Disclosed herein is a patient positioning apparatus for a medical device. The apparatus comprises a patient support apparatus, a support structure configured to extend between the patient support apparatus and a floor of a treatment room to support the patient support apparatus above the floor of the treatment room. The patient support apparatus is rotationally coupled to the support structure. The patient positioning apparatus comprises a rotation mechanism comprising a drive member and is configured to impart a force, via the drive member, to an underside of the patient support apparatus to thereby rotate the patient support apparatus with respect to the support structure. The rotation mechanism is attached to, and supported by, the support structure.