Virtual-detector synthetic aperture focusing technique with application in in vivo photoacoustic microscopy

Meng-Lin Li; Hao F. Zhang; Konstantin Maslov; George Stoica; Lihong V. Wang

doi:10.1117/12.645115

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6 March 2006 Virtual-detector synthetic aperture focusing technique with application in in vivo photoacoustic microscopy

Meng-Lin Li, Hao F. Zhang, Konstantin Maslov, George Stoica, Lihong V. Wang

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Proceedings Volume 6086, Photons Plus Ultrasound: Imaging and Sensing 2006: The Seventh Conference on Biomedical Thermoacoustics, Optoacoustics, and Acousto-optics; 60861F (2006) https://doi.org/10.1117/12.645115
Event: SPIE BiOS, 2006, San Jose, California, United States

Abstract

In this study, we introduce a synthetic aperture focusing technique which employs a virtual detector concept, combined with coherence weighting, to extend the depth of focus for an in-vivo photoacoustic microscopy system. This technique treats the transducer's focal point as a virtual point detector of photoacoustic signals, delays adjacent scan lines relative to the virtual detector, and then sums the delayed signals to achieve focusing in the out-of-focus region. In addition, a coherence factor among the delayed signals for each synthesized imaging point is used as a weighting factor to further improve the focusing quality. Images of an Intralipid phantom containing a carbon fiber show how this technique improves the -6 dB lateral resolution from 49-379 μm to 46-53 μm and increases the SNR by 0-29 dB, depending on the distance from the ultrasonic focal point. In vivo experiments show that this technique also provides a clearer tumorassociated angiogenesis in the mouse's scalp. The extended depth of focus for the photoacoustic microscopy system enables 3D reconstruction of the vascular network for the study of tumor angiogenesis.

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Meng-Lin Li, Hao F. Zhang, Konstantin Maslov, George Stoica, and Lihong V. Wang "Virtual-detector synthetic aperture focusing technique with application in in vivo photoacoustic microscopy", Proc. SPIE 6086, Photons Plus Ultrasound: Imaging and Sensing 2006: The Seventh Conference on Biomedical Thermoacoustics, Optoacoustics, and Acousto-optics, 60861F (6 March 2006); https://doi.org/10.1117/12.645115

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