Basic Clinical Radiobiology 2017

Lyman model of dose-volume effects in normal tissue

1 2 π

−∞ u ( D , V ) ∫

⋅ x 2 ) dx

NTCP ( D , V ) =

exp( − 1 2

⋅

( V )

D − D m ⋅ D

0 < n < 1 Larger n , more volume effect

u ( D , V ) =

50

( V )

50

(1)

D

( V ) =

D

50

( see BCR book, Ch 5.9 )

50

V n D 50 = uniform dose producing 50% incidence of specific effect n = denotes influence of volume effect in organ of interest m = inverse of dose response curve gradient