Figure 2

Schematic representation of the foot-camera (FC) angle measurement. The position of the vertical axis of the gamma camera was projected using a manual laser level device placed on the center of the face of the gamma camera and producing a fan beam of light perpendicular to the ground (dotted line (a*)). The projected axis was marked on the floor with chalk (dotted line (a)).The mid-sagittal foot-axis is indicated by continuous line (b). To calculate the FC angle (c), the Law of Cosines was applied. Three distances were measured: the distance from the foot and gamma camera axes intersection to the tip of the foot (portion of the continuous line (b)), the distance from the foot and gamma camera axes intersection to the point vertically below the center of the gamma camera face (portion of the dotted line (a)); and the distance from the tip of the foot to the point vertically below the center of the gamma camera face (dashed and dotted line (d)).