Physics Bucharest 2017

Basic Dose Calculation Principles

Simplified depth dose formalism

• e -( m • d)

/f+d) 2

DD(d) %

=D max • (f+d m

• K s

primary component

scatte r

D max

max dose,ie 100% for PDD

f distance from source to surface d m or depth to D max d is depth in tissue K s is the scatter

“For a given photon beam at a given SSD, the dose rate at point P depends on the field size A; the larger the field size, the larger the dose. “ IAEA Handbook Chapter 6