A haptic unit designed for magnetic-resonance-guided biopsy

Area of Science:

• Medical Mechatronics
• Magnetic Resonance Imaging (MRI)
• Surgical Robotics

Background:

• Magnetic Resonance (MR) environments pose significant challenges for mechatronic devices due to strong magnetic fields.
• Spatial constraints in closed-bore scanners necessitate separation between clinicians and patients, leading to a loss of tactile feedback.
• Restoring haptic feedback is crucial for improving diagnostic accuracy and procedural precision in MR-guided interventions.

Purpose of the Study:

• To develop and evaluate an MR-compatible haptic unit for integration with a mechatronic system for MR-guided prostate biopsy.
• To enable position control and force feedback to the operator within the MR environment.
• To assess the feasibility of measuring tissue stiffness for diagnostic purposes.

Main Methods:

• Designed and constructed an MR-compatible haptic unit for integration into a five-degrees-of-freedom mechatronic system.
• Positioned the haptic unit within the MR scanner's isocenter and the master console in the control room.
• Validated MR compatibility by assessing signal-to-noise ratio and geometric distortion.
• Combined data from position encoders and force sensors for tissue stiffness measurement.

Main Results:

• Demonstrated negligible degradation of signal-to-noise ratio and virtually no geometric distortion, confirming MR compatibility.
• Successfully provided position control and force feedback to the operator.
• Achieved tissue stiffness measurement along a needle trajectory in lamb liver, differentiating tissue properties.

Conclusions:

• The developed MR-compatible haptic unit is suitable for MR-guided prostate biopsy, restoring tactile sensation.
• The system facilitates accurate tissue stiffness measurement, potentially aiding in the diagnosis of cancerous tissues.
• This technology enhances the capabilities of MR-guided interventions by integrating haptic feedback and diagnostic measurements.