[Problem] To provide support during surgery by enabling an operator to more easily and accurately recognize the positional relationship between a treatment instrument and a blood vessel. [Solution] A photoacoustic imaging system (10, M) is provided with: a treatment instrument (M) for use in surgery a probe unit (70) having an electro-acoustic converter (3) that converts photoacoustic waves (U) into electrical signals an image generating means (2) that generates a three-dimensional photoacoustic image (P) on the basis of the electrical signals an information acquisition means (81, 82a, 82b, 83) that acquires information representing the positions and orientations in space of the treatment instrument (M) and the probe unit (70) relative to each other an image processing means (61) that, on the basis of the information representing the positions and orientations, superimposes a treatment instrument image (MI) indicating the position and orientation of the treatment instrument (M) a display unit (6) that displays the photoacoustic image (P) with the treatment instrument image (MI) superimposed thereon and a control means (4) that controls the aforementioned components so as to ensure that the photoacoustic image (P) with the treatment instrument image (MI) superimposed thereon is displayed in real time on the display unit (6).Lobjectif de la présente invention est dapporter une aide au cours dune opération chirurgicale en permettant à lopérateur de reconnaître plus facilement et plus précisément la relation positionnelle entre un instrument de traitement et un vaisseau sanguin. A cette fin, linvention concerne un système dimagerie photoacoustique (10, M) comprenant : un instrument de traitement (M) utilisé en chirurgie une unité de sonde (70) qui comporte un convertisseur électro-acoustique (3) convertissant des ondes photoacoustiques (U) en signaux électriques un moyen de génération dimage (2) qui génère une image photoacoustique en trois dimensions (P) sur la base de
