Case study: Dosimetric comparison of VMAT, IMRT and 3DCRT techniques for left-sided breast cancer treated in deep inspiration breath-hold

Abstract

The aim of this case study was to compare 3D conformal radiotherapy (3DCRT) plans for patients treated for left-sided breast cancer (whole breast without positive lymph nodes in deep inspiration breath-hold (DIBH)) to volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) plans. The original clinical plans used tangential field-in-field 3DCRT technique with a combination of 6 MV and 18 MV photon beams. VMAT and IMRT plans were based on several previously published techniques and used 6 MV beams. Two patients were included in this case study and 4 plans were created and compared for each one. All plans were compared in terms of tumour coverage, gradient measure and conformity index, doses to organs at risk (OARs), the volume of body receiving 5 Gy and also the number of Monitor Units (MUs). While better tumour coverage and conformity was achieved with IMRT and VMAT plans, OARs were better spared with the 3DCRT technique, which also resulted in the lowest dose bath and number of MUs.