The F-factor, in
diagnostic radiology
Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to rev ...
, is the conversion factor between
exposure
Exposure or Exposures may refer to:
People
* The Exposures, a pseudonym for German electronic musician Jan Jeline
Arts, entertainment, and media Films
* ''Exposure'' (film), a 1932 American film
* ''Exposure'', another name for the 1991 movie ...
and
absorbed dose
Absorbed dose is a dose quantity which is the measure of the energy deposited in matter by ionizing radiation per unit mass. Absorbed dose is used in the calculation of dose uptake in living tissue in both radiation protection (reduction of harmf ...
. In other words, it converts between the amount of ionization in air (
roentgens or, in SI units,
coulombs per kilogram of absorber material) and the absorbed dose in air (
rads
RAD or Rad may refer to:
People
* Robert Anthony Rad Dougall (born 1951), South African former racing driver
* Rad Hourani, Canadian fashion designer and artist
* Nickname of Leonardus Rad Kortenhorst (1886–1963), Dutch politician
* Radley Rad ...
or
grays
Grays or Greys may refer to:
Places
* Grays Bay, Nunavut, Canada
* Grays, Essex, a town in Essex, England
** Grays railway station
** Grays School
* Grays, Kent, a hamlet in Kent, England
* Rotherfield Greys or Greys, a village in Oxfordshire, En ...
). The two determinants of the F-factor are the
effective atomic number (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.
Radiation-related quantities
The following table shows radiation quantities in SI and non-SI units.
See also
*
Gray (unit)
The gray (symbol: Gy) is the unit of ionizing radiation dose in the International System of Units (SI), defined as the absorption of one joule of radiation energy per kilogram of matter.
It is used as a unit of the radiation quantity absorb ...
*
Sievert
The sievert (symbol: SvNot be confused with the sverdrup or the svedberg, two non-SI units that sometimes use the same symbol.) is a unit in the International System of Units (SI) intended to represent the stochastic health risk of ionizing radi ...
*
Equivalent dose
Equivalent dose is a dose quantity '' H '' representing the stochastic health effects of low levels of ionizing radiation on the human body which represents the probability of radiation-induced cancer and genetic damage. It is derived from the ph ...
*
Relative biological effectiveness
In radiobiology, the relative biological effectiveness (often abbreviated as RBE) is the ratio of biological effectiveness of one type of ionizing radiation relative to another, given the same amount of absorbed energy. The RBE is an empiric ...
References
Bushberg et al., 2002. ''The Essential Physics of Medical Imaging.'' Philadelphia: Lippincott Williams & Wilkins. (p. 55)
Radiology
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