AB015. OA02.06: A Dosimetric Comparison of VMAT and IMPT with and Without Aperture for Thymic Cancer

Background: Due to the location of thymic cancer, proton therapy will save more normal organ dose in distal direction than conventional photon radiotherapy. But the lateral penumbra of intensity modulated proton therapy (IMPT) is usually larger than photon. One option is to use aperture for IMPT to reduce lateral penumbra. We compared volumetric modulated arc therapy (VMAT) and IMPT with aperture (IMPTa) and without aperture (IMPT) to evaluate the effect of normal organ saving for thymic cancer.