Interpolation is a mathematical process used to smooth, enlarge or average images that are being displayed with more pixels than that for which they were originally reconstructed.

The first-generation contrast agents were all ionic monomers, consisting of a tri-iodinated benzene ring with 2 organic side chains and a carboxyl group. Diatrizoate or iothalamate are common iodinated anions, conjugated with a cation, sodium or meglumine. The ionization at the carboxyl-cation bond makes the agent water soluble.
Ionic monomers have the highest osmolality (high-osmolar contrast media (HOCM) possess an osmolality seven to eight times higher than plasma) of the different groups of contrast agents (CM ratio=1.5) and the lowest viscosity. The osmolality in solutions of ionic monomers ranges from 600 to 2100 mOsm/kg (human plasma = 290 mOsm/kg). These high osmolality is related to some of the adverse reactions. HOCM's have been widely replaced by newer contrast agents with improved tolerability and safety profiles.
Examples of HOCM's are Renografin®-60, Hypaque 76, Hypaque Meglumine, Hypaque Sodium and Conray®.

See also Ionic Contrast Agents.

Usually, magnification is the enlargement of an area by interpolation after the reconstruction of an image. Magnification does not provide more information, but allows a better view of certain object details. A zoom reconstruction is based on the raw data of the scan. Magnification software enlarges an image by mapping one pixel onto an n x n array of screen pixels (pixel stretching).
Other types of magnification include electron-optical, geometric, the product of geometric and the electron-optical magnification and enlargement by imaging procedures.
Electron-optical magnification is the ratio of the dimension of the detector input image and the size of the image on the screen. This ratio is determined by all electronic and optical imaging processes of the image chain, provided that one camera pixel is mapped onto accurately one monitor pixel.
Geometric magnification occurs in x-ray images when the focal spot is theoretically assumed to be a point and not an area. For nanofocus and microfocus radiographic systems, the focus-to-detector (film) distance and the focus-to-object (film) distance defines the geometric magnification.
The total magnification is the product of the electron-optical and geometric magnification. Possible magnifications are up to a factor of 26,000.
Magnification procedures in medical imaging are usually produced by extended distance between the subject and the image receptor.

Nuclear reaction in which a neutron enters the nucleus and a proton is emitted.

Nuclear reaction in which a proton enters the nucleus and a neutron is emitted.