Microwave radiometric thermometry and its potential applicability to ablative therapy

Area of Science:

• Biomedical Engineering
• Medical Physics
• Thermometry

Background:

• Current catheter tip temperature monitoring in cardiac ablation uses thermocouples/thermistors, which may not accurately reflect tissue temperature.
• These methods can miss critical temperature elevations away from the electrode during cooling, impacting treatment efficacy and safety.

Purpose of the Study:

• To evaluate microwave radiometric thermometry as a novel method for monitoring temperature at a distance from the catheter tip.
• To assess the feasibility of this technique in an in-vitro saline model for cardiac ablation therapy.

Main Methods:

• A microwave radiometer antenna and a fluoroptic thermometer were used in a saline model simulating cardiac ablation conditions.
• The radiometer's ability to detect temperature changes in a heated saline bath at varying distances (5 mm and 8 mm) was measured.

Main Results:

• The microwave radiometer accurately detected temperature increases in the surrounding saline bath.
• A strong correlation was observed between radiometer readings and actual bath temperatures (R²=0.997 at 5 mm, R²=0.991 at 8 mm).
• The fluoroptic thermometer, placed near the radiometer, did not register temperature changes in the distant heated bath.

Conclusions:

• Microwave radiometry can estimate temperatures at a distance by detecting microwave radiation.
• The sensitivity of microwave radiometric thermometry is distance-dependent.
• This technique is a promising tool for monitoring subsurface temperatures during cardiac ablation therapy, offering advantages over conventional methods.