Gynae BT_Lucknow_2018

ITV and PTV



ITV: Internal variations 

Position, size and shape of CTV • Tumour shrinkage • Organ movement • Organ deformation



PTV: External variations  Beam positioning 

Patient set-up (e.g. uncertainties when setting up according to skin marks)

 If no considerable internal variations are present  Expansion may be performed directly from CTV to PTV

 ITV and PTV margins are not directly “additive”

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