Systems and methods are provided for generating surface brachytherapy applicators in which catheter channel trajectories are generated laterally from both sides of a cut plane bisecting an initial model of the surface brachytherapy applicator model, thereby mitigating the effects of patient-surface-induced curvature. The catheter channels may be defined based on catheter channel trajectories that are spatially distributed, relative to the cut plane, on both sides of the cut plane, and spatially offset relative to a patient-facing surface of the surface brachytherapy applicator model. In some example embodiments, catheter channel trajectories are spaced relative to the cut plane such that neighbouring catheter channel trajectories are evenly spaced along a set of contours. Prior to fabrication, the local radius of curvature of catheter channels may be adjusted in a manual or automated manner to exceed a threshold.