Brain Tumours

Coverage of the target volume: cribriform plate - To include the cribriform fossa in the CTV and allowing an additional appropriate margin to the PTV, the PTV frequently includes the lenses.

- We consider it necessary to frequently deliver a higher dose to the lens (accepting an increased probability of later cataract development) than not adequately cover the cribriform plate. - SFOP group suggested that the edge of the shielding block/ MLCs is at least 5 mm below the cribriform fossa as this field edge definition is not associated with an increase risk of frontal recurrence