Dose Course 2018_Flipping book

Plan Evaluation: DVH Metrics

• Ideal: Summarize DVH into a Single Index • How do we summarize a DVH? – Mean Dose? – Median Dose? not useful in all cases! • Reduce DVH (Power Law gives a relationship between Dose and fractional volume for a given NTCP) – Effective Volume Method [Converting bin volumes into volumes for a particular reference dose] (V eff ) – Effective Dose Method [Converting bin doses to an equivalent dose to the whole organ] (D eff ) – Then: Substitute V eff or D eff into Lyman Equations to get NTCP as dose is now uniform to organ • Statistical Indices that describe complication and cure rates: NTCP, TCP and EUD   a i a i i DV EUD 1 ) (   =

Dublin 2018