Terahertz time-domain spectroscopy for non-invasive assessment of water content in biological samples.

We apply terahertz time-domain spectroscopy for the quantitative non-invasive assessment of the water content in biological samples, such as tree leaves and pork muscles. The developed experimental terahertz time-domain spectroscopy system operates both in transmission and reflection modes. The Landau-Looyenga-Lifshitz-based model is used for the calculation of the water concentration within the samples. The results of the water concentration measurements are compared with the results of the gravimetric measurements. The obtained results show that the water content in biological samples can be measured non-invasively, with a high accuracy, utilizing terahertz waves in transmission and reflection modes.