A fiber optic optoacoustic ultrasound sensor for photoacoustic endoscopy

Photoacoustic Endoscopy (PE) is a new imaging modality that can providehigh-resolution vascular imaging in vivo. Optoacoustic sensing (opticaldetection of ultrasound) is a good candidate for PE due to its enhancedsensitivity, wide bandwidth, and miniaturizability in comparison topiezoelectric, PVDF, and capacitive transducers. In this work we present thefabrication and testing of a fiber optic optoacoustic ultrasound sensor (fiberetalon), and we propose the development of a rectilinear ultrasound array for PEbased on this device. The design entails the bundling of several fiber etalonswhich, when combined with photoacoustic excitation, would yield a flexible andcompact, forward-viewing photoacoustic endoscope. To simulate the performance ofa bundled device, we have mechanically scanned a single fiber etalon to imagesimple photoacoustic targets. The results demonstrate the viability of using afiber optic-based photoacoustic endoscope to image optically absorptivestructures such as blood in vasculature. A potentially significant applicationof our device could be the monitoring of angiogenesis an early marker of tumorformation.