contrast agent
(2) For purposes of this subsection: (A) The term “contrast agent” means an article that is intended for use in conjunction with a medical imaging device, and— (i) is a diagnostic radiopharmaceutical, as defined in sections 315.2 and 601.31 of title 21, Code of Federal Regulations (or any successor regulations); or (ii) is a diagnostic agent that improves the visualization of structure or function within the body by increasing the relative difference in signal intensity within the target tissue, structure, or fluid. (B) The term “radioactive drug” has the meaning given such term in section 310.3 (n) of title 21, Code of Federal Regulations (or any successor regulations), except that such term does not include— (i) an implant or article similar to an implant; (ii) an article that applies radiation from outside of the body; or (iii) the radiation source of an article described in clause (i) or (ii). (C) The term “OTC monograph drug” has the meaning given such term in section 379j–71 of this title .