Fiber Bragg Grating Based Temperature Sensor for Tissue Thermometry during Hyperthermia: A Simulation Study

Fiber optic point sensors employing phosphorescence technique are widely used for tissue temperature monitoring during radiofrequency and microwave hyperthermia treatment of cancer
$(40^{\circ}\mathrm{C}-45^{\circ}\mathrm{C})$
due to it low interference with the radiated electromagnetic field. These sensors do not support distributed sensing of the tissue temperature. This paper investigates the utility of Fiber Bragg Grating (FBG) sensor as an alternate to phosphorescence - based fiber optic point sensor for temperature measurement during microwave hyperthermia treatment. As the FBG sensor is susceptible to strain and temperature changes, the shift in the Bragg wavelength is studied for a static applicator load acting on the FBG point sensor over a clinical temperature range
$(25^{\circ}\mathrm{C}-55^{\circ}\mathrm{C})$
. The simulations are performed in MATLAB for single mode FBG sensor at 1550 nm. The shift in Bragg wavelength is quantified for clinical load and temperature conditions to study the feasibility of FBG point sensor for tissue thermometry during microwave hyperthermia treatment.