An apparatus for holding an imaging subject, such as a whole animal, within a photoacoustic computed tomography system with dry acoustic coupling is disclosed. The apparatus includes a dry acoustic coupler with a tubular elastic membrane made of an optically and acoustically transmissive material. The tubular elastic membrane defines a lumen and at least one lumen opening proximate to a membrane end. In use, the lumen of the tubular elastic membrane is positioned within a coupling fluid contained within a tank of the photoacoustic computed tomography system. The apparatus enables contact-free acoustic coupling of the imaging subject with the coupling fluid during PA imaging. The tank may be optionally pressurized to enhance stabilization of the imaging subject within the coupling fluid.
