  Virtual reality (VR) training simulators of liver needle insertion in the
hepatic area of breathing virtual patients currently need 4D data acquisitions
as a prerequisite. Here, first a population-based breathing virtual patient 4D
atlas can be built and second the requirement of a dose-relevant or expensive
acquisition of a 4D data set for a new static 3D patient can be mitigated by
warping the mean atlas motion. The breakthrough contribution of this work is
the construction and reuse of population-based learned 4D motion models.
