Temperature monitoring by fiber bragg gratings during microwave ablation of Ex vivo organs for heat sink effect assessment

Among the existing thermal ablation techniques, microwave ablation (MWA) is gaining momentum due to its great potentialities in the treatment of several organs. MWA effectiveness is influenced by several factors, such as ablation system design and patients' anatomical characteristics. The presence of large blood vessel in the proximity of tumor masses dissipates heat by convection (phenomenon known in the literature as heat sink effect). The potential consequence is the risk of incomplete tumor ablation. In this study, we experimentally investigated such phenomenon in ex vivo swine liver during MWA. The blood vessel was mimicked through a silicone tube inserted within the organ. To evaluate the influence of the heat sink effect on MWA, we measured the tissue temperature by fiber Bragg grating sensors (FBGs) in two different configurations (i.e., with and without blood vessel nearby the MW applicator). The notable differences in terms of temperature recorded in the two different scenarios demonstrated the cooling effect caused by blood vessel.