The advent of mini-invasive surgical techniques to treat tumours has increased the number of successful recoveries, while minimizing the patient discomfort. These techniques usually rely on the generation of a localized thermal gradient, either heating (High Intensity Focused Ultrasound, Radiofrequency Ablation, Microwave Ablation, and Laser Ablation), or cooling (Cryoablation) the tissue at cytotoxic levels. The aim of this Master's Thesis has been the study of novel optical fibre temperature sensors for the real-time monitoring of percutaneous Laser Ablation (LA) treatments. Fibre Optic sensors are particularly attractive for LA because they can be integrated into the applicator, do not introduce artefact due to interactions with the laser beam; moreover, being all non-conductive, they cannot cause electrocution and can be used under the Nuclear Magnetic Resonance procedures employed to position the applicator and monitor the treated tissue evolution.