MRI compatible head phantom for ultrasound surgery.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Acoustic Physics

Background:

• Focused ultrasound surgery (FUS) is an emerging therapeutic modality.
• MRI-guided FUS (MRgFUS) offers precise targeting for various applications, including brain cancer treatment and sonothrombolysis.
• Accurate phantoms are crucial for developing and validating FUS protocols.

Purpose of the Study:

• To develop an MRI-compatible head phantom with acoustic properties similar to human tissues.
• To create a phantom suitable for testing focused ultrasound surgery protocols.
• To reduce the need for animal and cadaver models in FUS research.

Main Methods:

• A 3D model of a human skull was created from CT scan data and printed using Acrylonitrile Butadiene Styrene (ABS) plastic.
• A novel gel mixture (agar-evaporated milk-silica gel) was developed to simulate cerebral tissue properties.
• The gel was molded within the 3D-printed skull to create the complete head phantom.

Main Results:

• The ABS skull exhibited an acoustic attenuation of 16 dB/cm MHz.
• The simulated brain tissue gel had an estimated attenuation coefficient of 0.6 dB/cm MHz.
• The phantom demonstrated effectiveness in reducing ultrasonic heating, validated by MRI thermometry.

Conclusions:

• The developed head phantom accurately mimics human acoustic attenuation.
• This phantom serves as a valuable tool for evaluating MRgFUS protocols.
• Its use can significantly decrease the necessity for animal and cadaver testing in FUS research.