J Med Phys Close
 

Figure 2: Gantry at 90° position colliding with couch at 20° position for the same head neck patient; no couch position ≥±12° practically possible as it does not allow the gantry to cross ±90° position for Elekta linear accelerator. For Varian accelerator, the accessible couch angle further reduces as the isocenter to gantry end clearance is lesser than Elekta accelerators

Figure 2: Gantry at 90° position colliding with couch at 20° position for the same head neck patient; no couch position ≥±12° practically possible as it does not allow the gantry to cross ±90° position for Elekta linear accelerator. For Varian accelerator, the accessible couch angle further reduces as the isocenter to gantry end clearance is lesser than Elekta accelerators