Temperature distribution monitoring in tissue undergoing Laser Ablation (LA) could be beneficial for improving treatment outcomes. Among several thermometric techniques employed in LA, Fiber Bragg Grating (FBG) sensors show valuable characteristics, although their sensitivity to strain entails measurement error for patient respiratory movements. Our work describes a solution to overcome this issue by housing an FBG in a surgical needle. The metrological properties of the two probes and of non-encapsulated FBG were assessed in terms of thermal sensitivity and response time. The error due to the strain caused by liver movements, simulating a typical respiratory pattern, was assessed on the two probes, and compared to the response of non-encapsulated FBG. The metallic needle entails a measurement error, called artifact, due to direct absorption of the laser radiation. The analysis of the artifact was performed by employing the probes for temperature monitoring on liver undergoing LA. Experiments were performed at two laser powers (i.e., 2 W and 4 W), and at 9 distances between the probes and the laser applicator. Results show that the artifact decreases with the distance and increases with power.
A needlelike probe for temperature monitoring during laser ablation based on FBG: manufacturing and characterization
Massaroni C;Silvestri S;Schena E
2015-01-01
Abstract
Temperature distribution monitoring in tissue undergoing Laser Ablation (LA) could be beneficial for improving treatment outcomes. Among several thermometric techniques employed in LA, Fiber Bragg Grating (FBG) sensors show valuable characteristics, although their sensitivity to strain entails measurement error for patient respiratory movements. Our work describes a solution to overcome this issue by housing an FBG in a surgical needle. The metrological properties of the two probes and of non-encapsulated FBG were assessed in terms of thermal sensitivity and response time. The error due to the strain caused by liver movements, simulating a typical respiratory pattern, was assessed on the two probes, and compared to the response of non-encapsulated FBG. The metallic needle entails a measurement error, called artifact, due to direct absorption of the laser radiation. The analysis of the artifact was performed by employing the probes for temperature monitoring on liver undergoing LA. Experiments were performed at two laser powers (i.e., 2 W and 4 W), and at 9 distances between the probes and the laser applicator. Results show that the artifact decreases with the distance and increases with power.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.