Browsing by Author "Lamien, Bernard"
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Item Estimation of the temperature field in laser-induced hyperthermia experiments with a phantom(Taylor and Francis Ltd, 2018-12-31) Lamien, Bernard; Orlande, Hélcio Rangel Barreto; Bermeo Varón, Leonardo A.; Rodrigo, Leite Queiroga Basto; Enrique Eliçabe, Guillermo; Silva Dos Santos, Dilson; Machado Cotta, RenatoBackground: One of the challenges faced during the hyperthermia treatment of cancer is to monitor the temperature distribution in the region of interest. The main objective of this work was to accurately estimate the transient temperature distribution in the heated region, by using a stochastic heat transfer model and temperature measurements. Methods: Experiments involved the laser heating of a cylindrical phantom, partially loaded with iron oxide nanoparticles. The nanoparticles were manufactured and characterized in this work. The solution of the state estimation problem was obtained with an algorithm of the Particle Filter method, which allowed for simultaneous estimation of state variables and model parameters. Measurements of one single sensor were used for the estimation procedure, which is highly desirable for practical applications in order to avoid patient discomfort. Results: Despite the large uncertainties assumed for the model parameters and for the coupled radiation–conduction model, discrepancies between estimated temperatures and internal measurements were smaller than 0.7 °C. In addition, the estimated fluence rate distribution was physically meaningful. Maximum discrepancies between the prior means and the estimated means were of 2% for thermal conductivity and heat transfer coefficient, 4% for the volumetric heat capacity and 3% for the irradiance. Conclusions: This article demonstrated that the Particle Filter method can be used to accurately predict the temperatures in regions where measurements are not available. The present technique has potential applications in hyperthermia treatments as an observer for active control strategies, as well as to plan personalized heating protocols. © 2018, © 2018 The Author(s). Published with license by Taylor & Francis Group, LLC.Item Real-time temperature estimation with enhanced spatial resolution during MR-guided hyperthermia therapy(Taylor and Francis Ltd., 2020-04-17) Pacheco, César C.; Barreto Orlande, Hélcio Rangel; Colaço, Marcelo José; Dulikravich, George S.; Bermeo Varón, Leonardo A.; Lamien, BernardIn this article, the temperature of biological tissues is estimated during hyperthermia therapy, while accounting for uncertainties in the bioheat transfer problem and in the available measurements. A state estimation problem is solved with the Steady-State Kalman Filter. The Pennes bioheat transfer model and the PRF-Shift Magnetic Resonance Thermometry are used as evolution and observation models, respectively. Instead of using the direct inversion of the measured data as with the PRF-Shift Magnetic Resonance Thermometry, the state-estimation framework allows for enhancing the spatial resolution of the estimated temperature variation and reducing the related uncertainties. Since the time consuming steps of the Steady-State Kalman Filter can be performed offline, the recursive solution of the state estimation problem is performed with computational times smaller than the simulated physical times. Synthetic measurements are used for the state estimation problem in a region of the human forearm, for radiofrequency and laser-diode heat sources of the hyperthermia therapy.Item Thermal Effect by Applying Laser Heating in Iron Oxide Nanoparticles Dissolved in Distilled Water(Springer, 2019-09-25) Bermeo Varon, Leonardo A.; Loiola, Bruna R.; da Silva Abreu, Luiz A.; Lamien, Bernard; da Silva, Nilton Pereira; da Silva, Nilton Pereira; Silva dos Santos, DilsonDue to their physical properties and biocompatibility, iron oxide nanoparticles have received particular attention in recent years for the localized hyperthermia therapy, where they are targeted to an organ, tissue or tumor and an external source is used for heating. Several physical, chemical and biological methods have been used to synthetize nanoparticles. A mechanical alloying method was used in this work to manufacture Fe2O3 nanoparticles. The size and shape of the nanoparticles were measured by scanning electron microscopy and X-ray diffraction. In this work, experiments were conducted with the nanoparticles dissolved in distilled water and heated by a laser in the near infrared range, with temperature measurements taken by an infrared camera. Numerical simulations were performed with COMSOL Multiphysics and compared to the experimental results. The numerical results agree with the measurements within the experimental uncertainties. The experimental results revealed a larger temperature increase of the sample surface for a larger concentration of nanoparticles. Hence, the Fe2O3 nanoparticles manufactured in this work behaved as a thermal agent with potential use for the hyperthermia therapy, including the treatment of cancer.