Fluroscopy is an excellent tool for the evaluation of mechanical prosthetic valves. Mitral prosthetic valve is best visualized in the RAO (right anterior oblique) cranial projection. Aortic prosthetic valve is better imaged in RAO caudal or LAO (left anterior oblique) cranial projection. Positioning is in such a way to have X-rays parallel to the valve ring plane. Undue rocking movement (more than seven degrees for aortic and more than eleven degrees for mitral) of the valve ring may indicate partial dehiscence. Decreased movement of the disks would suggest valve obstruction.