Temperature Assessment During Radio Frequency Ablation in Ex Vivo Long Bone by Fiber Bragg Grating Sensors

Thermal ablation treatments (TATs) are promising alternatives to traditional surgery for bone cancer eradication. Among several TATs, radio frequency ablation (RFA) has gained considerable ground in treating bone cancer. Therefore, tracking temperature is paramount in ensuring complete tumor destruction without injuring adjacent structures. Despite the widespread use of RFA for bone tumors, investigations on temperature distribution during this procedure are so far lacking. To date, only thermocouples and thermistors have been proposed to measure temperature during RFA in bone. However, these sensors are intended to measure temperature at a single point without information about heat propagation into the tissue during ablation. Within this context, fiber Bragg grating sensors (FBGs) can play a crucial role since their multiplexing capability enables temperature measurement at several locations. This work seeks to fill this gap by providing new insights into RFA effects on bone tissue. Experiments are performed on ex vivo porcine femurs. During trials, two commercial stainless-steel needles equipped with an optical fiber housing six FBGs each were employed to record temperature over time. This solution allowed for monitoring temperature in 12 tissue points inside the bone at a fixed distance from the RF probe, thus gaining information about the thermal distribution in a large tissue area over time. This study paves the way for a more in-depth understanding of the efficacy of RFA in bone tissue, thus providing a powerful method for temperature monitoring, potentially enhancing the treatment outcomes.