A patient support system for diagnostic and/or therapeutic radiologic procedures with geometric features that eliminate or reduce imaging artifacts created by the patient support is described. The artifact reducing features can be incorporated into an add-on patient positioning device, or directly within the standard diagnostic and/or therapeutic treatment table/couch. One possible configuration is to use a wave-like design of the portion of the patient support that remains in the radiation beam path where the anatomy to be imaged is located. Other configurations may include other geometric shapes or material distributions that serve the same purpose of eliminating artifacts in radiologic images.