Effect of Amplifier Gain to Photoacoustic SNR (Signal to Noise Ratio) in an LED-base Photoacoustic Imaging System

Abstract

Functional diagnosis possibility of photoacoustic imaging has been attracted much attention especially in clinical field. Among them, a system using compact and low priced LED light source which visualize real time image has appeared. Compared to solid state laser, the pulse energy of LED was extremely small, so it had been thought that imaging was so difficult, but by adding pre-amplifier, real time photoacoustic imaging became possible. However the SNR and the amplifier gain needed for making real time imaging possible are not clear. In this work, we have clarified using the phantom and human fingers that SNR > 4 and amplifier gain > 80 dB were found to be needed and why making image without a pre-amplifier had been difficult.