The White Rabbit IMRT QA Phantom consists of seven cylindrical disks. The disks are 28cm in diameter and have a central hole in four of the disks to accept an ion chamber A holder lets the cylinder lay on its side for irradiation simulating the patient position. A second hole near the periphery is used to measure tangential treatment fields. Solid disks can be removed from the phantom and used to irradiate planar dose films or a film can be put in the phantom for combination field exposures. Positioning the phantom accordingly can produce films in coronal, sagittal or other planes.

The White Rabbit is constructed of Ultra-high molecular weight polyethylene which has a density of 0.928 - 0.941 g/cc (depending on the source of reference).