Abstract: A method and apparatus for balancing a statically unbalanced system, particularly useful in balancing X-ray and mammography systems having an X-ray source and detector mounted to a rotational arm, includes a linear actuator coupled to a drive mechanism which synchronizes the activation of the linear actuator with the rotation of the arm of the mammography system. The drive mechanism can include intermeshed gears, wheels or gears coupled together with a chain or belt, or other types of synchronizing drives. The balancing mechanism reduces the amount of force necessary to rotate the arm and decreases the overall weight of the system by eliminating the need for counterweights to maintain balance of the system.

Abstract: MRI images are acquired as the patient moves a joint through a range of motion. The angle of joined limbs is measured during the scan, and the measured angles are attached to corresponding images for display therewith. In one embodiment the angles are measured using interleaved navigator acquisitions from which limb orientation can be determined.