Learning Objectives
To give an overview of margin concepts
Why do we use or need margins?
To provide a qualitative understanding of a margin recipe
To provide an overview of assumptions being made in the derivations of the van Herk
margin recipe
To discuss applicability of “conventional” margin concepts in hypo-fractionated / single fraction
SBRT
To discuss the effect of a limited number of fractions on random error
Explain why a random error for hypofractionated treatments results in a systematic
error
Explain how to calculate margins for single fraction and hypofractionated treatment
and provide some practical examples
How to add errors?
To discuss margins for tumors that move with respiration
To give suggestions for further reading