A feasibility study for non-invasive thermometry using non-linear ultrasound

Area of Science:

• Acoustics
• Biomedical Engineering
• Medical Physics

Background:

• High intensity focused ultrasound (HIFU) is crucial for hyperthermia cancer treatment, requiring precise temperature monitoring.
• Non-invasive thermometry is essential for safe and effective HIFU applications.
• The acoustic non-linearity parameter B/A's potential for temperature measurement is explored.

Purpose of the Study:

• To investigate the suitability of the acoustic non-linearity parameter B/A for measuring temperature changes.
• To propose and demonstrate a novel non-invasive thermometry method based on B/A.

Main Methods:

• Water was used to validate B/A's sensitivity as an acoustic thermometry parameter.
• A thermometry method was developed using ratios of fundamental and harmonic acoustic wave components.
• Simulated plane wave propagation in glycerol was used to demonstrate the proposed method.

Main Results:

• B/A showed higher sensitivity to temperature changes in water compared to other acoustic parameters.
• The proposed method predicted temperature non-invasively with zero bias and a 2°C standard deviation under specific noise conditions.
• Simulated measurements confirmed the feasibility of the B/A-based thermometry approach.

Conclusions:

• The acoustic non-linearity parameter B/A is confirmed as a viable basis for non-invasive thermometry.
• A novel non-invasive thermometry method utilizing B/A was successfully proposed and demonstrated.
• This research supports the development of advanced monitoring techniques for HIFU cancer therapy.