http://www.mdpi.com/journal/atoms Latest open access articles published in Atoms at http://www.mdpi.com/journal/atoms http://www.mdpi.com/2218-2004/1/1/2 90Y is traditionally considered as a pure β– emitter. However, the decay of this radionuclide has a minor branch to the 0+ first excited state of 90Zr at 1.76 MeV, that is followed by a β+/β– emission. This internal pair production has been largely studied in the past because it is generated by a rare electric monopole transition (E0) between the states 0+/0+ of 90Zr. The positronic emission has been recently exploited for nuclear medicine applications, i.e. positron emission tomography (PET) acquisitions of 90Y-labelled radiopharmaceuticals, widely used as therapeutic agents in internal radiation therapy. To date, this topic is gaining increasing interest in the radiation dosimetry community, as the possibility of detecting β+ emissions from 90Y by PET scanners may pave the way for an accurate patient-specific dosimetry. This could lead to an explosion in scientific production in this field. In the present paper the historical background behind the study of the internal pair production of the 0+/0+ transition of 90Zr is presented along with most up to date measured branch ratio values. An overview of most recent studies that exploit β+ particles emitted from 90Y for PET acquisitions is also provided. Atoms 2013-03-08 1 1 Review 10.3390/atoms1010002 2 12 2218-2004 2013-03-08 doi: 10.3390/atoms1010002 Marco D'Arienzo http://www.mdpi.com/2218-2004/1/1/1 There is no doubt that it is an exciting time to be studying quantum properties of atoms, molecules, and nuclei. Increasingly deep connections between long-established fields: “atomic physics”, “molecular physics”, “chemical physics”, “nuclear physics”, “scattering theory”, “nuclear magnetic resonance”, “quantum optics”, etc., are blurring old research labels. Atoms is a new open access journal with a broad scope that will aim to capture some of these exciting changes and developments, with a quantum flavor. The Editorial Board's collective expertise spans the fields involved and reflects the international communities active in these areas. Atoms 2012-12-17 1 1 Editorial 10.3390/atoms1010001 1 1 2218-2004 2012-12-17 doi: 10.3390/atoms1010001 James Babb