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Transcranial photoacoustic computed tomography based on a layered back-projection method

2020; Elsevier BV; Volume: 20; Linguagem: Inglês

10.1016/j.pacs.2020.100213

2213-5979

Shuai Na, Xiaoyun Yuan, Li Lin, Julio Isla, David C. Garrett, Lihong V. Wang,

Optical Imaging and Spectroscopy Techniques

A major challenge of transcranial human brain photoacoustic computed tomography (PACT) is correcting for the acoustic aberration induced by the skull. Here, we present a modified universal back-projection (UBP) method, termed layered UBP (L-UBP), that can de-aberrate the transcranial PA signals by accommodating the skull heterogeneity into conventional UBP. In L-UBP, the acoustic medium is divided into multiple layers: the acoustic coupling fluid layer between the skull and detectors, the skull layer, and the brain tissue layer, which are assigned different acoustic properties. The transmission coefficients and wave conversion are considered at the fluid-skull and skull-tissue interfaces. Simulations of transcranial PACT using L-UBP were conducted to validate the method. Ex vivo experiments with a newly developed three-dimensional PACT system with 1-MHz center frequency demonstrated that L-UBP can substantially improve the image quality compared to conventional UBP.