ABSTRACT
The effect of relaxation time in hyperbolic heat transfer model on the temperature field of microwave ablation of atrial fibrillation was investigated. And the results were compared with those calculated by Pennes model. A three-dimensional model of microwave ablation of atrial fibrillation was constructed. The relaxation time (
Subject(s)
Humans , Atrial Fibrillation/surgery , Catheter Ablation , Hot Temperature , Microwaves , Radiofrequency Ablation , TemperatureABSTRACT
The temperature during the brain tumor therapy using high-intensity focused ultrasound (HIFU) should be controlled strictly. This research aimed at realizing uniform temperature distribution in the focal region by adjusting driving signals of phased array transducer. The three-dimensional simulation model imitating craniotomy HIFU brain tumor treatment was established based on an 82-element transducer and the computed tomography (CT) data of a volunteer's head was used to calculate and modulate the temperature distributions using the finite difference in time domain (FDTD) method. Two signals which focus at two preset targets with a certain distance were superimposed to emit each transducer element. Then the temperature distribution was modulated by changing the triggering time delay and amplitudes of the two signals. The results showed that when the distance between the two targets was within a certain range, a focal region with uniform temperature distribution could be created. And also the volume of focal region formed by one irradiation could be adjusted. The simulation results would provide theoretical method and reference for HIFU applying in clinical brain tumor treatment safely and effectively.
ABSTRACT
Objective Mobile operating compartment with overpressure protection can provide a safety environment for the patients and the surgical team by minimizing the risk of biochemical contamination through appropriate air filtration, steady overpressure foundation and air distribution scheme. Methods The air movement and the temperature distribution inside the mobile operating compartment with the overpressure protection performance were simulated by the technique of computational fluid dynamics(CFD), the air pattern and the temperature distribution were analyzed. Results The air velocity was under 0.5m/s in the most zone of person activity and the air velocity were distributed uniformly in the mobile operating compartment under the condition of the overpressure protection system. The obvious temperature gradient didn't exist in the vertical plane of the mobile operating compartment. The temperature distribution in the mobile operating compartment was quite uniform and the temperature was almost at 27℃ with the temperature difference of almost 2℃. Conclusion The human thermal comfort is good in the mobile operating compartment and the environment in the mobile operating compartment can satisfy requirements of the operation.