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Transcranial ultrasound therapy has become a non-invasive method for treating neurological and psychiatric disorders, and studies have further demonstrated that multi-target transcranial ultrasound therapy is a better solution. At present, multi-target transcranial ultrasound therapy in small animals can only be achieved by the multi-transducer or phased array. However, multiple transducers may cause spatial interference, and the phased array system is complicated, expensive, and especially unsuitable for small animals. This study is the first to design and fabricate a miniature acoustic holography lens for multi-target transcranial ultrasound therapy in rats. The acoustic holographic lens, working at a frequency of 1.0 MHz, with a size of 10.08 mm × 10.08 mm and a pixel resolution of 0.72 mm, was designed, optimized, and fabricated. The dual-focus transcranial ultrasound generated based on the lens was measured; the full width at half maximum (FWHM) of the focal spots in y-direction were 2.15 and 2.27 mm, respectively, and in z-direction were 2.3 and 2.36 mm, respectively. The focal length was 5.4 mm, and the distance between the two focuses was 5.6 mm, close to the desired values of 5.4 mm and 6.0 mm, respectively. Finally, the multiple-target blood-brain barrier opening in rats' bilateral secondary visual cortex (mediolateral area, V2ML) was demonstrated using the transcranial ultrasound therapy system based on the lens. These results demonstrate the good performance of the multi-target transcranial ultrasound therapy system for small animals, including high spatial resolution, small size, and low cost.

Fiber Bragg gratings (FBGs) have being seen for a growing application in the field of structural health monitoring (SHM) because of their lightweight features. This letter introduces an adaptive SHM sensing system based on the ultrasonic guided wave (UGW) and FBG sensor technology. First, the capability of the proposed SHM sensing system used to detect UGW is demonstrated by the frequency detection of Rayleigh wave that is generated by the piezoelectric transducers with a function generator. Furthermore, a nanosecond pulse laser is utilized to generate Lamb wave on an aluminum plate, while the SHM sensing system is employed to detect the wave in a long distance. Finally, the SHM sensing system is used to locate the source of Rayleigh wave that is created by a pulsed laser. The experiment results show the proposed SHM sensing system is capable of localizing and monitoring the UGW by using four FBG cascaded on a loaded aluminum plate.