Development of a photoacoustic handheld probe using 2-axis MEMS scanner

Optical resolution photoacoustic tomography (OR-PAM) is a non-invasive imaging method that uses endogenous contrast agents in the body, such as hemoglobin in the blood. OR-PAM has a resolution equivalent to a microscope, and has high optical contrast. OR-PAM has been made to expand the application to the medical field by increasing the speed of imaging and minimizing the size of the system. In this research, we accomplished these two specifications by using MEMS technology to integrate a fast scan functionality into a handheld probe. Using MEMS technology, beam guides, ultrasound guidance, and mechanical scanning subsystems were integrated into a single small probe. The measured lateral resolution is 16 mu m, and the measured B-scan and volume imaging rate are 35 and 0.2 Hz to obtain a photoacoustic (PA) image with 200 and 700 pixels. We imaged a variety of phantom and in vivo samples such as carbon fibers, mouse ears, eyes, and brains.