Dose Course 2018_Flipping book

Physical processes in MV photon beams

Photon radiant energy exiting the target

Fluence engine

Treatment head & air

Interactions, predominantly in the flattening filter

Contaminant charged particles

Electron con- tamination dose

Contaminant charged particle energy deposition

Primary photon energy

Head scatter photon energy

Patient

Primary charged particle kinetic energy

Scatter photon energy

Head scatter charged particle kinetic energy

Scatter photon

Dose engine

Primary dose

Primary energy deposited

Scatter charged particle kinetic energy

Scatter charged particle kinetic energy

Bremsstrahlung and annihilation photon energy

Bremsstrahlung and annihilation photon energy

Head scatter energy deposited

Scatter energy deposited

Scatter energy deposited

Bremstrahlung and annihilation charged particle kinetic energy

Bremstrahlung and annihilation charged particle kinetic energy

Bremsstrahlung plus annihilation energy deposited

Bremsstrahlung plus annihilation energy deposited

Direct beam phantom scatter dose

Head scatter dose

3

Ahnesjö and Aspradakis, PMB 44 (1999), R99-155