  Human body is a complex dynamic system composed of various sub-dynamic parts.
Especially, thoracic and abdominal organs have complex internal shape
variations with different frequencies by various reasons such as respiration
with fast motion and peristalsis with slower motion. CT protocols for abdominal
lesions are multi-phase scans for various tumor detection to use different
vascular contrast, however, they are not aligned well enough to visually check
the same area. In this paper, we propose a time-efficient and accurate
deformable registration algorithm for multi-phase CT scans considering
abdominal organ motions, which can be applied for differentiable or
non-differentiable motions of abdominal organs. Experimental results shows the
registration accuracy as 0.85 +/- 0.45mm (mean +/- STD) for pancreas within 1
minute for the whole abdominal region.
