936 / 1544
Changes in anatomy over the course of treatment
•
10 H&N – oropharingeal ca pts, IMRT
•
Three radiation oncologists delineating OARs, three contouring
sessions one week apart
•
Mean difference in total volume for each OAR was 1 cm3 for
each OAR.
•
Considerable spatial differences in contours, ipsilateral parotis
and pharingeal constrictors showing most variability.
•
Despite substantial differences in OAR contours,
optimization was barely affected with less than a 1 Gy
difference in dose
(Feng
et al
, 2012)