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Temperature knowledge may be beneficial to improve the outcomes of thermal treatments for tumor ablation. Among several thermometric methods, contactless approaches based on diagnostic imaging techniques are attractive for this field. Computed Tomography (CT) images are sensitive to temperature, so some groups of research are working to assess the feasibility of CT-based thermometry for monitoring the effects of thermal treatments. The aim of this study is to assess the feasibility of CT-thermometry during Microwave ablation (MWA) in ex vivo animal model. Healthy porcine livers were heated with two 2.45 GHz cooled-shaft MW antennas for four minutes at 65 W for each probe. Livers were scanned before heating and 16 times during the ablation (each 15 s). Liver temperature was measured in two points by two thermocouples. The relationship between the CT number (Hounsfield Unit, HU) and tissue temperature was investigated by using a linear regression analysis; thermal sensitivity of the CT number was estimated as the slope of the best fitting line. Results showed that CT number in liver tissue decreases during heating. The relationship between CT number and temperature is well described by a linear model (R2=0.91), and the thermal sensitivity is −0.52±0.02 HU∙°C-1. CT-based thermometry is feasible during MWA in ex vivo porcine livers. This technique is particularly attractive due to its non-invasiveness nature and can be used to monitor three-dimensional temperature distributions in heated tissues. Therefore, it may provide a powerful new tool during MWA or other thermal ablation procedures.

The importance of humidity control is spreading through a broad spectrum of applications, from food and pharmaceutical industries to biomedical and chemical fields. During the last decades, the growing interest in fiber Bragg gratings (FBG) led to new approaches and applications for the humidity measurement by means of the deposition of hygroscopic materials on gratings. The influence of the coating material and its features such us coating thickness (tk) and concentration (wt%) on static and dynamic metrological properties have been investigated in this paper. In this paper, four agar-coated FBG sensors for humidity measurements have been fabricated, and the influence of tk and wt% on the sensors’ sensitivity and response time has been experimentally assessed. Sensitivity increases with tk and wt%: for instance, at 1 wt% it was $0.0024\,\,\text {nm}\cdot {\%}^{\mathrm {-1}}$ and $0.0052\,\,\text {nm}\cdot {\%}^{\mathrm {-1}}$ for $\text {tk}=87\,\,\mu \text{m}$ and $\text {tk} = 212\,\,\mu \text{m}$ , respectively. Results showed that also the response time increased with tk and wt%: for instance, at 1 wt% it was 56.7 s and 107.6 s for $\text {tk} = 87\,\,\mu \text{m}$ and $\text {tk}=212\,\,\mu \text{m}$ , respectively.