Manipulator-driven selection of semi-active MR-visible markers

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Robotics

Background:

• A novel method for identifying semi-active fiducial magnetic resonance (MR) markers is introduced.
• The technique relies on selectively optically tuning and detuning these markers.

Purpose of the Study:

• To present a new method for identifying semi-active fiducial magnetic resonance (MR) markers.
• To demonstrate the applicability of this technique in MR-compatible actuated devices.

Main Methods:

• Four solenoid coils with photoresistors were connected to light sources and controlled by a microcontroller.
• The microcontroller synchronized the optical tuning/detuning of coils with MR image acquisition.
• Markers were tested on an MR manipulator, linking control to joint actuation for marker subset selection.

Main Results:

• In closed-loop control, rotational joint errors averaged 0.76° ± 0.41° (maximum 1.18°).
• Prismatic joint errors averaged 0.87 mm ± 0.26 mm (maximum 1.13 mm).

Conclusions:

• The presented technique is suitable for MR-compatible actuated devices.
• It effectively utilizes semi-active MR-compatible markers for precise identification.