Development of real 4D CT with real-time reconstruction and display

Since we developed a 256-slice CT-scanner for four-dimensional (4D) imaging of moving organs three years ago, we have evaluated its physical performances, and carried out animal experiments and human studies. These studies suggest that the 256-slice CT-scanner may be useful for examining of moving organs such as heart or lung. In order to investigate usefulness of 256-slice CT-scanner which was suggested by the previous studies, we have developed a new 256-slice CT-scanner (the second model) with improved specifications. Its scan time is 0.5 s/rotation in the highest speed. We can carry out real-time reconstruction and display of dynamic 3D images (4D images) with this scanner. The image characteristics such as spatial resolution, noise and low-contrast detectability were evaluated with stationary phantoms in a single rotation. All characteristics have been improved from those of the first prototype with remarkable improvement of low-contrast detectability and slice sensitivity profile. We are now carrying out clinical study for patients with heart disease and lung cancer to examine its potentials for cardiology and 4D radiation therapy planning