201 / 2024-07-11 14:43:04

Noninvasive high-resolution deep-brain photoacoustic imaging with fiber-laser ultrasound transducer

focused fiber-laser ultrasound transducer,deep brain imaging,photoacoustic tomography

Noninvasive high-resolution deep brain imaging is essential to fundamental cognitive process study and neuroprotective drugs development. Although optical microscopes can resolve fine biological structures with good contrast without the exposure to ionizing radiation or strong magnetic field, the optical scattering limits the penetration depth and hinders its capability for deep-brain imaging. Here, in vivo high-resolution imaging of the whole mouse brain is demonstrated by using photoacoustic computed tomography system with a focused fiber-laser ultrasound transducer. By leveraging the high flexibility and low bending loss of the optical fiber, a rationally-designed focused fiber laser cavity exhibits a low detection limit down to 5.4 Pa and can effectively detect biological ultrasound signals with the frequency up to 20 MHz. Thus, it enables mouse brain imaging with a penetration larger than 7 mm and a nearly isotropic spatial resolution of ~130 μm. In vivo imaging of the quantification of the blood oxygenation status in mouse brain is also showcased to demonstrate its capability for potential biomedical and clinic applications. With high spatial resolution and large tissue penetration, the system may provide a high-performance imaging solution for biomedical research and preclinical/clinical diagnosis.