Materials and Methods
Ten accelerated partial breast irradiation (APBI) patients (four right, six left) who underwent Fast‐Forward trial at our institute on TrueBeam (6MV beam) were re‐planned on Halcyon (6MV‐FFF). Three site‐specific partial coplanar VMAT arcs and an Acuros‐based dose engine were used. For benchmarking, PTV coverage, organs‐at‐risk (OAR) doses, beam‐on time, and quality assurance (QA) results were compared for both plans.