primary and widely in use computed tomography (ct) dose descriptor is a volumetric ct dose index (ctdiv) that is usually measured by a pencil ionization chamber with active length of 100mm and polymethyl methacrylate (pmma) phantom. ctdiv depends on scan parameters such as mas, kv, collimation, tube rotation time but is independent of patient’s size and shape. for the purpose of a good estimati...

Geothermobarometry equations are based on thermodynamic principles and appear in single or multi-variant functions. The number of variants for a specific composition or reaction usually is reduced into 2 involving temperature (T) and pressure (P). Since most of planned equations have two passive or variant P and T, using these equations should be with special care. It is very effective to use g...