Utility of daily image guidance with intensity-modulated radiotherapy for tumors of the base of skull.

Abstract

This study was carried out to report our experience using intensity-modulated radiotherapy (IMRT) with daily image-guided radiotherapy (IGRT) for tumors involving the base of skull. In all, 100 patients were prospectively treated with IMRT to a median dose of 64 Gy (range, 45-70 Gy). Daily helical megavoltage computed tomography (MVCT) scans were obtained as part of an IGRT registration protocol for patient alignment. The 2-year local-regional control was 91%. A total of 3295 daily MVCT scans were obtained. The mean shift to account for interfraction motion was 1.18 ± 1.75 mm, 1.81 ± 1.34 mm, and 1.33 ± 1.19 mm for the medial-lateral (ML), superior-inferior (SI), and anterior-posterior (AP) directions, respectively. Pretreatment shifts of >3 mm occurred in 10%, 26%, and 18%, in the ML, SI, and AP directions, respectively. The feasibility and efficacy of daily IGRT as a complement to IMRT for skull base were demonstrated.