A system for detecting post-operative retained foreign bodies has a data storage unit adapted to receive and store a reference image of a surgical object, and a data processor in communication with the data storage unit. The data processor is configured to receive an image of an internal region of a patient and to receive the reference image from the data storage unit, and the data processor is configured to perform operations based on an algorithm to compare the reference image to at least a portion of the image of the internal region of the patient and determine whether a retained foreign body is present in the patient.