Magnetic Resonance-compatible needle-like probe based on Bragg grating technology for measuring temperature during...

Area of Science:

• Biomedical Engineering
• Optical Sensing
• Medical Devices

Background:

• Accurate temperature monitoring during laser ablation (LA) is crucial for optimizing treatment outcomes.
• Fiber Bragg Grating (FBG) sensors offer high sensitivity, accuracy, and electromagnetic interference immunity for temperature sensing.
• FBG sensors' susceptibility to strain from patient movement necessitates compensation strategies.

Purpose of the Study:

• To design, manufacture, and characterize a novel needle-like probe housing four FBG sensors for temperature monitoring during LA.
• To differentiate between temperature-sensing and strain-sensing FBGs within the probe.
• To evaluate the probe's performance in a simulated clinical setting using ex vivo tissue.

Main Methods:

• A needle-like probe was fabricated, encapsulating three 1 mm FBG sensors (temperature) and one 10 mm FBG sensor (reference/strain).
• Encapsulation materials (thermal paste and epoxy resin) were chosen to optimize thermal exchange and strain sensitivity.
• Static calibration, step response analysis, and ex vivo swine liver experiments were conducted to characterize probe performance.

Main Results:

• The 1 mm FBGs exhibited a thermal sensitivity of 0.01 nm·°C⁻¹, while the reference FBG showed 0.02 nm·°C⁻¹.
• All FBGs demonstrated a response time on the order of 100 ms.
• Experiments on ex vivo liver tissue assessed measurement artifacts and probe feasibility in a quasi-clinical scenario.

Conclusions:

• The developed FBG-based needle probe is a viable tool for precise temperature monitoring during laser ablation.
• The probe design effectively mitigates strain-induced measurement errors, enhancing reliability in clinical applications.
• This technology holds promise for improving the safety and efficacy of laser ablation therapies.