The goal of this proposal is to develop a tissue hydration imaging system based on THz and NIR illumination to spatially and temporally map the hydration state of burn wounds and correlate these measurements with burn severity. Burn severity is typically assessed with visual and tactile feedback from the surgeon and diagnostic accuracy varies widely based on the clinical presentation and the surgeon's experience. In a large number of burn centers complementary assessments are made by burn wound blood perfusion measured with Laser Doppler Imaging (LDI) and vital dye based systems. These techniques are based on blood perfusion and do not provide immediate assessment of burn wound severity due to the evolving response to the burn injury. This limitation prevents the use of these techniques during the first 48 hours following injury leading to a delay in optimal management. Preliminary in vivo results obtained by our group in rats suggest that hydration imaging acquired with THz and NIR illumination may provide information to non-invasively assess burn severity within the first few hours of injury. This information may allow the burn surgeon to rapidly differentiate between partial and full thickness injury. THz and NIR illumination are eye safe, have very low photon energy, and are extremely sensitive to hydration changes secondary to edema which is part of the tissue response to thermal injury. This study will begin with the construction of a scanned beam, THz imaging system capable of non-contact, imaging of a 10 cm x 10 cm square area in less than 30 seconds. A companion NIR imaging system tuned to the peak absorption wavelength of water will be developed and used for comparison. We will also provide additional information regarding wound hydration. Year 2 will encompass extensive animal work in rats (N = 20) and the capability of these imaging systems for burn severity diagnosis will be evaluated against clinical and histopathological diagnosis.