Photoacoustic Tomography

Optical imaging systems have a crucial role for studying brain function in animal models. However, traditional optical microscopy systems are inherently limited by their small volumetric coverage due to absorption and scattering of light. In contrast, photoacoustic imaging uses light to excite tissue, where a portion of the absorbed energy causes rapid heating, generating a wideband acoustic signal that is far less affected by scattering and absorption.

However, conventional ultrasound systems typically have resolutions in the millimeter range — significantly larger than the scale of neuronal structures. This limitation prevents current arrays from supporting high-resolution photoacoustic tomography (PAT). We are working on a high-resolution CMOS based ultrasound receiver which has been characterized using photoacoustic phantoms and in-vivo rodent models, achieving a lateral resolution of 30 µm and an axial resolution of 15 µm. The illustration diagram of the PAT chip is shown in the figure below.