268 / 1542
Basic Theorems and Principles
ABSORBED DOSE
: kinetic energy transferred per unit mass (J/kg = Gy)
Charged particles (created by primary photons)
transfer
some of
kinetic
energy to medium
-> absorbed dose and lose some of their
energy in the form of radiative losses (bremsstrahlung, etc)
Absorbed dose is the mean energy transfer imparted by ionizing
radiation to matter with volume V
Mean energy transfer = E(entering V) – E(leaving V)
Because electrons travel in the medium and deposit energy along
their tracks,
absorption of energy does not take place at same
location as energy transfer by KERMA (Energy transfer from
indirectly ionizing radiation to directly ionizing)