A Radiation Force Balance Target Material for Applications below 0.5 MHz

Area of Science:

• Acoustics
• Medical Physics
• Materials Science

Background:

• Accurate measurement of acoustic output power is crucial for ultrasound safety, utilizing radiation force balances and specialized absorbing targets.
• International Standard IEC 61161 defines performance criteria for ultrasound absorbers, including transmission and reflection loss.
• A current deficiency exists in acoustic absorbers that meet these standards at frequencies below 0.5 MHz, hindering low-frequency therapeutic applications.

Purpose of the Study:

• To develop and characterize a novel acoustic absorber suitable for use below 0.5 MHz.
• To evaluate the absorber's performance against the requirements of IEC 61161 for transmission and reflection loss.

Main Methods:

• Development of a new acoustic absorber designed for low-frequency ultrasound absorption.
• Measurement of the absorber's transmission loss and reflection loss using two National Physical Laboratory facilities.
• Frequency range of characterization: 50-500 kHz.

Main Results:

• The developed acoustic absorber demonstrates effective performance in the low-frequency range.
• Transmission and reflection loss measurements were obtained between 50-500 kHz.
• The absorber meets IEC 61161 performance requirements down to approximately 120 kHz.

Conclusions:

• The new acoustic absorber is effective for use as a radiation force balance target at frequencies down to approximately 120 kHz.
• This innovation supports the development and safety assessment of emerging low-frequency therapeutic ultrasound applications.
• The study validates the material's efficacy in meeting critical international standards for acoustic absorption.