Dose 2016
Approximations in dose calculation
Infinite slab approximation: doses at phantom boundaries
The depth ( z ) is generally assumed to be constant within the lateral integration plane during calculation of the scatter dose to a point.
ρ 0
ρ 0
z
z
Primary depositio n volume
Primary depositio n volume
Calculatio n point
Calculatio n point
Backscatter overestimated
Ideal case
ρ 0
ρ 0
z
z
z
ρ 0
Primary depositio n volume
Primary depositio n volume
Primary depositio n volume
Calculatio n point
Calculatio n point
Calculatio n point
Scatter overestimated
Scatter underestimated
Errors cancel (roughly)
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