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Calculation vs measurement of absorbed dose
Measurement (of ionization ) only at time of delivery of
dose
For retrospective or planned dose need theoretical
description
Calculation requires description of radiation fields in
terms of sources of particles, their interactions and a
description of receptors
•Allows calculation of flow in and out of a volume of
interest
Deterministic
•Particles subject to transport equations so can
calculate values at any point in time
Monte Carlo approaches (stochastic)
• Track individual particles
8
Requires appropriate definition of ‘number of particles’