of exposing patients carrying those mutations to ionizing radiation. It could increase mutations in these genes and other suppressors, and promote the development of tumor in those patients. In this study we propose an in vitro initial experiment aiming to determine the radiation trigger level for detectable mutations in genes BRCA, and thus a safer level of radiation due to mammography for patients carrying a mutated allele of the genes BRCA1 or BRCA2. Breast cells from one patient were cultivated and irradiated with different doses of X-rays generated by commercial mammography equipment. The results have shown that exposition to ionizing radiation promotes measurable alterations in breast cell grown / Mestrado / Engenharia Biomedica / Mestre em Engenharia Elétrica