Usefulness of Semi-cylindrical Beam Spoiler in Treatment of Early Glottic Cancer Using 6 MV Photon Beam

Abstract

Background/Aim: To assess the dosimetric influence of a semi-cylindrical beam spoiler (sCBS) for the treatment of early glottic cancer using a 6 MV photon beam. Patients and Methods: The 2D dose distributions were also calculated and measured with and without the sCBS and with a 0.5 cm thick bolus. A retrospective study of 8 patients treated between 2012 and 2018 was performed. Results: The 2D dose distributions obtained from the treatment planning system (TPS) and film measurements were in good agreement. In the planning study, the V95%, V100%, conformal index (CI), and homogeneity index (HI) of all pPTVs for the sCBS plans were better than those for the open field plans (p<0.01). Especially, sCBS plans had better skin sparing effect than bolus plans (p<0.05). Conclusion: The sCBS of the 6 MV photon beam could be a useful tool for the treatment of early glottic cancers.