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The “shift” part: systematic
•
Systematic uncertainties (typically preparation errors) cause a
shift
of the (blurred) dose distribution.
•
Again, we assume the systematic uncertainties within a certain
population of patients to be described by a normal distribution
Average uncertainty per patient: systematic
SD per patient: random, σ
M
sys
to ensure that for 90% of all
systematic errors, the CTV
receives 95% of the prescription dose
The PTV 2017 - D. Verellen
SD of all systematic uncertainties: Σ