152 M. François et al. externalization and feasibility of radionuclide imaging. J Nucl Med. 2010;51:259–67. 16. van den Eijnde SM, van den Hoff MJ, Reutelingsperger CP, van Heerde WL, Henﬂing ME, Vermeij-Keers C, et al. Transient expression of phosphatidylserine at cell–cell contact areas is required for myotube formation. J Cell Sci. 2001;114:3631–42. 17. Fadeel B, Xue D, Kagan V. Programmed cell clearance: molecular regulation of the elimination of apoptotic cell corpses and its role in the resolution of inﬂammation. Bio- chem Biophys Res Commun. 2010;396:7–10. 18. Li MO, Sarkisian MR, Mehal WZ, Rakic P, Flavell RA. Phos- phatidylserine receptor is required for clearance of apoptotic cells. Science. 2003;302:1560–3.