IMRT

Surrogate value: COM Single Visicoil marker vs. COM GTV Fiducial marker surrogate value for GTV position

“ Max deviation ”

Ex. 1

LAT

AP

CC

1.2 mm in CC

(CT slice 2 mm)

(x,y,z) COM , Visicoil =(x,y,z) COM,GTV +Cte

Ex. 2

LAT

AP

CC

+ Regular verification of marker surrogate value on CT imaging