Abstract: “Herein disclosed is an ex vivo method of identifying a state of a tumor margin in a sample. The method comprises operating a system to generate an ultrasound image and a photoacoustic image, wherein the system comprises: a probe configured to deliver a pulsed laser from a laser source to a sample, wherein the laser source is operable to generate the pulsed laser; arrays coupled to the probe, wherein one of the arrays comprises transducing elements arranged thereon which are operable to transmit and collect ultrasound signals, and wherein one of the arrays comprises transducing elements arranged thereon which are operable to collect photoacoustic signals; and a data acquisition module which converts the ultrasound signals and the photoacoustic signals into the ultrasound image and the photoacoustic image, respectively.