ESTRO Brachytherapy for Prostate Cancer 2018
Planning Target Volume
PTV
The PTV surrounds the CTV with a margin to compensate for the different types of variations and uncertainties of treatment delivery to the CTV.
The PTV is a geometrical concept, introduced for treatment planning.
A margin must be added to the CTV
• to compensate for expected physiological movements and variations in size, shape and position of the CTV during therapy (internal margin) • for uncertainties (inaccuracies and lack of reproducibility) in patient irradiation.
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