Benigno Barbés

Universidad de Navarra | UNAV · Department of Oncology

Purpose: To investigate ion recombination correction and polarity effects in four ion chamber models in flattening-filter-free (FFF) beams to (1) evaluate their suitability for reference dosimetry; (2) assess the accuracy of the two-voltage technique (TVA) against the Bruggmoser formalism; and (3) examine the influence of the accelerator type on t...

Purpose To use four‐dimensional (4D) dose accumulation based on deformable image registration (DIR) to assess dosimetric uncertainty in lung stereotactic body radiation therapy (SBRT) treatment planning. A novel concept, the Evaluation Target Volume (ETV), was introduced to achieve this goal. Methods The internal target volume (ITV) approach was u...

Radiotherapy can be synergistically combined with immunotherapy in mouse models, extending its efficacious effects outside of the irradiated field (abscopal effects). We previously reported that a regimen encompassing local radiotherapy in combination with anti-CD137 plus anti-PD-1 mAbs achieves potent abscopal effects against syngeneic transplante...

Background Frameless Stereotactic Radiosurgery (FL-SRS) is a feasible procedure for the management of brain metastases (BM), delivering a single large radiation dose to a well-defined target. We aimed to assess its role as a first treatment option in recurrent brain metastases (r-BM) previously treated with SRS, WBRT or metastasectomy with or witho...

Background The impact of hypofractionated radiation therapy (HFRT) in elderly glioblastoma patients has recently been investigated, aiming to reduce the overall treatment time in this poor-prognosis group. There is evidence supporting that HFRT is comparable to conventional radiotherapy in terms of outcome and safety. The purpose of our study was t...

Background: Combination immunotherapy has the potential to achieve additive or synergistic effects. Combined local injections of dsRNA analogues (mimicking viral RNA) and repeated vaccinations with tumor-lysate loaded dendritic cells shows efficacy against colon cancer mouse models. In the context of immunotherapy, radiotherapy can exert beneficia...

Background In 2014, Siemens developed a new software-based scatter correction (Progressive Reconstruction Intelligently Minimizing Exposure [PRIME]), enabling grid-less digital mammography. Purpose To compare doses and image quality between PRIME (grid-less) and standard (with anti-scatter grid) modes. Material and Methods Contrast-to-noise ratio...

Purpose/objectives: Preclinical and clinical evidence indicate that the proimmune effects of radiotherapy can be synergistically augmented with immunostimulatory monoclonal antibodies (mAb) to act both on irradiated tumor lesions and on tumors at distant, nonirradiated sites. We have recently reported that external beam radiotherapy achieves absco...

This study aimed to describe the commissioning of small field size radiosurgery cones in a 6-MV flattening filter free (FFF) beam and report our measured values. Four radiosurgery cones of diameters 5, 10, 12.5, and 15 mm supplied by Elekta Medical were commissioned in a 6-MV FFF beam from an Elekta Versa linear accelerator. The extraction of a ref...

Purpose/Objectives The goal of this study was to assess the effects of ionizing radiation on the expression of the integrin ligands ICAM-1 and VCAM that control leucocyte transit by lymphatic endothelial cells. Materials/Methods Confluent monolayers of primary human lymphatic endothelial cells (LEC) were irradiated with single dose of 2, 5, 10 or...

Preclinical and clinical evidence indicate that the proimmune effects of radiotherapy can be synergistically augmented with immunostimulatory monoclonal antibodies (mAb) to act both on irradiated tumor lesions and on distant, non-irradiated tumor sites. The combination of radiotherapy with immunostimulatory anti-PD1 and anti-CD137 mAbs was conduciv...

Radiotherapy is considered an efficacious local tool to erradicate or at least control cancer progression. However, recent lines of preclinical and clinical evidence indicate that proimmune effects of radiotherapy can be synergistically augmented with immunostimulatory monoclonal antibodies (mAb) to act both on irradiated tumor lessions and on dist...

Purpose:The extraction of a reference signal for measuring small fields in scanning mode can be problematic. In this work we describe the use of a transmission chamber in small field dosimetry for radiosurgery collimators and compare TMR curves obtained with stereotactic diode and microionization chamber. Methods:Four radiosurgery cones of diameter...

Purpose:To calculate the total planning dose on lung tumors (GTV) by accumulating the dose received in all respiration phases. Methods:A patient 4D planning CT (phase-binned, from a Siemens Somatom CT) was used to locate the GTV of a lung tumor in all respiratory phases with Pinnacle (v9.10). GTV contours defined in all phases were projected to the...

Objectives: The aim of this study was to assess the dose received by members of the public due to close contact with patients undergoing nuclear medicine procedures during radiopharmaceutical incorporation, and comparing it with the emitted radiation dose when the test was complete, in order to establish recommendations. Material and methods: A...

This paper presents a method to obtain the pencil-beam kernels that characterize a megavoltage photon beam generated in a flattening filter free (FFF) linear accelerator (linac) by deconvolution from experimental measurements at different depths. The formalism is applied to perform independent dose calculations in modulated fields. In our previous...

Resumen Objetivos Evaluar la dosis que pueden recibir los miembros del público debido al contacto con pacientes de medicina nuclear durante la incorporación del radiofármaco y compararla con la dosis impartida una vez finalizado el estudio, con el fin de establecer recomendaciones. Material y métodos Se estudiaron 194 pacientes de forma prospecti...

A simple and independent system to detect and measure the position of a number of points in space was devised and implemented. Its application aimed to detect patient motion during radiotherapy treatments, alert of out‐of‐tolerances motion, and record the trajectories for subsequent studies. The system obtains the 3D position of points in space, th...

To assess the influence of reconstruction algorithms and parameters on the PET image quality of brain phantoms in order to optimize reconstruction for clinical PET brain studies in a new generation PET/CT. The 3D Hoffman phantom that simulates (18)F-fluorodeoxyglucose (FDG) distribution was imaged in a Siemens Biograph mCT TrueV PET/CT with Time of...

Purpose: To devise and implement a new system to measure and register the patient motion during radiotherapy treatments. Methods: The system can obtain the position of several points in the 3D-space, through their projections in the 2D-images recorded by two cameras. The algorithm needs a series of constants, that are obtained using the images of a...

Thermal conductivities and specific heat capacities of nanoparticles of Al2O3 dispersed in water and ethylene glycol as a function of the particle volume fraction and at temperatures between 298 and 338 K were measured. The steady-state coaxial cylinders method, using a C80D microcalorimeter (Setaram, France) equipped with special calorimetric vess...

A study of thermal properties of CuO dispersed in water and ethylene glycol as a function of the particle volume fraction and at temperatures between 298 and 338 K has been performed. Thermal conductivities have been studied by the steady-state coaxial cylinders method, using a C80D microcalorimeter (Setaram, France) equipped with special calorimet...

Purpose: External beam radiation therapy (EBRT) usually uses heterogeneous dose distributions in a given volume. Designing detectors for quality control of these treatments is still a developing subject. The size of the detectors should be small to enhance spatial resolution and ensure low perturbation of the beam. A high uniformity in angular res...

Introducción En la planificación de los implantes de braquiterapia prostática de alta tasa (HDR) es necesaria una optimización de los tiempos y posiciones de parada de la fuente, para una configuración dada de agujas, con el fin de cumplir con las restricciones impuestas a la dosimetría. Se han propuesto algoritmos que realizan esta optimización y...

A study has been carried out of calorimetric cells based on the coaxial cylinder method suitable for the thermal conductivity measurements in a C80D micro-calorimeter from Setaram (France). On the hypothesis of a pure conductive process, it has been possible to obtain the equation expressing the thermal conductivity k of a liquid sample in functio...

A study of a steady-state method for thermal conductivity measurements of liquids has been carried out. It uses a C80D differential micro-calorimeter from Setaram (France), with special designed vessels containing a heating resistance. The thermal conductivity k of a liquid sample is determined as a function of the heat flow measured by the calorim...

The dispersion and stability of nanofluids obtained by dispersing Al ₂ O ₃ nanoparticles (obtained from different sources) in water have been analyzed. The differences arising from different dispersion techniques, the resulting particle size distribution, and time stability among the different samples are evaluated. Then the v...

Several, widely used, group contribution models have been used to predict solid-liquid equilibria for n-alcohol+n-alkane binary mixtures. They are: modified UNIFAC [1], DISQUAC [2, 3], Nitta-Chao [4] and the Hole Model (HM) [5]. Also a recently reported group contribution model (AssoDis) including association [6] has been taken into account. The re...

The excess molar volume at 298.15K and atmospheric pressure for three (alkoxyethanol + toluene) mixtures have been determined over the whole mole fraction range from densities measured with a vibrating-tube densimeter. The alkoxyethanols were 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol. The three excess volumes curves have a maximum in th...

The excess volumes VE at the temperature 298.15 K for three (alkoxyethanol + toluene) mixtures have been measured over the whole mole-fraction range from densities measured with a vibrating-tube densimeter. The alkoxyethanol was 2-(2-methoxyethoxy)ethanol or 2-(2-ethoxyethyoxy)ethanol or 2-(2-butoxyethoxy)ethanol. The excess volumes curves are sigm...