This Small Business Innovation Research (SBIR) Phase I project focuses on the development of a new photoacoustic imaging system that cascades a miniature infrared light source behind an infrared-transparent capacitive micromachined transducer (CMUT) array, and illuminates the image target through the CMUT array. The unique features of this illumination-through-transducer design are in that 1) there is no need for external alignment mechanisms between the transducer and the light source during image acquisition, 2) depth at which the tissue can be imaged is increased to 10 cm, and 3) overall size of the integrated imager head is significantly reduced with the cascaded structure. Key objectives of this research include design, modeling, fabrication, packaging and testing of of a Capacitive Micromachined Ultrasonic Transducer (CMUT) array that is transparent to near infrared (NIR) illumination. We anticipate to successfully demonstrate the functionality and the feasibility of integration of this CMUT array in a cascaded light-source-to-CMUT PAI system. This system will be used for breast and other type of cancers screening. The proposed PAI system will be an enabling technology platform for medical imaging, diagnosis and monitoring. The broader impact/commercial potential of this project lies in that the technology developed here can be applied outside of the proposed photo acoustic imaging applications in clinical settings. Initially, this technology will leverage some of the existing hardware profile of the traditional ultrasound systems, to result in a safe, portable, low cost medical imaging device for screening and early detection of breast and other cancers. While optical microscopy continues to evolve through integration of optics with microfluidics for diagnostic applications, it still has limitations such as lack of portability and high cost due to complex and expensive optical components. With proposed technology, multiple detection and imaging modalities can be integrated for on-chip detection of infectious disease, as an alternative to optical microscopy. Moreover, the proposed system can be used as a light-to-mechanical and/or mechanical-to-light energy transducer in combination with microfluidics, to enable a range of point-of-care diagnostics and monitoring applications. The proposed technology can be combined with other emerging technology platforms including optofluidics and acustofluidics, to enable more functionality in smaller devices and at lower cost, for mobile-based clinical microscopy in a range of global healthcare applications
