, in diagnostic radiology
, is the conversion factor between rontgens
(or, in more modern units, coulombs
). In other words, it converts between the amount of ionization in air (rontgens) and the absorbed dose in tissue (rads). The two determinants are of the F-factor are the effective Z
of the material and the type of ionizing radiation
being considered. Since the effective Z of air and soft tissue is approximately the same, the F-factor is approximately 1 for many x-ray imaging applications. However, bone has an F-factor of up to 4, due to its higher effective Z.
Bushberg et al., 2002. The Essential Physics of Medical Imaging.
Philadelphia: Lippincott Williams & Wilkins. (p. 55)