IMRT

Changes in anatomy over the course of treatment • 10 H&N – oropharingeal ca pts, IMRT

• CBCT prospectively acquired weekly, OARs dose/volume compared to the planned CT • Evaluation of the use of KV CBCT for dose monitoring and examine if dosimetric impact of such changes on the parotid and OARs require replanning • Patient weight loss (mean:7.5 kg) and parotid volume shrinkage was observed, but no significant excess dose to OAR

Fig. 1. Contouring parotid on cone beam computed tomography (CBCT) (b) using planning CT (a) as reference .

• No need for replanning in this patient cohort (Ho et al 2011)