Radiographic technique modification and evidence-based practice: A qualitative study

Introduction: Evidence-based practice in radiography is an emerging practice, due to a lack of evidence. Beyond the diagnostic requirements of the examination, imaging technique decisions are guided by the radiographer's tertiary education and clinical experience. Imaging technique decisions should include all aspects of evidence-based practice: research-based evidence, patient circumstances and clinical experience. Previous research suggests radiographers do to not fully engage with the latter, which may jeopardise progress in the field and lead to outdated practices and suboptimal outcomes for patients. This study aimed to examine the motivators and influences involved in radiographers' decision-making when modifying imaging acquisition techniques. Methods: An exploratory descriptive, inductive qualitative interview-based design was used with a convenience sample of radiographers from three public hospital sites in Queensland. Twelve one-on-one semi-structured interviews were performed via video conference, the data were analysed through thematic analysis. Results: Five themes emerged from the data: advancement of technology; experience rather than evidence; radiology's influence on radiographic practice; information sources; and image quality. The pursuit of image quality was the key motivator and criterion that influenced radiographers' choices in imaging technique modification. Interviewees did not engage routinely with research-based evidence, preferring to rely on empirical observations and professional experience. Conclusion: The exclusion of research-based evidence can lead to outdated and ineffective clinical decisions. Further work is needed to promote more research in the field of radiography and increase the willingness and capacity of radiographers to follow the principles of evidence-based practice

Stoichiometric control of the density of states in PbS colloidal quantum dot solids

Colloidal quantum dots, and nanostructured semiconductors in general, carry the promise of overcoming the limitations of classical materials in chemical and physical properties and in processability. However, sufficient control of electronic properties, such as carrier concentration and carrier mobility, has not been achieved until now, limiting their application. In bulk semiconductors, modifications of electronic properties are obtained by alloying or doping, an approach that is not viable for structures in which the surface is dominant. The electronic properties of PbS colloidal quantum dot films are fine-tuned by adjusting their stoichiometry, using the large surface area of the nanoscale building blocks. We achieve an improvement ofmore than two orders ofmagnitude in the holemobility, from below 10(-3) to above 0.1 cm(2)/N.s, by substituting the iodide ligands with sulfide while keeping the electron mobility stable (similar to 1 cm(2)/V.s). This approach is not possible in bulk semiconductors, and the developed method will likely contribute to the improvement of solar cell efficiencies through better carrier extraction and to the realization of complex (opto) electronic devices

ODS steel as structral material for high temperature nuclear reactors

Oxide dispersed strengthened (ODS) ferritic-martensitic steels are investigated as possible structural material for the future generation of High Temperature Gas Cooled Nuclear Reactors. The Ni based austenitic ODS superalloys are not considered, because of the Ni presence, which is unfavorable under neutron irradiation. ODS-steels are considered to replace other high temperature materials for tubing or structural parts. Interestingly, ODS is also considered as material being used in future fusion applications. The oxide particles serve for interfacial pinning of moving dislocations. Therefore the creep resistance is improved. In case of the usage of these materials in reactor, the behavior under irradiation must be further clarified. In this paper the effects induced by He implantation are investigated. The induced swelling is measured and the mechanical behavior of the irradiated surface is investigated. These first tests are performed at room temperature, where a clear swelling and hardening could be observed.Окисно дисперговані зміцнені (ОДЗ) феритно-мартенситні сталі досліджуються як можливі конструкційні матеріали для нового покоління високотемпературних ядерних реакторів з газовим охолодженням. Аустенітні ОДЗ-сплави на основі никелю не вивчаються завдяки никелю, присутність якого під дією опромінення небажана. ОДЗ-сталі разглядаються як можливі кандидати на заміну інших високотемпературних матеріалів для вигoтовлення трубопроводів або інших конструкційних вузлів. Цікаво, що ОДЗ-матеріали розглядаються також з точки зору їх можливого використання для майбутнього застосування в термоядерних пристроях. Окисні частки служать як міжфазні пастки для закріплення дислокацій, що рухаються. У разі використання ціх материалів в реакторі їх поведінка під опроміненням повинна вивчатись більш ретельно. В роботі досліджуються ефекти, зумовлені проникненням Не. Вимірюється зумовлене розпухання та механічні характеристики опроміненої поверхні. Ці перші дослідження були виконані при кімнатній температурі, коли можно чітко спостерігати розпухання та зміцнення.Окисно диспергированные упрочненные (ОДУ) ферритно-мартенситные стали изучались как возможные конструкционные материалы для нового поколения высокотемпературных ядерных реакторов с газовым охлаждением. Аустенитные ОДУ-суперсплавы на базе никеля не рассматривались из-за присутствия никеля, который нежелателен при нейтронном облучении. ОДУ-стали рассматривались как возможные заменители других высокотемпературных материалов для изготовления трубопроводов или других композиционных узлов. Интересно, что ОДУ рассматривается так же, как возможный кандидат для использования в термоядерных устройствах. Окисные частицы служат как межфазные ловушки для закрепления движущихся дислокаций. Поэтому сопротивление ползучести увеличивается. В случае использования этих материалов в реакторе их поведение под облучением должно изучаться более тщательно. В предлагаемой работе исследуются эффекты, обусловленные внедрением Не. Измеряется обусловленное распухание и механические характеристики облученной поверхности. Эти первые испытания были выполнены при комнатной температуре, когда можно явно наблюдать распухание и упрочнение

The influence of slice thickness and reconstruction kernel on dose optimisation of hepatic lesion computed tomography (CT) protocols

Purpose: To determine if phantom-based methodologies for dose-optimisation of CT liver protocols require randomisation of lesion location, and to explore the combined influence of current-time-product (mAs), slice thickness and reconstruction algorithm on hepatic lesion detection with CT. Methods: A CT liver phantom containing opacities (diameters 9.5 mm, 4.8mm, 2.4 mm; CT density 10 HU below background) was scanned at different mAs levels and the data reconstructed at 5 mm, 3 mm and 1 mm slice thicknesses and with three reconstruction algorithms: standard filtered backprojection (FBP), smoothing FBP and hybrid FBP/iterative reconstruction. To investigate the first aim, observer performance for the detection of the opacities in two image sets were compared: the first set contained images with known opacity location, the second set contained images with randomly positioned opacities. For the second aim, observer performance for opacity detection at the various combinations of mAs, slice thickness and reconstruction algorithm were compared to that for the standard setting. Results: When conditions were unambiguous (i.e. lesions were very obvious or invisible), lesion presentation method (known or unknown location) did not affect observer performance. Under difficult perception conditions, known lesion location was associated with poor observer agreement. Slice thickness of 5 mm provided better dose optimisation than 3mm and 1mm slice thicknesses. Standard FBP performed better than smoothing FBP and hybrid FBP/iterative at 5 mm, similar to hybrid FBP/iterative and better than smoothing FBP at 3 mm, and similar to both alternate methods at 1 mm. Conclusions: For routine hepatic protocols, dose optimisation can be performed with fixed lesion location. For protocols aimed at detecting very small lesions or providing very low dose, randomised lesion location is warranted. To optimise patient doses for routine liver examinations it is recommended to avoid the use of very thin slice thicknesses. A smoothing FBP kernel and a hybrid FBP/iterative kernel did not provide superior dose optimisation than the standard FBP algorithm