Optoacoustic supercontrast for early cancer detection

Thermal mechanism is fundamental for the generation of ultrasonic waves in a course of absorption of laser radiation. Its efficiency is relatively tow, but increases significantly with temperature (thermal non-linearity). If the phase transition of the irradiated medium occur, the efficiency may exceed its linear regime value several orders of magnitude. The idea of optoacoustic supercontrast for early cancer detection is based on this fact. We performed feasibility studies and describe requirements to and properties of the optoacoustic supercontrast agent based on nanoscopic particles. The results of the preliminary experiments with the metal and carbon nanoparticles as optoacoustic supercontrast are presented. Theoretical estimations show the possibility to enhance the efficiency of optoacoustic generation up to three orders of magnitude under irradiation conditions of laser optoacoustic imaging in the depth of human tissue.