Advanced tracking and image registration techniques for intraoperative radiation therapy

Mención Internacional en el título de doctorIntraoperative electron radiation therapy (IOERT) is a technique used to deliver radiation to the surgically opened tumor bed without irradiating healthy tissue. Treatment planning systems and mobile linear accelerators enable clinicians to optimize the procedure, minimize stress in the operating room (OR) and avoid transferring the patient to a dedicated radiation room. However, placement of the radiation collimator over the tumor bed requires a validation methodology to ensure correct delivery of the dose prescribed in the treatment planning system. In this dissertation, we address three well-known limitations of IOERT: applicator positioning over the tumor bed, docking of the mobile linear accelerator gantry with the applicator and validation of the dose delivery prescribed. This thesis demonstrates that these limitations can be overcome by positioning the applicator appropriately with respect to the patient’s anatomy. The main objective of the study was to assess technological and procedural alternatives for improvement of IOERT performance and resolution of problems of uncertainty. Image-to-world registration, multicamera optical trackers, multimodal imaging techniques and mobile linear accelerator docking are addressed in the context of IOERT. IOERT is carried out by a multidisciplinary team in a highly complex environment that has special tracking needs owing to the characteristics of its working volume (i.e., large and prone to occlusions), in addition to the requisites of accuracy. The first part of this dissertation presents the validation of a commercial multicamera optical tracker in terms of accuracy, sensitivity to miscalibration, camera occlusions and detection of tools using a feasible surgical setup. It also proposes an automatic miscalibration detection protocol that satisfies the IOERT requirements of automaticity and speed. We show that the multicamera tracker is suitable for IOERT navigation and demonstrate the feasibility of the miscalibration detection protocol in clinical setups. Image-to-world registration is one of the main issues during image-guided applications where the field of interest and/or the number of possible anatomical localizations is large, such as IOERT. In the second part of this dissertation, a registration algorithm for image-guided surgery based on lineshaped fiducials (line-based registration) is proposed and validated. Line-based registration decreases acquisition time during surgery and enables better registration accuracy than other published algorithms. In the third part of this dissertation, we integrate a commercial low-cost ultrasound transducer and a cone beam CT C-arm with an optical tracker for image-guided interventions to enable surgical navigation and explore image based registration techniques for both modalities. In the fourth part of the dissertation, a navigation system based on optical tracking for the docking of the mobile linear accelerator to the radiation applicator is assessed. This system improves safety and reduces procedure time. The system tracks the prescribed collimator location to solve the movements that the linear accelerator should perform to reach the docking position and warns the user about potentially unachievable arrangements before the actual procedure. A software application was implemented to use this system in the OR, where it was also evaluated to assess the improvement in docking speed. Finally, in the last part of the dissertation, we present and assess the installation setup for a navigation system in a dedicated IOERT OR, determine the steps necessary for the IOERT process, identify workflow limitations and evaluate the feasibility of the integration of the system in a real OR. The navigation system safeguards the sterile conditions of the OR, clears the space available for surgeons and is suitable for any similar dedicated IOERT OR.La Radioterapia Intraoperatoria por electrones (RIO) consiste en la aplicación de radiación de alta energía directamente sobre el lecho tumoral, accesible durante la cirugía, evitando radiar los tejidos sanos. Hoy en día, avances como los sistemas de planificación (TPS) y la aparición de aceleradores lineales móviles permiten optimizar el procedimiento, minimizar el estrés clínico en el entorno quirúrgico y evitar el desplazamiento del paciente durante la cirugía a otra sala para ser radiado. La aplicación de la radiación se realiza mediante un colimador del haz de radiación (aplicador) que se coloca sobre el lecho tumoral de forma manual por el oncólogo radioterápico. Sin embargo, para asegurar una correcta deposición de la dosis prescrita y planificada en el TPS, es necesaria una adecuada validación de la colocación del colimador. En esta Tesis se abordan tres limitaciones conocidas del procedimiento RIO: el correcto posicionamiento del aplicador sobre el lecho tumoral, acoplamiento del acelerador lineal con el aplicador y validación de la dosis de radiación prescrita. Esta Tesis demuestra que estas limitaciones pueden ser abordadas mediante el posicionamiento del aplicador de radiación en relación con la anatomía del paciente. El objetivo principal de este trabajo es la evaluación de alternativas tecnológicas y procedimentales para la mejora de la práctica de la RIO y resolver los problemas de incertidumbre descritos anteriormente. Concretamente se revisan en el contexto de la radioterapia intraoperatoria los siguientes temas: el registro de la imagen y el paciente, sistemas de posicionamiento multicámara, técnicas de imagen multimodal y el acoplamiento del acelerador lineal móvil. El entorno complejo y multidisciplinar de la RIO precisa de necesidades especiales para el empleo de sistemas de posicionamiento como una alta precisión y un volumen de trabajo grande y propenso a las oclusiones de los sensores de posición. La primera parte de esta Tesis presenta una exhaustiva evaluación de un sistema de posicionamiento óptico multicámara comercial. Estudiamos la precisión del sistema, su sensibilidad a errores cometidos en la calibración, robustez frente a posibles oclusiones de las cámaras y precisión en el seguimiento de herramientas en un entorno quirúrgico real. Además, proponemos un protocolo para la detección automática de errores por calibración que satisface los requisitos de automaticidad y velocidad para la RIO demostrando la viabilidad del empleo de este sistema para la navegación en RIO. Uno de los problemas principales de la cirugía guiada por imagen es el correcto registro de la imagen médica y la anatomía del paciente en el quirófano. En el caso de la RIO, donde el número de posibles localizaciones anatómicas es bastante amplio, así como el campo de trabajo es grande se hace necesario abordar este problema para una correcta navegación. Por ello, en la segunda parte de esta Tesis, proponemos y validamos un nuevo algoritmo de registro (LBR) para la cirugía guiada por imagen basado en marcadores lineales. El método propuesto reduce el tiempo de la adquisición de la posición de los marcadores durante la cirugía y supera en precisión a otros algoritmos de registro establecidos y estudiados en la literatura. En la tercera parte de esta tesis, integramos un transductor de ultrasonido comercial de bajo coste, un arco en C de rayos X con haz cónico y un sistema de posicionamiento óptico para intervenciones guiadas por imagen que permite la navegación quirúrgica y exploramos técnicas de registro de imagen para ambas modalidades. En la cuarta parte de esta tesis se evalúa un navegador basado en el sistema de posicionamiento óptico para el acoplamiento del acelerador lineal móvil con aplicador de radiación, mejorando la seguridad y reduciendo el tiempo del propio acoplamiento. El sistema es capaz de localizar el colimador en el espacio y proporcionar los movimientos que el acelerador lineal debe realizar para alcanzar la posición de acoplamiento. El sistema propuesto es capaz de advertir al usuario de aquellos casos donde la posición de acoplamiento sea inalcanzable. El sistema propuesto de ayuda para el acoplamiento se integró en una aplicación software que fue evaluada para su uso final en quirófano demostrando su viabilidad y la reducción de tiempo de acoplamiento mediante su uso. Por último, presentamos y evaluamos la instalación de un sistema de navegación en un quirófano RIO dedicado, determinamos las necesidades desde el punto de vista procedimental, identificamos las limitaciones en el flujo de trabajo y evaluamos la viabilidad de la integración del sistema en un entorno quirúrgico real. El sistema propuesto demuestra ser apto para el entorno RIO manteniendo las condiciones de esterilidad y dejando despejado el campo quirúrgico además de ser adaptable a cualquier quirófano similar.Programa Oficial de Doctorado en Multimedia y ComunicacionesPresidente: Raúl San José Estépar.- Secretario: María Arrate Muñoz Barrutia.- Vocal: Carlos Ferrer Albiac

The caring enterprise: a sociology of corporate social involvement in Britain and Italy

This thesis examines corporate social responsibility initially in Britain, where there has recently been a conspicuous growth of interest in business social involvement, and Italy. Corporate social responsibility is defined here as business engagement in the wider community in order to contribute towards the general well-being of society. Our analysis employs a hybrid methodology: we employ a variety of sources, namely, historical texts, secondary studies and detailed case studies of corporate social programmes based on in-depth interviews of relevant personnel and the study of company documents. Our aim in this study is to provide a general explanation of why companies go beyond their commercial remit to become engaged in communitarian and philanthropic action. A socially and politically informed analysis is furnished: we place this area in its historical and political context, without losing sight of the role played by economic forces. Any explanation of contemporary advances in corporate social responsibility needs to stress the role of the modern state in society, and, more specifically, the development of relations between the state and the business community. It is argued that, in Britain, as a response to the political and economic crisis of the 1970s, the links between the business and state sectors became ever closer. This, as we shall demonstrate, created the institutional opportunities for active business involvement in society in areas such as environmental protection, small firm development and urban regeneration. Italy has seen less political impetus given to active corporate involvement in society. The most significant achievements, though, have come from within the state sector. A final consideration of our social analysis is that we attempt to analyse the contribution of the private sector to wider society. This is especially pertinent because, in Britain, corporate responsibility has come to be seen as a private solution to public problems. We show, using original case study material, that there are limits to what companies can achieve on a social front. We conclude that corporate social responsibility must emphasise the need for companies to observe social and legal restrictions in their pursuit of commercial goals, rather than necessarily engaging actively in social action

The academic as public intellectual: examining public engagement in the professionalised academy

In this article we critically consider the widely held conception that the public intellectual is in decline. We present a more sanguine fate of this figure, arguing that today we observe a flourishing of intellectuals. One such figure is the academic intellectual who has often been looked at with suspicion as a technical specialist. This conception suggests that university intellectuals are diluted versions of the historical conception of the ‘true’ public intellectual – that is, an ‘independent spirit’ that fearlessly challenges unjust power. In this article, we contest this view, arguing that this historical conception, idealised as it may be, nevertheless can inform scholastic activities. By resituating the public intellectual as a kind of temperament rather than a title, we examine its pressing – but at the same time uneasy – relevance to contemporary academic life. Counterposing this with contemporary instrumental conceptions of research impact, we suggest that where possible the intellectual academic should aspire to go beyond academic institutional norms and requirements. Hence, the academic public intellectual refers to a temperament, which is in but not of the academic profession

UN ASPETTO DELLA COMPRENSIONE: RICONOSCERE I PUNTI DI VISTA. COMPETENZA INDIVIDUALE CON VALORE SOCIALE

Partendo dalle difficoltà di comprensione di studenti del primo anno di università, l’autrice focalizza su una zona sensibile della semantica: l’individuazione di voci diverse in un testo. Si tratta dell’aspetto enunciativo del discorso, centrale quando l’avvicendamento dei punti di vista si avvicina alla polifonia. L’ipotesi didattica è che gli strumenti narratologici, ormai un po’ consunti, possano diventare delle leve per una didattica attiva di tipo laboratoriale che ponga gli studenti davanti a problemi interpretativi cui siano motivati a dare delle risposte.   One aspect of understanding: recognizing points of view. Individual competence with social value  Starting from the comprehension difficulties of first-year university students, the author focuses on a sensitive area of semantics: the identification of different voices in a text. This is the enunciative aspect of discourse, which is central when the alternation of points of view approaches polyphony. The didactic hypothesis is that the narratological instruments, now a bit worn out, can become levers for active, laboratory-type didactics that put students in front of interpretative problems which they are motivated to resolve

Juguetes y silbatos infantiles de época nazarí

El estudio presenta un número de piezas para uso infantil que nos ofrece el reflejo de la vida cotidiana, con representaciones figurativas de bulto redondo, tan escasas en el área hispanomusulmana (caballos, oso, reptiles...), a veces con silbatos adosados; y otros juegos para el uso de las niñas, que jugaban a imitación de sus madres a guisar, usando un completo ajuar de útiles de cocina y vajilla, presentando importantísimos ejemplos en este campo.This study presents a number of items for use by children, that give us images of daily life, with three-dimensional figures, so rare in the Hispano-Muslim period (horses, bears, reptiles...), some of them with whistles attached. Other toys are for use by girls, who played at imitating their mothers at cooking and used complete sets of kitchen utensils and crockery, thus providing us with important samples in this field

Enamels and other Narid metallic pieces

These pieces complete our knowledge of the high technical level of Nasrid artisans, very meticulous and original in their decoration, well enamelled and with colours on a gilded metallic base, also with incised or perforated decoration. All are small metalic items for personal use to enrich the appearance of their owners, mainly for masculine use, in belts for clothing or carrying of arms. Also metallic pieces that formed part of the protection of daggers and swords. For the house, these objects also completed the decoration of boxes and other domestic items.Estas piezas nos completan el conocimiento de la calidad técnica de los artesanos nazaríes, muy minuciosos y originales en la decoración, bien esmaltada y con colores sobre soporte metálico dorado, también decoración incisa o calada. Todas son pequeñas piezas metálicas para un uso personal que enriquecía el aspecto de sus dueños, fundamentalmente de uso masculino, en correajes para sus vestimentas o sujeción de sus armas. También aquellas piezas metálicas que formaban parte de la protección de puñales y espadas. Para las casas, estos objetos también completaban la decoración de cajas y otros enseres domésticos

Juguetes y silbatos infantiles de época nazarí

This study presents a number of items for use by children, that give us images of daily life, with three-dimensional figures, so rare in the Hispano-Muslim period (horses, bears, reptiles...), some of them with whistles attached. Other toys are for use by girls, who played at imitating their mothers at cooking and used complete sets of kitchen utensils and crockery, thus providing us with important samples in this field.El estudio presenta un número de piezas para uso infantil que nos ofrece el reflejo de la vida cotidiana, con representaciones figurativas de bulto redondo, tan escasas en el área hispanomusulmana (caballos, oso, reptiles...), a veces con silbatos adosados; y otros juegos para el uso de las niñas, que jugaban a imitación de sus madres a guisar, usando un completo ajuar de útiles de cocina y vajilla, presentando importantísimos ejemplos en este campo

SCHEMI E MACROSTRUTTURE DEL TESTO ESPOSITIVO: UN RUOLO ATTIVO NELLA COMPRENSIONE

L’articolo pone l’accento sull’importanza della macrostruttura nella comprensione del testo. Per arrivare alla sua costruzione, la mente compie una serie di operazioni linguistico-cognitive, avvalendosi non solo delle informazioni reperibili nel testo, ma anche di schemi della mente, fra i quali vi sono gli schemi testuali. Nei testi espositivi, dove non è individuabile una struttura testuale forte che guidi la comprensione, sono l’intelaiatura gerarchica delle informazioni e le connessioni logico-testuali tra le parti che aiutano a mettere a fuoco la macrostruttura. Il percorso didattico proposto, di tipo laboratoriale, rivolto a studenti del primo anno di università che devono assolvere agli Obblighi Formativi Aggiuntivi, cerca di seguire e supportare le tappe del processo di comprensione che portano dall’individuazione della coerenza locale alla rappresentazione semantica globale del testo.   Schemes and macrostructures in expository texts: an active role in understanding The article emphasizes the importance of the macrostructure in understanding texts. The mind performs a series of linguistic-cognitive operations, making use not only of information found in texts, but also mental schemes which include textual schemes. In expository texts, where a strong textual structure that guides comprehension cannot be identified, the hierarchical framing of information and the logical-textual connections between the parts help to bring the macrostructure into focus. The proposed workshop, for first year university students who need to fulfill the Additional Educational Obligations, tries to follow and support the stages of the comprehension process, from the identification of local coherence to the global semantic meaning of the text

El capitel almohade: importancia y consecuencias

This work studies the twelfth- and thirteenth-century Almohad capitals which, following the Hispano-Muslim tradition, use very evolved classical elements and lead to what will be the Nasrid capital and its Marinid parallels. The study analyses first the Almohad capitals of the Iberian Peninsula that are preserved but not in situ, among which those of the Granadine school stand out, as do the North African samples. The Nasrid capitals of the thirteenth century are shown to evolve directly from them, and in the fourteenth century, under the Sultanate of Muhammad V, a school of carvers turned again to the Almohad capital, reused some and imitated others.En este trabajo se estudian los capiteles del siglo XII-XIII almohades que siguiendo la tradición hispanomusulmana, toman muy evolucionadas características clásicas, abriendo paso a lo que será el capitel nazarí y sus paralelismos meriníes. En primer lugar se analizan los ejemplares almohades de la Península Ibérica conservados o no in situ, entre los que hay que destacar la escuela granadina, y los norteafricanos. Como ejemplo directo evolutivo se presentan los nazaríes del XIII y como en el XIV bajo el sultanato de Muhammad V, una escuela de tallistas retoma de forma recurrente ejemplares almohades, reutilizados algunos e imitados otros

Capiteles califales del museo Nacional de Arte Hispano-musulmán

A la hora de hacer un exhaustivo estudio del arte califal y concretamente de su decoración, no podemos dejar atrás un capítulo de tanta importancia como es el estudio del capitel desde los primeros momentos de la denominación musulmana.El capitel hispanomusulmán no llega a tomar unas características propias en los primeros momentos sino que se limitará a tomar como modelos ejemplares clásicos romanos y visigodos. Al iniciarse el califato los capiteles toman una tipología propia hispanomusulmana que evolucionará a lo largo de los siglos