主 讲 人：Sio Hang Pun
主 办 方：物理与信息工程学院
Monolithic Multi-band Capacitive Micro-machined Ultrasound Transducers (CMUTs) for Photoacoustic Computed Tomography (PACT)
主讲人：Sio Hang Pun, 副教授, 澳门大学模拟与混合信号超大规模集成电路国家重点实验室
摘要：Among the biomedical imaging modalities, photoacoustic computed tomography (PACT) imaging is one of the fast growing techniques in recent years. In designing the PACT imaging system, a finite bandwidth transducer is one of the limited factors for the overall performance. As the target size is inversely proportional to the dominant frequency components of the generated photoacoustic (PA) signal, a broad bandwidth transducer is desired for different scales imaging. Among various ultrasonic transducers for detection of the PA signal, the use of CMUT as a PA signal detector has several advantages, such as, wider bandwidth and different sizes can be easily fabricated by using the silicon micromachining technology, better matching of acoustic impedance to the human body, easier to form ring type/two dimensional arrays, and facile integration with front-end electronics.
In this talk, we are going to introduce a monolithic multi-band CMUT array for the reception of the wide band PA signals so as to provide high resolution images with high frequency CMUT arrays and present the high signal-to-noise-ratio major structure with low frequency CMUT arrays. To demonstrate its performance, a phantom experiment was conducted to show and evaluate the various qualities of multi-resolution images. In addition, an in vivo mouse model experiment was also carried out for revealing the multi-scale photoacoustic imaging capability with the multi-band CMUTs on biological tissues. From the obtained results, the images from different CMUT arrays could show the structures of the mouse brain in different scales. In addition, the images from the high frequency CMUT arrays were able to reveal the major blood vasculatures, whereas, the images from low frequency CMUT arrays showed the gross macroscopic anatomy of the brain with higher contrast.