A Novel Nickel-Foam/Tungsten-Powder/Epoxy-Resin Backing Material for Medical Ultrasound Transducers

Area of Science:

• Materials Science
• Acoustics
• Biomedical Engineering

Background:

• Medical ultrasound transducer miniaturization is hindered by thick backing layers needed for acoustic energy dissipation.
• Conventional backing materials limit the development of smaller, more portable ultrasound devices.

Purpose of the Study:

• To develop a novel hybrid composite backing material for medical ultrasound transducers.
• To improve acoustic energy dissipation and enable transducer miniaturization.

Main Methods:

• Fabrication of a hybrid composite by interpenetrating nickel foam with tungsten-powder/epoxy-resin.
• Characterization of acoustic properties (attenuation, impedance) of composite samples with varying pores per inch (PPI).
• Evaluation of a 5 MHz transducer with the proposed backing material.

Main Results:

• The 100 PPI composite demonstrated high acoustic attenuation coefficients (62.6 dB/cm at 5 MHz, 84.2 dB/cm at 7.5 MHz), approximately three times higher than conventional materials.
• A suitable acoustic impedance of 10.81 MRayl was maintained.
• A 5.0 mm layer of the proposed backing achieved a -60 dB insertion loss, comparable to a 16.5 mm conventional backing, reducing axial dimension by over 60%.

Conclusions:

• The developed hybrid composite backing material effectively dissipates acoustic energy.
• This material enables significant reduction in backing layer thickness, facilitating the miniaturization of medical ultrasound transducers without compromising performance.
• Offers a viable solution for next-generation compact ultrasound imaging systems.