Systems and methods for delivering a radiation beam using a linear accelerator (LINAC). Optimal beam alignment parameters may be determined and stored for each of N gantry angles. The beam alignment parameters may adjust a current supplied to one or more bending magnets of the LINAC and, thus, change an angle and direction of the radiation beam. An optimum beam alignment parameter for a gantry angle may be determined by adjusting the beam alignment parameter until a center of a radiation field of the radiation beam in a radiation transmission image is at a center of shadow of a radiation opaque marker, which may be placed at a radiation isocenter. The beam alignment parameters stored for the N gantry angles may be used to adjust the beam steering current as the gantry is rotated through any arbitrary gantry angle.