VMAT Grid Therapy: A Widely Applicable Planning Approach

PurposeTo describe a novel and practical volumetric modulated arc therapy (VMAT) planning approach for grid therapy.Methods MaterialsDose is prescribed to 1.5-cm diameter spherical contours placed throughout the gross tumor volume (GTV). Placement of spheres variable, but they must maintain at least 3-cm (center center) separation, edge any sphere be 1 cm from organ risk (OAR). Three concentric ring structures are used during optimization confine highest doses center maximize dose sparing between them. The end result alternating regions high low GTV minimal OARs. High-intensity flattening filter-free (FFF) modes efficiently deliver plans, entire treatments typically take only 15 20 minutes.ResultsThe illustrated with 2 examples treated our institution. Patient #1 had 1703-cm3 mediastinal mass was Gray (Gy) 24 within GTV. #2 3680-cm3 abdominal 18 Gy 32 Both patients received additional consolidative radiation approximately week after initial VMAT treatment. Each patient experienced marked reduction in size symptomatic relief without treatment-related complications.ConclusionsWe have described detail that can delivered clinically time span. especially useful tumors surrounded by sensitive critical structures. As many centers offer treatments, widely accessible readily implemented once appropriate selection delivery processes established.