A gas formulation that is intended to be inhaled by the patient in order to temporarily enable or enhance the ability to differentially visualize targeted body structures on images generated by various diagnostic x-ray systems, e.g., computed tomography (CT) or fluoroscopy. It is used in x-ray imaging applications and intended to increase the ability to differentiate between normal and pathological conditions when analysing or interpreting medical images and information generated using a diagnostic x-ray system. After application, this device cannot be reused.