Dosimetric comparison among dynamic conformal arc therapy, coplanar and non-coplanar volumetric modulated arc therapy for single brain metastasis

Abstract In the delivery of stereotactic radiosurgery (SRS) by linear accelerator (LINAC), dynamic conformal arc therapy (DCAT) with non-coplanar beams is conventionally used. However, volumetric modulated (VMAT) can improve target conformity, thereby decreasing dose to organs at risk inversed planning methods, but few studies have directly compared DCAT and VMAT without in patients single brain metastasis. We therefore conducted a study compare distribution DCAT, using only coplanar (CoVMAT) arcs (NcVMAT) treatment CoVMAT NcVMAT plans were created for 15 patients. The three modalities terms coverage, normal tissue, monitor units (MUs) beam-on time. Both conformity indices (RTOG-CI IP-CI) as well D98% gross volume (GTV) significantly better than plans. Comparisons doses tissue revealed that V20Gy, V15Gy, V12Gy, V10Gy V5Gy smaller based on other two modalities. MUs larger those plans, time was longer Compared improved reduced V5Gy.