Figure 4: The setup for two-step translation dynamic field-edge matching TBI. (a) The superior field irradiates the upper body with the B-leaves moving in. The dynamic field edge is aligned with the inferior line at a gantry angle of 349° ( ). (b) After shifting the patient, the inferior field irradiates the lower body with the field edge of the A-leaves aligned with the superior line at a gantry angle of 11°. indicates the isocenter of the linear accelerator. + indicates the central axis of the dynamic field.