Hybrid Spherical Array for clinical optoacoustic ultrasound (OPUS) imaging

Optoacoustic tomography (OAT) has made major advances towards clinical diagnostics in recent years. One major obstacle inhibiting the establishment of this non-invasive non-ionizing technique as a routine diagnostic device is the unfamiliarity of clinicians to OAT images. Several works have already been dedicated to combining Optoacoustic and Ultrasound imaging (OPUS). However, thus far, dual mode 1D arrays have mostly been employed. Not only are the resulting 2D OAT images subject to out-of-plane artefacts, but as the transducer specifications are typically optimized for OA imaging, the US image quality tended to be comparatively poor. Here, we present a concave spherical detector with dedicated OAT and US transducer, where the optimized transducer design boasts excellent image resolution for both modalities. Real-time OPUS acquisitions were performed on healthy human subjects in several regions, including the neck and forearm. 3D OAT volumes were supplemented with a 2D US cross-sections, enabling the complementary identification of key anatomical structures. The contextual structural information offered by US allows for the further exploitation of the rich OA molecular contrast. This showcase demonstration is an important step towards establishing OAT as a clinical point-of-care device.