1LM-15 : Light-induced resonance-based frequency-selective amplification for combined photoacoustic-ultrasound imaging

Photoacoustic imaging is an emerging biomedical imaging modality which offers high spatial resolution and visualization at much deeper than the depth achieved by other optical imaging modalities. However, the sensitivity of photoacoustic imaging is quite limited due to background signals produced from endogenous optical absorbers. To overcome this technical hurdle, exogenous photoacoustic contrast agents have been employed in efforts to improve sensitivity. However, photoacoustic signal usually contains a broad range of frequency components, whereas the ultrasound transducer is only capable of receiving signals within a certain frequency range. In this study, we show that the gas-cored structure of a porphyrin-phospholipid microbubble (p-MB) can act as a resonance frequency-selective amplifier for photoacoustic signals produced from the embedded porphyrin, thus improving the efficiency of the signal reception and allowing for more sensitive photoacoustic imaging.