Patent ID: 8366671

Claim:
A contrast media injector system comprising: a syringe ram engageable with a plunger of a syringe when mounted to said injector system; a drive mechanism coupled with the syringe ram and configured to position the syringe ram at different locations; a reflective surface; and an optical sensor which transmits radiation towards the reflective surface and radiation is reflected therefrom back to the optical sensor, wherein a path of the radiation traveling between the reflective surface and the optical sensor is parallel to a dimension in which the syringe ram is moved by the drive mechanism, only one of the optical sensor and the reflective surface being movable along with the syringe ram within the injector system such that the other of the optical sensor and the reflective surface does not move along with the syringe ram, wherein the reflective surface and the optical sensor are incorporated by the injector system such that movement of the syringe ram by the drive mechanism changes a spacing between the reflective surface and the optical sensor in a dimension that is parallel to the dimension in which the syringe ram is moved by the drive mechanism, and wherein the distance traveled by the radiation between the reflective surface and the optical sensor, in the dimension that is parallel to the dimension in which the syringe ram is moved by the drive mechanism, is a measure of an absolute position of the syringe ram at the different locations within the injector system.