Lightweight Force-Controlled Device for Freehand Ultrasound Acquisition

Area of Science:

• Medical Imaging Technology
• Biomedical Engineering
• Ultrasound Physics

Background:

• Freehand ultrasound examinations require consistent probe pressure for optimal image quality and reproducibility.
• Sonographer fatigue and variability in manual pressure application can compromise diagnostic accuracy.
• Existing ultrasound systems lack dedicated mechanisms for precise force control during examinations.

Purpose of the Study:

• To develop and validate a force-controlled auxiliary device for freehand ultrasound (US) examinations.
• To enhance US image quality, reproducibility, and sonographer comfort.
• To enable precise and stable pressure application during prolonged or complex US procedures.

Main Methods:

• A lightweight, portable device utilizing a screw motor and Raspberry Pi controller was designed.
• Advanced control algorithms including gravity/error compensation and adaptive PID control were implemented for accurate force regulation.
• Low-pass signal filtering and a user-interactive screen were integrated for enhanced performance and usability.
• Clinical trials on jugular and superficial femoral veins were conducted to assess device efficacy.

Main Results:

• The device achieved highly accurate force control, maintaining desired pressure across varying conditions and durations.
• Experimental results validated the device's utility in improving US image stability and reproducibility.
• The system demonstrated significant reduction in sonographer hand joint stress and enabled rapid tissue elasticity assessment.
• Automatic pressure tracking between probe and patient was successfully implemented.

Conclusions:

• The force-controlled auxiliary device significantly enhances the reproducibility and stability of ultrasound images.
• The technology offers substantial benefits for sonographer health by reducing physical strain during examinations.
• This innovation has the potential to lower the clinical experience threshold for performing high-quality ultrasound scans.