The 4th International Workshop on Computational Phantoms for Radiation Protection, Imaging, and Radiotherapy, hosted by IT'IS/ETH on behalf of the Consortium of Computational Human Phantoms, was held May 20th to 22nd, 2013, in Zurich, Switzerland. Six papers presented during this workshop are highlighted in a special section of the 59th volume of Physics in Medicine and Biology, available online as of September 21st. This selection includes the description by Gosselin et al., of the ViP 3.0, the new version of IT’IS Virtual Population. The seventh contribution to this special issue is a fascinating review of fifty years of progress in computational phantoms. Its author, George Xu, one of the pioneers in the field, also co-authored the preface of this special edition together with Niels Kuster.