ASMR

Keeping things in perspective

• Margin recipe assumptions

– Perfectly conformal dose distribution – Large and smooth (compared to penumbra size) CTV – Translational errors only – Large number of fractions (for the 0.7 part)

• Real life – Not conformal, i.e. margin will depend on shape of dose distr. – Not smooth – Lots of changes  translations, rotations, shape changes, delineation errors… – Any number of fractions (or very few!)