Dose Course 2018_Flipping book

Dose deposition physics:

• Dose is deposited through electrons set in motion by the photon interactions

• Mean free path between electron interaction sites is nanometers (biomolecule size) - but the complete electron path length can be up to 10 cm in lung, less in other tissues • For fields smaller than the actual electron range, the dose varies strongly with local density variations and field size

• For fields larger than the actual electron range, the dose varies less and is simpler to calculate

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