Hand-Held Optoacoustic System for the Localization of Blood Vessels

The ability to rapidly locate blood vessels in patients is important in many clinical applications, e.g., in bypass surgery. Optical techniques, including visual inspection, generally suffer from a reduced performance at depths below 1 mm, while ultrasound and optoacoustic tomography are better suited to a typical depth on the scale of 1 cm and require an additional spacer between the tissue and transducer in order to image the superficial structures at the focus plane. In this work, we have developed a portable hand-held optoacoustic probe, designed for localizing blood vessels from the contact point down to a depth of 1 cm, without the use of a spacer. The probe employs a flat lens-free ultrasound array, enabling a largely depth-independent response down to a depth of 1 cm, at the expense of low elevational resolution.

The system’s performance has been experimentally characterized using tissue-mimicking phantom in terms of sensitivity, resolution, and visual appearance of cylindrical structure that emulate blood vessels. The work culminates in an in vivo study in which the system is used to image the coronary arteries of a sheep, demonstrating higher contrast-to-background ratio than pulse-echo ultrasound.

M.Sc. student under the supervision of Professor Amir Rosenthal.