Kerma V Absorbed Dose V Integral Dose

**KERMA** is the energy transferred to electrons by photons and can be expended through collision interactions (soft collisions and hard collisions) and through radiative interactions (bremsstrahlung and electronâ€“positron annihilation).

The **ABSORBED DOSE** is defined as the mean energy e imparted by ionizing radiation to matter of mass m in a finite volume V by:

\begin{align} D = \left ( \frac{d \epsilon}{dm} \right ) \end{align}

**INTEGRAL DOSE** is the total energy absorbed by the body, and is the product of the mass of tissue irradiated and the absorbed dose; expressed as the *kilogram.Gy*.

#### When a photon beam interacts with a medium, the photon interactions release electrons with kinetic energy into the medium (Kerma) which then move on to deposit energy along ionisation tracks. The energy deposited by these electrons per unit mass is the Absorbed dose. The total absorbed energy delivered by the secondary electrons produced by a photon beam is the Integral dose.The Integral dose attempts to describe energy deposition within the whole body.

page revision: 1, last edited: 14 Jun 2008 11:22