Optoacoustic pressure amplitude is proportional to the thermoacoustic efficiency (Gruneisen parameter), which is proportional to temperature: p = ma F(z) G(T)
Therefore, when optical properties of tissues do not change under constant spatial distribution of the optical energy in tissues, brightness of voxels in optoacoustic images is proportional to temperature. Optoacoustic temperature image can be calibrated in absolute values using an image of a tube with colored water. At the temperature of 4OC, the image will abruptly change from positive to negative brightness (point of maximum water density).
Thus, optoacoustic temperature imaging is possible through a proprietary method described in our patent US10,123,707. Furthermore, due to the fact that dominating source of optoacoustic signals in live animals comes from red blood cells (RNC), and every organ of all live animals and humans contains certain concentration of RBCs, the method of temperature imaging is equally applicable to all live tissues.