Artifact-free imaging through a bone-like layer by using an ultrasonic-guided photoacoustic microscopy.

Reflection artifacts caused by a bone-like layer badly degrade the quality of photoacoustic images in many biomedical applications, e.g., in vivo brain imaging through the skull. We proposed an ultrasonic-guided photoacoustic microscopy (PAM) to remove the reflection artifacts. This system is developed from dual-mode microscopy, integrating a scanning acoustic microscopy with a conventional PAM. Based on similar propagation characteristics of a photoacoustic signal and ultrasonic echo in a bone-like layer, we employ the ultrasonic echo as a filter to remove the multiple reflected artifacts in photoacoustic signals and obtain artifact-free images. An experiment of imaging a phantom below a bone-like film is used to demonstrate the performance of this method. The results suggest that this method can achieve an artifact-free image of the phantom under the film successfully, whereas the conventional PAM fails to achieve clean images of the vessel-like absorbers. This study might improve the imaging quality of PAM in many biomedical applications.