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Dublin 2018
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
) (
=