Interdigitated annular CMUT arrays for ultrasound assisted delivery of fluorescent contrast agents

Detection of early stage cancer is critical to successful treatment. Molecular imaging contrast agents offer great promise for early stage cancer detection. For improved image quality and diagnostics there is a need to improve the delivery, activation, and uptake of molecular imaging contrast agents. Low intensity focused ultrasound is one option to improve the delivery of molecular imaging agents. Here we investigate a circularly symmetric interdigitated capacitive micromachined ultrasonic transducer for improved delivery of fluorescent contrast agents to be imaged by a miniature dual axis confocal microscope. In order to apply ultrasound energy in the field of view of the optical microscope interface waves must be exploited. The device clearly focuses the ultrasound energy on the surface and at the center of the device. Overlapping the field of view of the optical microscope is required for improved in vivo imaging. Reasonable intensities of about 145 mW/cm² have been demonstrated for enhanced delivery of the contrast agents.