Microwave methods of measuring changes in lung water.

Area of Science:

• Biomedical Engineering
• Medical Physics
• Diagnostic Imaging

Background:

• Accurate measurement of lung water content is crucial for diagnosing and managing various respiratory conditions.
• Existing methods for assessing lung hydration may have limitations in sensitivity or invasiveness.

Purpose of the Study:

• To investigate the feasibility of two non-invasive microwave-based methods for quantifying changes in lung water content.
• To evaluate the sensitivity and potential clinical applicability of active microwave transmission and microwave radiometry for lung diagnostics.

Main Methods:

• Active microwave method: Measured changes in the phase of a transmitted microwave signal through the thorax.
• Radiometer method: Measured natural microwave radiation emitted by the body.
• Both methods were tested using phantoms, anesthetized dogs with induced pulmonary edema, and isolated dog lungs.

Main Results:

• The active microwave method demonstrated sensitivity to small changes in lung water content.
• Calculations and phantom measurements for the radiometer method indicated sensitivity to as little as 3-4% change in lung water content.
• Both methods showed promising initial results, validating the core concepts.

Conclusions:

• Both active microwave and radiometer methods are viable for detecting changes in lung water content.
• The findings support further development of these microwave techniques for clinical use in respiratory monitoring.