Dose Course 2018_Flipping book

Which Plan Characteristics?

Plan Characteristic

TPS Modelling

Linac Delivery

Poor modelling of T&G magnified MLC Transmission modelling issues magnified

MLC Modulation

Magnifies Gantry Resolution Limitation

Avg. MLC Speed

Increased MLC errors

MLC

MLC Speed Variation

Increased MLC errors

More sensitive to dose- grid, gantry resolution & small field output factor limitations

Delivery more sensitive to MLC errors (lower MLC speeds - dynamic errors low) Beam Stability Issues at lower Dose-Rates Increased MU errors Beam Stability Errors

Mean Gap between MLCs

Average Dose-Rate

MU

Avg. Dose-Rate Variation

Gantry

Gantry Speed Variation

Gantry Resolution

Gantry errors