A new geometrical method for 3D evaluation of non-rigid registration methods for radiotherapy in prostate cancer

Three-dimensional conformal radiotherapy aims at delivering a high dose of radiation to the tumour, while sparing the surrounding normal tissue to a maximum extent. Image registration is an essential tool for monitoring radiation therapies, since allows morphological comparisons in presence of anatomic variations. The evaluation of non-rigid registration methods is very complicated owe to the absence of a known pointwise correspondence. The use of analysis of variations in target volume delineations has been proposed in the past for the evaluation of non-rigid registration methods. Delineation of the target volume is usually accomplished by outlining the contour of the volume in each separate tomographic slice. In the studies of reference, the 3D surface is rendered from the contours by means of a Delauney triangulation. This geometrical method only works correctly for convex structures. However the volumes involved on pelvic anatomy, such as bladder or prostate including the seminal vesicles, have relevant concavities that introduce a huge error in the evaluation. A new geometrical method for the evaluation of convex-concave target volumes delineation is proposed

Quality of care assessment in COPD. AUDIPOC: the Spanish audit experience

There is now general knowledge illustratinga gap between the health care that patients rece-ive and the practice that is recommended by clinical guidelines [...

A new method for quantitative evaluation of target volume variations in radiotherapy planning

A new method for three-dimensional quantitative evaluation of target volume delineation is presented. It is composed by a new 3D reconstruction method called Origami, based on the combination of two bidimensional analysis of the volume of each organ instead of one 3D analysis, and a 3D description of the error distribution in the space. The Origami method avoid external errors introduced by a 3D rendering and has shown to work correctly in both convex and convex-concave volumes, accurately fitting the contours of the planning study. Its performance has been evaluated comparing it with the Convex Hull algorithm using Delaunay triangulation, resulting in a much more adjusted evaluation. Moreover, Origami computes thousands of control points in less than one second in a common PC

Ensayo para la determinación del estado de conservación de la vegetación

The constant search of strategies that they lead towards the sustainable development makes the environmental indicators exposition more and more frequent. The target of these indicators is to give useful information for the control of the conservation of the environment. The use of formulae that allow quantifying the conservation of the vegetation makes possible the securing of an indicative value of the state of naturalness of the vegetation. Also, the use of natural types of habitat instead of phytosociology associations allows simplifying the proposed formulation, obtaining completely valid results. Finally, the effect of the change of scale in the calculation of the value of the index does not suppose changes in the validity of the obtained value. Nevertheless, we must consider that the values obtained are only comparable in works realized to equal scale

Estación de trabajo para registro 3D y fusión de imágenes para la planificación de radioterapia

Este trabajo presenta una estación de trabajo para registro tridimensional y fusión de imágenes orientada a la ayuda en la planificación y monitorización de terapias de radiación externa. El concepto de radioterapia adaptativa propone la realización de una planificación del tratamiento en cada una de las sesiones a las que acude el paciente, lo que supondría un decremento importante en la radiación que afecta a los tejidos sanos circundantes al tumor y por tanto, una mejora significativa en la evolución de estos pacientes. Para reducir el tiempo que conlleva la delineación manual de los volúmenes de interés en la realización de una nueva planificación en cada sesión, la herramienta en la que se debe basar la radioterapia adaptativa es el registro tridimensional deformable de estudios CT para radioterapia. El prototipo que se presenta en este artículo permite el registro de imágenes DICOM mediante algoritmos no rígidos, su visualización, la comparación cualitativa de los resultados mediante fusión de imágenes, selección de regiones de interés en las imágenes y el almacenamiento de resultados en formato DICOM, visualizables por cualquier otro lector. El empleo de esta estación de trabajo, en combinación con algoritmos de reconstrucción tridimensional y segmentación automática desarrollados dentro del grupo, supone una gran ayuda en los procesos previos de la planificación radioterápica

Método de evaluación cuantitativa de algoritmos de registro tridimensional deformable

Se presenta una nueva metodología de evaluación cuantitativa de algoritmos de registro tridimensional deformable basada en las delineaciones de los órganos de interés. Esta metodología ofrece una completa descripción tridimensional del error de registro mediante el cálculo de las distancias entre los volúmenes del órgano de interés en la imagen de referencia y la imagen registrada. El método propuesto ha demostrado la capacidad de trabajar correctamente tanto en volúmenes totalmente convexos como en volúmenes cóncavo-convexos, ajustándose de manera precisa a los volúmenes marcados por el especialista. Además, el alto rendimiento del método permite la rápida evaluación en un gran número de direcciones de control (64800 direcciones en menos de un segundo

Ostracods as palaeoenvironmental tracers: evolution of the southern area of the Doñana National Park from the lower Pliocene to recent

El estudio de los materiales geológicos y las asociaciones de ostrácodos presentes en un testigo largo obtenido en el sur del Parque Nacional de Doñana (SO de España) permite inferir una evolución paleoambiental desde medios marinos someros (Plioceno Inferior) hasta un lagoon salobre (Pleistoceno Superior-Holoceno) y la implantación de sistemas eólicos (<1.900 años BP), con un estadio intermedio aluvial durante la mayor parte del Pleistoceno. En el Holoceno Superior, se detecta un evento tsunami- génico caracterizado por la erosión de sedimentos eólicos y su depósito sobre medios submarealesThe analysis of the geological units and the ostracod assemblages of a long core collected in the southern Doñana National Park (SW Spain) permits to deduce an evolution from shallow marine palaeoenvironments (Lower Pliocene) to a brackish lagoon (Upper Pleistocene-Holocene) and the deposit of aeolian sediments (<1900 yr BP), with an intermediate alluvial stage during the Pleistocene. In the Late Holocene, a tsunamigenic event was detected, with the erosion of aeolian sediments and a subsequent deposit on subtidal environment

Adsorption of salmonella in clay minerals and clay-based materials

A series of clay minerals and clay-based materials have been tested to eliminate one of the most dangerous bacteria we can find in the water: Salmonella. It has been proven that the use of clays and their PCH materials can be a suitable method for removing Salmonella from water. The results of this initial study show that all the materials analyzed have great salmonella adsorption capacities ranging from the lowest value observed in the mont-PCH sample (0.29 × 1010 CFU g−1 ) to the highest value observed in the natural palygorskite sample (1.52 × 1010 CFU g−1 ). Macroporosity, accessible external surface area, and the presence of silanol groups in the external surface of the particles appears to be the controlling factors for Salmonella adsorption capacity while it seems that the structural characteristics of the clay minerals and their respective PCH does not affect the adsorption capacityThe authors wish to thank the project BIA2017-82391-R for the financial suppor

Evolutionary-based prediction interval estimation by blending solar radiation forecasting models using meteorological weather types

Recent research has shown that the integration or blending of different forecasting models is able to improve the predictions of solar radiation. However, most works perform model blending to improve point forecasts, but the integration of forecasting models to improve probabilistic forecasting has not received much attention. In this work the estimation of prediction intervals for the integration of four Global Horizontal Irradiance (GHI) forecasting models (Smart Persistence, WRF-solar, CIADcast, and Satellite) is addressed. Several short-term forecasting horizons, up to one hour ahead, have been analyzed. Within this context, one of the aims of the article is to study whether knowledge about the synoptic weather conditions, which are related to the stability of weather, might help to reduce the uncertainty represented by prediction intervals. In order to deal with this issue, information about which weather type is present at the time of prediction, has been used by the blending model. Four weather types have been considered. A multi-objective variant of the Lower Upper Bound Estimation approach has been used in this work for prediction interval estimation and compared with two baseline methods: Quantile Regression (QR) and Gradient Boosting (GBR). An exhaustive experimental validation has been carried out, using data registered at Seville in the Southern Iberian Peninsula. Results show that, in general, using weather type information reduces uncertainty of prediction intervals, according to all performance metrics used. More specifically, and with respect to one of the metrics (the ratio between interval coverage and width), for high-coverage (0.90, 0.95) prediction intervals, using weather type enhances the ratio of the multi-objective approach by 2%¿. Also, comparing the multi-objective approach versus the two baselines for high-coverage intervals, the improvement is 11%¿% over QR and 10%¿% over GBR. Improvements for low-coverage intervals (0.85) are smaller.The authors are supported by projects funded by Agencia Estatal de Investigación, Spain (PID2019-107455RB-C21 and PID2019-107455RB-C22/AEI/10.13039/501100011033). Also supported by Spanish Ministry of Economy and Competitiveness, project ENE2014-56126-C2-1-R and ENE2014-56126-C2-2-R (http://prosol.uc3m.es). The University of Jaén team is also supported by FEDER, Spain funds and by the Junta de Andalucía, Spain (Research group TEP-220