Amazon.com description: Product Description: Contrast media are drugs by default. Had there been no default, there would be no need for a related pharmacology, and thus no need for this book. Radiographic contrast media (CM) are substances whose primary purpose is to enhance diagnostic information of medical imaging systems. The position of CM in pharmacology is unique. First, there is the unusual requirement of biological inertness. An ideal CM should be completely biologically inert, i.e., stable, not pharmacologically active, and efficiently and innocuously excretable. Because they fail to meet these requirements, CM must be considered drugs. The second unusual aspect of CM is that they are used in large quantities, their annual production being measured in tens of tons. It is not in spite of, but because of, the increased use of new radiographic systems, computed tomography, digital radiography, etc., that consumption is on the rise. And, it is not likely that the other emerging imaging modalities - NMR, ultrasonography, etc. - will displace radiographic CM soon; it is quite probable that these remarkable compounds will continue to play an active role in diagnostic imaging in the foreseeable future.