A Dielectric Wall Accelerator (DWA) is a compact linear particle accelerator concept designed and patented in the late 1990s, that works by inducing a travelling electromagnetic wave in a tube which is constructed mostly from a dielectric material. The main conceptual difference to a conventional disk-loaded linac system is given by the additional dielectric wall and the coupler construction. Possible uses of this concept include its application in external beam radiotherapy (EBRT) using protons or ions.