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 an imaging tank filled with a liquid coupling medium. An object positioning mechanism is configured to position the interrogated object inside the coupling medium and to rotate the interrogated object. An optical excitation unit that is fixed with respect to the tank is configured to induce both fluorescence and photoacoustic responses inside the interrogated object using the same optical excitation spectrum and the same irradiation pattern at the surface of the interrogated object. An array of unfocused photoacoustic transducers is fixed with respect to the tank, and each element of the array is configured to detect photoacoustic signals generated inside the interrogated object. The array is arranged such that a plane connecting the rotation axis and a central portion of the array cuts through the interrogated object separating the two sides irradiated by the optical excitation unit. An optical detector that is fixed with respect to the tank is configured to register planar projections of sources of fluorescence generated inside the object. A data acquisition unit is configured to synchronize acquisition of photoacoustic data, acquisition of fluorescence data, optical excitation, and rotational position of the interrogated object.