Improving photoacoustic-imaging axial positioning accuracy and signal-to-noise ratio using acoustic echo effect

Abstract We have developed a method to improve the performance of photoacoustic (PA) imaging technique by applying the acoustic echo effect. By superimposing the main and echo ultrasound signals, the axial positioning accuracy of a PA imaging system could be improved by 100% and the signal-to-noise ratio (SNR) could be enhanced by ∼2.8 dB experimentally. Using a multiwall carbon nanotubes composite structure as a sample, the occurrence conditions and properties of the echo signals were discussed. Theoretically, the SNR could be increased within a working distance of ∼3.9 mm when water is used as the medium. Moreover, we found that PA images of red blood cells could also be enhanced by this method.