Gradient-index Beam reshaping 1 Brain metastasis 1 Computation theory 1 Conformity index 1 Control approach 1 Dosimetry 1 Eigenvalues and eigenfunctions 1 Electric fields 1 Energy 1 HyperArc 1 Hyperarc 1 Index designs 1 Index of refraction 1 Optimal control systems 1 Optimal control theory 1 Optimal controls 1 Plan quality 1 Quality control 1 Radiochromic film 1 Radiotherapy 1 Refractive index 1 Slowly varying amplitudes 1 Stereotactic radiosurgery 1 Stereotactic radiotherapy 1 Technological applications 1 Tracking (position) 1 Tracking techniques 1 Waveguide index 1 Waveguides 1