Polymer coated fiber Bragg grating thermometry for microwave hyperthermia

Area of Science:

• Biomedical Engineering
• Optical Sensing
• Medical Physics

Background:

• Accurate tissue temperature measurement is crucial for effective electromagnetic-induced hyperthermia (HT) therapy.
• Conventional thermometry methods, such as mechanically scanning probes, face limitations in speed and ease of use.
• Fiber Bragg Grating (FBG) technology offers potential for multipoint temperature sensing but requires improved stability for clinical use.

Purpose of the Study:

• To develop and evaluate a stable, high-speed fiber Bragg grating (FBG) based temperature sensing system for multipoint thermometry during microwave hyperthermia (HT).
• To compare the performance of the novel FBG system against conventional scanning probe thermometry in a simulated clinical setting.

Main Methods:

• A polymer-coated fiber Bragg grating (PFBG) probe with multiple sensing locations was developed.
• The PFBG probe and a conventional Bowman probe were used simultaneously to measure temperature distribution in a tissue-equivalent phantom during simulated microwave HT.
• System stability was assessed by measuring detection system drift over 10 hours, and response times were evaluated.

Main Results:

• The PFBG system demonstrated high temporal stability (better than 0.3°C drift) and rapid readout (2-second scans for ten points).
• Temperature profiles measured by the PFBG probe closely agreed with the Bowman probe, with a mean difference of 0.25°C.
• The PFBG system provided real-time, multipoint temperature measurements over a 5 cm length.

Conclusions:

• The developed fixed multipoint FBG thermometry system is a stable and effective alternative for distributed temperature measurements during clinical microwave HT.
• This technology offers advantages in ease of use and speed compared to traditional scanning or bundled single-point probes.