Fibre probe for tumour laser thermotherapy with integrated temperature measuring capabilities

The development and preliminary characterisation of a novel fibre probe for laser thermotherapy of solid tumours are presented. The probe introduces two innovative features: the tailoring of the laser irradiation pattern to adapt it also for larger tumour applications, and the all-optical real time evaluation of the induced temperature increase. These features are simultaneously obtained by integrating in a single capillary tube a laser delivery fibre with properly micro-structured tip surface together with some fibre Bragg gratings. Preliminary validation examples in human liver phantoms have demonstrated the viability of the proposed approach for the development of a whole set of new probes for laser ablation in medical applications

Experimental qualification of fiber bragg grating sensors for temperature monitoring in laser ablation

The paper discusses the main issues related to the usage of Fiber Bragg Grating as temperature sensors when they are employed to monitor percutaneous laser ablation of tumors. After a description of the main problems related to this specific application, two different setups for the characterization and the qualification of these sensors are described and preliminary results are presented

Temperature Monitoring with Fiber Bragg Grating Sensors in Non-Uniform Conditions

Fiber optics is the elective technology for sensing temperatures in harsh environments. Among the possible exploitable working principles, fiber Bragg gratings are the most widespread implementation for their excellent balance between system complexity and performance. However, despite they are well known and established, so far metrological investigations have been limited to cases in which the sensor is used in uniform temperature conditions. This paper analyzes the response of commercial fiber Bragg gratings employed as temperature sensors in applications that imply large temperature gradients, such as in laser based thermal treatments of solid tumors. A theoretical model of the sensor is implemented first and then used to evaluate its response in non-uniform temperature distributions. The model results are experimentally validated by means of a liver phantom and comparisons between different grating configurations, such as single or multiplexed with different lengths, are made

Evaluation of Temperature Measurement Errors due to FBG Sensors During Laser Ablation of Ex-Vivo Porcine Liver

The paper presents a theoretical evaluation of the systematic errors due to the thermal properties of the fiber sensors employed to monitor the temperature increase during liver laser ablation procedures. The opto-thermal finite element model of the laser induced temperature distribution in an exvivo liver is introduced first; then, different types of sensor embodiments are considered and their effects on the temperature distribution evaluated. Both electrical sensors with metallic wires and fiber optic sensors have been analyzed. Temperature errors up to 3 ◦C are expected when a fiber sensor embedded in a glass capillary is employed