Disclosed is a patient positioning assembly for orientating a patient with respect to a radiation source. The patient positioning assembly includes a translatable member movable in a vertical direction between a vertically downwards first position and a vertically upwards second position. The patient positioning assembly further includes a patient support assembly mounted to the translatable member and adapted to rotate relative to the translatable member about a vertical axis. The patient support assembly is configurable between a first orientation, which sustains the patient in a seated position, and a second orientation, which sustains the patient in a generally standing position.
