Fig. 1

Representative patient dose distributions of volumetric modulated arc therapy and magnetic resonance image-based intensity modulated radiation therapy. Dose distributions in the axial, coronal, and sagittal planes of volumetric modulated arc therapy (VMAT) of representative patients, namely, patients A (a) and B (c), are shown. Those of magnetic resonance image-based intensity modulated radiation therapy (MRI-based IMRT) using a linear accelerator with a magnetic resonance imaging system are shown for patients A (b) and B (d). The planning target volume of VMAT were generated by adding an isotropic margin of 5 mm from the internal target volume, whereas those of MRI-based IMRT were generated by adding an isotropic margin of 3 mm from the gross tumor volume