Strategies for adaptive radiotherapy: towards clinically efficient workflows

Adaptive radiotherapy (ART) aims to adapt the treatment plan to account for inter-fraction anatomical variations, based on online acquired images. However, ART workflows are not –yet– routinely used in clinical practice, primarily due to the dramatic increase of the workload required and the inadequate understanding of optimal methods to maximise clinical benefit. This thesis reports on investigations of procedures for the automation of the ART process and the identification of optimal adaptation methodologies. Investigated auto-segmentation algorithms were found insufficient for an automated workflow, while a hybrid deformable image registration (DIR), incorporating both intensity based and feature-based components, revealed the most accurate and robust performance. An evaluation method was proposed for interfraction treatment monitoring through dose accumulation following DIR. The robustness of several treatment methods to observable anatomical changes were investigated, highlighting cases whereby substantial dosimetric consequences may arise. Offline ART workflows were explored, specifically investigating the effects of treatment monitoring frequency, adaptation method (simple re-plan or re-optimisation addressing cumulative dose), and adaptation timing. Contrary to simple re-planning, re-optimisation demonstrated its ability to compensate for under-/over-dose, however, non-uniform dose distributions and hot-spots may be generated. Therefore established planning techniques are applicable for re-planning while advanced approaches are required for treatment re-optimisation accounting for radiobiological consequences

The influence of political power and ideology on quality evaluation policies in higher education

Purpose: The diversity of political views provides great opportunities for sound evaluation methods in higher education, since these are defined, enacted upon and funded through governmental processes; their implementation is constantly subjected to political pressures –This paper explores how results are evaluated as intended to occur many years after implementation of education policy and what is the role of critical political institutions such as accountability and transparency. Methods: We present as a case study the evolution of evaluation concepts in Greek universities, through a 35-year period, characterized by the shifting of political power. These observations are generalized by the results of interviews conducted with an international group of academics. Results: There is a strong link between political power and ideology and the determination of quality evaluation, leading to distinct and different outcomes, as implemented in national strategies for higher education, strongly affecting HEI’s in all aspects. Implications: In this paper we show how the state political control shapes the context of QA in universities. Universities must have the courage to protect their core values, democracy, transparency, accountability and the creation of knowledge

The influence of political power and ideology on quality evaluation policies in higher education

Purpose: The diversity of political views provides great opportunities for sound evaluation methods in higher education, since these are defined, enacted upon and funded through governmental processes; their implementation is constantly subjected to political pressures. This paper explores how results are evaluated as intended to occur many years after implementation of education policy and what is the role of critical political institutions such as accountability and transparency. Methods: We present as a case study the evolution of evaluation concepts in Greek universities, through a 35-year period, characterized by the shifting of political power. These observations are generalized by the results of interviews conducted with an international group of academics. Results: There is a strong link between political power and ideology and the determination of quality evaluation, leading to distinct and different outcomes, as implemented in national strategies for higher education, strongly affecting HEI’s in all aspects. Implications: In this paper we show how the state political control shapes the context of QA in universities. Universities must have the courage to protect their core values, democracy, transparency, accountability and the creation of knowledge. (DIPF/Orig.

Measuring Democratization and Detecting State Transitions

In the proposed research, an in-depth analysis of the features presented in six representative international organizations measuring democracy worldwide revealed a sizeable set of significant and complementary indicators that provided the basis for the construction of a common conceptual framework for democratization. The size and variety of the examined datasets overcomes any possible skepticism for data biasing. We also propose a method of combining such complementary or competing indicators using Multi-objective Optimization, in order to increase objectivity. The periodic monitoring of the proposed indicators allows for the detection of State Transitions, especially under alarming conditions. Our aim is to propose an objective tool for policy makers that would eliminate selective interpretation of democracy and its transitions, by allowing political change to be meaningfully understood in its proper perspective using facts and data

Current «policies of knowledge» in the European Union : mapping and critically assessing «quality» in a «measurable» Europe of knowledge

This paper investigates the content and the different «dimensions» of «quality» in the current «policies of knowledge» of the European Union as they are specified by the renewed Lisbon Strategy and in the frame of the construction of a «measurable Europe of Knowledge». The study analyses critically the policy discourses and policy practices of the European Union from 1994 to 2010 using both primary (e.g. official documents) and secondary (e.g. scholarly articles, studies and research) sources. It consists of four sections: The first section refers to the current constructions of quality discourse in the European context (e.g. globalization, knowledge economies and GATS, new public management, new governance, etc.). In the second section, we examine the integration of «quality» in the EU’s discourses and policies (Treaties, Action Programs as well as in the general, vocational and higher education initiatives). The third section reviews the quality discourse in the context of the late EU’s policy processes (Lisbon, Bologna and Copenhagen). In the final section we put forward a critical reading of the «audit/ quality» nexus based on a «policy by numbers» technocratic-managerial rationale aiming at the construction of a measurable «Europe of knowledge».Este artículo investiga el contenido y las diferentes «dimensiones» de «calidad» en las actuales «políticas de conocimiento» de la Unión Europea, del modo en que están especificadas por la renovada «Estrategia de Lisboa» y en el marco de la construcción de una «Europa del Conocimiento Medible ». El estudio analiza en profundidad los discursos políticos y las prácticas políticas de la Unión Europea desde 1994 hasta 2010, utilizando a la vez fuentes primarias (por ejemplo, documentos oficiales) y secundarias (por ejemplo, artículos, estudios e investigación académicos). Consta de cuatro secciones: La primera sección se refiere a las actuales construcciones del discurso sobre la calidad en el contexto Europeo (por ejemplo, globalización, economía del conocimiento, la nueva gestión pública, nuevos gobiernos, etc.). en la segunda sección, examinamos la integración de la «calidad» en los discursos y políticas de la UE (Tratados, Programas de Acción así como las iniciativas generales, vocacionales de la educación superior). La tercera sección revisa el discurso de la «calidad» en el contexto de los actuales procesos políticos de la UE (Lisboa, Bolonia, Copenhague). En la última sección, presentamos una lectura crítica del nexo «auditoría/calidad», basado en una «política de los números», de objetivo tecnocrático-gerencial de la construcción de una «Europa del conocimiento» medible

Modelling the Collapsing University

Although university’s contribution to the democratic society has been studied adequately, the establishment of its internal democratic institutions has not. Issues of autonomy and accountability exist whereas, today’s Postmodernism introduces further uncertainty. After constructing a framework for measuring democracy within a university using democracy indicators selected from international organizations, we attempt to interrelate these indicators to its democratic characteristics, raising the question: “To what extent could these characteristics be eroded before the university collapses?” Interviews with European academics were conducted and the influence of forces external to the university were studied using the Central European University in Hungary as a case study. The findings show that increased state control undermines institutional autonomy and so does imposing unnecessary restrictions. Protecting democracy and academic freedom, civil rights, and supporting an open society are of paramount importance, otherwise the university collapses. A model that captures such catastrophic state changes is finally proposed

Real-time Cherenkov emission portal imaging during CyberKnife® radiotherapy

The feasibility of real-time portal imaging during radiation therapy, through the Cherenkov emission (CE) effect is investigated via a medical linear accelerator (CyberKnife) irradiating a partially-filled water tank with a 60 mm circular beam. A graticule of lead/plywood and a number of tissue equivalent materials were alternatively placed at the beam entrance face while the induced Cherenkov emission (CE) at the exit face was imaged using a gated electron-multiplying-intensified-charged-coupled device (emICCD) for both stationary and dynamic scenarios. This was replicated on an Elekta Synergy® linear accelerator with portal images acquired using the iViewGT™ system. Profiles across the acquired portal images were analysed to reveal the potential resolution and contrast limits of this novel CE based portal imaging technique and compared against the current standard. The CE resolution study revealed that using the lead/plywood graticule, separations down to 3.4 ± 0.5 mm can be resolved. A 28 mm thick tissue-equivalent rod with electron density of 1.69 relative to water demonstrated a CE contrast of 15% through air and 14% through water sections, as compared to a corresponding contrast of 19% and 12% using the iViewGT™ system. For dynamic scenarios, video rate imaging with 30 frames per second was achieved. It is demonstrated that CE-based portal imaging is feasible to identify both stationary and dynamic objects within a CyberKnife radiotherapy treatment field

A clinical evaluation of the performance of five commercial artificial intelligence contouring systems for radiotherapy

Purpose/objective(s)Auto-segmentation with artificial intelligence (AI) offers an opportunity to reduce inter- and intra-observer variability in contouring, to improve the quality of contours, as well as to reduce the time taken to conduct this manual task. In this work we benchmark the AI auto-segmentation contours produced by five commercial vendors against a common dataset.Methods and materialsThe organ at risk (OAR) contours generated by five commercial AI auto-segmentation solutions (Mirada (Mir), MVision (MV), Radformation (Rad), RayStation (Ray) and TheraPanacea (Ther)) were compared to manually-drawn expert contours from 20 breast, 20 head and neck, 20 lung and 20 prostate patients. Comparisons were made using geometric similarity metrics including volumetric and surface Dice similarity coefficient (vDSC and sDSC), Hausdorff distance (HD) and Added Path Length (APL). To assess the time saved, the time taken to manually draw the expert contours, as well as the time to correct the AI contours, were recorded.ResultsThere are differences in the number of CT contours offered by each AI auto-segmentation solution at the time of the study (Mir 99; MV 143; Rad 83; Ray 67; Ther 86), with all offering contours of some lymph node levels as well as OARs. Averaged across all structures, the median vDSCs were good for all systems and compared favorably with existing literature: Mir 0.82; MV 0.88; Rad 0.86; Ray 0.87; Ther 0.88. All systems offer substantial time savings, ranging between: breast 14-20 mins; head and neck 74-93 mins; lung 20-26 mins; prostate 35-42 mins. The time saved, averaged across all structures, was similar for all systems: Mir 39.8 mins; MV 43.6 mins; Rad 36.6 min; Ray 43.2 mins; Ther 45.2 mins.ConclusionsAll five commercial AI auto-segmentation solutions evaluated in this work offer high quality contours in significantly reduced time compared to manual contouring, and could be used to render the radiotherapy workflow more efficient and standardized

The holistic perspective of the INCISIVE project : artificial intelligence in screening mammography

Finding new ways to cost-effectively facilitate population screening and improve cancer diagnoses at an early stage supported by data-driven AI models provides unprecedented opportunities to reduce cancer related mortality. This work presents the INCISIVE project initiative towards enhancing AI solutions for health imaging by unifying, harmonizing, and securely sharing scattered cancer-related data to ensure large datasets which are critically needed to develop and evaluate trustworthy AI models. The adopted solutions of the INCISIVE project have been outlined in terms of data collection, harmonization, data sharing, and federated data storage in compliance with legal, ethical, and FAIR principles. Experiences and examples feature breast cancer data integration and mammography collection, indicating the current progress, challenges, and future directions