Dose 2016

Derivation of formalism to convert ionisation in plastic to dose to water Derivation of depth scaling factor

Distance scaling (range-scaling factor)

Field size (radius)

electron density in terms of electrons/g

depth [cm]

z

r

we, ρ = =

eqs,

eqs,

ρ

z

r

ref w,

ref w,

se,

Valid when mass attenuation coefficient proportional to electron density. i.e mono-energetic beams and low energy MV beams