Coulomb is the SI unit of electric charge. One coulomb is the amount of charge accumulated in one second by a current of one ampere.
The charge of a proton is 1.6 x 10^-19 coulombs. The charge of an electron is - 1.6 x 10^-19 coulombs. An atomic particle has a charge which is an integral multiple of 1.6 x 10^-19 coulombs.

(Computed tomography number) The CT number is a selectable scan factor based on the Hounsfield scale. Each elemental region of the CT image (pixel) is expressed in terms of Hounsfield units (HU) corresponding to the x-ray attenuation (or tissue density).
CT numbers are displayed as gray-scale pixels on the viewing monitor. White represents pixels with higher CT numbers (bone). Varying shades of gray are assigned to intermediate CT numbers e.g., soft tissues, fluid and fat. Black represents regions with lower CT numbers like lungs and air-filled organs.

(C, c, Ci) Curie is an obsolete unit of radioactivity; superseded by the SI unit becquerel.
1 curie is 3.70 x10¹⁰ disintegrations per second or 37,000 MBq. Formerly it was defined as the radiation emitted by 1 g of radium.
The curie is originated on Marie (1867-1934) and Pierre (1859-1906) Curie, (French chemists and physicists and Nobel laureates).

See Becquerel.

(dB) A customary logarithmic measure most commonly used (in various ways) for measuring sound. Decibel is a way to express the ratio of two sound intensities: dB=10log10I1/I2 being I1 the reference. If one sound is 1 bel (10 decibel) 'louder' than another, this means the louder sound is 10 times louder than the fainter one. A difference of 20 decibel corresponds to an increase of 10 x 10 or 100 times in intensity.
The intensity of ultrasound is measured in db/cm and decreases during the propagation.
For sound pressure (the pressure exerted by the sound waves) 0 decibel equals 20 micropascal (µPa), and for ultrasonic power 0 decibel sometimes equals 1 picowatt.
See also Phon, Pascal, Logarithms, Proportionality Constant, Watt, Diagnostic Imaging.

(D) The electric flux density is a vector equal to the product of the electric field strength and the permittivity. The unit is coulomb per square meter (C/m²). The total electric flux passing through a closed surface is equal to the total charge enclosed by the surface.

(P) The electric polarization refers to the separation of charges in a material to form electric dipoles, or the alignment of existing electric dipoles in matter when an electric field is applied. The unit of electric polarization is dipole moment per cubic meter or coulomb per square meter(C/m²).