MRI feedback temperature control for focused ultrasound surgery

Area of Science:

• Biomedical Engineering
• Medical Physics
• Surgical Technology

Background:

• Focused ultrasound surgery (FUS) requires precise temperature control to ensure efficacy and patient safety.
• Real-time temperature monitoring and feedback are critical for advanced FUS applications, particularly those guided by Magnetic Resonance Imaging (MRI).

Purpose of the Study:

• To develop and evaluate a novel temperature feedback controller routine for focused ultrasound surgery.
• To utilize a physical model based on Pennes' bioheat transfer equation for accurate temperature evolution prediction.
• To assess the controller's performance in simulated MRI-monitored FUS treatments.

Main Methods:

• Developed a multi-input, single-output linear quadratic regulator (LQR) algorithm.
• Integrated the LQR with a physical model of temperature evolution derived from Pennes' bioheat transfer equation.
• Tested the controller using simulated temperature data mimicking MRI acquisition characteristics.
• Simulated controller performance in 3D with varying system parameters.

Main Results:

• The controller demonstrated sufficient temperature tracking capabilities during simulated treatments.
• Worst-case temperature overshoot was recorded at 7 degrees C.
• Steady-state error in temperature control was observed to be 5 degrees C.
• Controller parameters were determined using pre-estimated tissue parameters.

Conclusions:

• The developed temperature feedback controller shows satisfactory performance in simulations.
• The controller's ability to manage transducer power output is promising for MRI-monitored ultrasound surgery.
• This controller may enhance the safety and precision of focused ultrasound interventions.