Dose 2016

Derivation of formalism to convert ionisation in plastic to dose to water Phantom dose conversion factor

Calculated; using basic (tabulated) interaction coefficient data; and: stopping power ratio data and chamber perturbation factors generated by Monte Carlo methods

k

Qw, s,

( ) ( ) ref

z M

Qw,

k

Directly measured

=

Qw, s,

z M

MUs equal eq Qs,

Example: at 5cm PWDT, 6MV (TPR20,10=0.668), PTW30013 cylindrical chamber

983 .0

c

=

PWDT

( (

)

M

SSD ,5

Qw,

k

004 .1

=

=

PWDT,

Qw,

)

M

SSD ,09.5

Q PWDT,

MUs equal