An MR-compatible force sensor based on FBG technology for biomedical application.

Area of Science:

• Biomedical Engineering
• Optical Sensing
• Materials Science

Background:

• Fiber Bragg Grating (FBG) technology offers robust sensing for thermal and mechanical parameters, especially in environments with electromagnetic interference.
• Developing sensors compatible with Magnetic Resonance (MR) imaging is crucial for advanced biomedical applications.

Purpose of the Study:

• To design, develop, and experimentally characterize novel force sensors utilizing FBG technology.
• To ensure the sensors are compatible with Magnetic Resonance imaging environments.
• To evaluate two distinct prototype designs for force measurement in biological applications.

Main Methods:

• Fabrication and testing of two FBG-based force sensor prototypes.
• Prototype 1: FBG fiber encapsulated in a polydimethylsiloxane (PDMS) sheet.
• Prototype 2: Free FBG fiber, with a differential configuration to mitigate temperature effects.

Main Results:

• The PDMS-encapsulated prototype exhibited a significantly wider measurement range (4200 mN) and good linearity, but lower sensitivity (≈0.1 nm/N).
• The free fiber prototype, using a differential configuration, showed improved linearity and temperature independence, though with reduced sensitivity (7 nm/N).
• Both prototypes demonstrated favorable metrological properties for force measurement in biomedical settings.

Conclusions:

• The developed FBG force sensors are suitable for biomedical applications, particularly where electromagnetic interference is a concern.
• The choice between the PDMS-encapsulated and free fiber designs depends on the specific application requirements regarding measurement range, sensitivity, and linearity.
• These sensors represent a promising advancement for accurate force measurement during MR-guided procedures and other biomedical applications.