Instrument for acquiring co-registered orthogonal fluorescence and photoacoustic volumetric projections of tissue and methods of its use

Abstract

Disclosed are instruments and methods for acquiring co-registered orthogonal fluorescence and photoacoustic volumetric projections of an interrogated object. In an embodiment, an instrument includes a rotary mechanism configured to rotate an interrogated object relative to an array of photoacoustic transducers and an optical detector. An optical excitation unit is configured to irradiate the interrogated object with pulses of light, inducing both fluorescence and photoacoustic responses inside the interrogated object at each of a plurality of rotational positions. The array of photoacoustic transducers includes unfocused elements arranged in a pattern along an axis of rotation, the elements configured to detect photoacoustic signals generated inside the volume of the interrogated object. The optical detector is arranged opposite to the array of photoacoustic transducers with respect to the axis of rotation and is configured to register sources of fluorescence excited inside the interrogated object. Each of the optical excitation axes form with each of the optical detection axes, and with each of the photoacoustic detection axes, angles that are between 60° and 90° so as to enable acquisition of co-registered orthogonal fluorescence and photoacoustic volumetric projections of the interrogated object.