A Relative Thoracic Cage Coordinate System for Localizing the Thoracic Organs in Chest CT Volume Data.

Thoracic organ segmentation from the three dimensional (3D) medical images always needs an initial position. We developed a relative thoracic cage coordinate system (RTCCS) for localizing the organs in chest CT volume data. To test the RTCCS, we first extracted the 3D ribs and heart-wall from the segmented atlas of male American visible human, and then we built up a RTCCS according to the position of the ribs and calculated the relative coordinate values of all the voxels in the heart-wall. Next we segmented the 3D ribs from the female American visible human CT data and built up another RTCCS on these ribs. At last we used the relative coordinate values of the male visible human's heart-wall to reconstruct a new 3D heart-wall in the thoracic cage of the female visible human CT data, getting an approximate position of the female visible human's heart.