In one embodiment, a portable X-ray imaging system 10 is provided with a base unit 12 and at least one front wheel 14 on which the base unit is mounted. The base unit 12 is also mounted on a pair of rear wheels 16. The imaging system 10 is provided with a suspension system 34 coupled to the base unit and to the rear wheels. The suspension system 34 is arranged to permit flexible movement of the base unit and the rear wheels with respect to one another.