1065. Experimental Study on Thermal Field Distribution of Microwave Ablation in Homogenous Liquid Using Cyst-Mimicking Model
Authors * Denotes Presenting Author
  1. Bin Li *; Beijing Hospital
  2. Xiaoguang Li; Beijing Hospital
This study aimed to explore the thermal field distribution of microwave ablation (MWA) in a homogeneous liquid using a cyst-mimicking model.

Materials and Methods:
A total of twelve bladders of New Zealand white rabbits were used to mimic cysts, divided into a MWA experimental group (f = 5 cm, 60 W) and a control group. The antennas were introduced into the central position of the cyst-mimicking models. We measured the real-time temperature changes during the procedure and used an infrared thermal imaging device to dynamically monitor the thermal field distribution. The macroscopic and histological changes of the cyst-mimicking models were evaluated, and statistical analysis was conducted.

A total of ten cyst-mimicking models were performed with MWA, each with five temperature points, and two cases without MWA in the control group. There was a positive correlation between the temperature gradient of the cyst-mimicking model (wall and liquid) and MWA power. The temperature of the cystic left side wall was similar to the right-side wall (<em>P</em> > 0.05), and below the average of the cystic upper wall and liquid (<em>P</em> > 0.05), and significantly higher than the cystic lower wall (<em>P</em> < 0.05), with all temperature values eventually balanced. The microwave thermal field was regionally distributed in the cyst-mimicking model, and the region and extent of the thermal field were related to the ablation duration. The temperature of the cystic sidewall and liquid can reach the point of coagulative necrosis (> 70°C) when covered by the microwave thermal field. Histopathology of control group showed normal bladder epithelial cells and intracellular structural integrity, the morphology of lamina propria and muscle cell integrity; experimental group showed bladder wall epithelial cell degeneration and necrosis, and lamina propria and muscle layer of normal tissue structure were completely disappeared.

Microwave thermal energy was transmitted in the liquid by thermal convection, and the distribution of the thermal field in the homogeneous liquid was regional and uniform. MWA is a promising treatment for cystic lesions.