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...
