Physics Bucharest 2017

Add random errors  M PTV

= 2.5Σ + 0.7σ

Impact of random motion on tumor dose: - Narrow PTV-margin: cells at PTV edge get

>95% in some fractions, << 95% dose in others (asymmetric) - Effectively, tumor experiences the planning dose distribution that is blurred

For an infinite number of fractions:

Planned (static) dose

Blurred dose

G 

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