A medical imaging system and method is described. The system comprises: a microwave antenna array comprising a transmitting antenna and a plurality of receiving antennae, wherein the transmitting antenna is configured to transmit microwave signals so as to illuminate a body part of a patient and the receiving antennae are configured to receive the microwave signals following scattering within the body part； a marker configured to be applied to the surface of the skin of the body part and to scatter the microwave signals； a processor configured to process the scattered microwave signals and generate an image of the internal structure of the body part and the marker so as to identify a region of interest within the body part relative to the position of the marker.
