Initial Characterization of the SAFIR Prototype PET-MR Scanner

Christian Ritzer*, Robert Becker, Alfred Buck, Volker Commichau, Jan Debus, Lubomir Djambazov, Afroditi Eleftheriou, Jannis Fischer, Peter Fischer, Mikiko Ito, Parisa Khateri, Werner Lustermann, Michael Ritzert, Ulf Roser, Markus Rudin, Ilaria Sacco, Charalampos Tsoumpas, Geoffrey Warnock, Matthias Wyss, Agnieszka Zagozdzinska-BochenekBruno Weber, Gunther Dissertori

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

9 Citations (Scopus)
9 Downloads (Pure)


The SAFIR collaboration is currently developing a high-rate positron emission tomography (PET) insert to study fast kinetic processes in small animals. Our insert is designed for simultaneous image acquisition with a preclinical 7 T magnetic resonance (MR) imaging device. In contrast to existing preclinical PET scanners and inserts, our hardware is optimized for high-rate measurements with source activities up to 500 MBq. As a first step, the SAFIR Prototype insert was constructed. This already incorporates the final components, but has a reduced axial field-of-view (35.6 mm). We use lutetiumyttrium oxyorthosilicate crystals (2.12 mm x 2.12 mm x 13 mm) one-to-one coupled to silicon photomultipliers. All analog signals are digitized within the insert. We use 49 MR-compatible dcdc converters in the insert to provide the power to all readout electronics. After shimming, no degradation of the homogeneity of the static B-0 field in the MR scanner was observed. During full operation, we saw a minor reduction in the signal-to-noise ratio of the MR data of 4.9%. With a low activity point source (22Na 0.65 MBq) we obtained a coincidence energy resolution of 13.8% full width at half maximum (FWHM) and a coincidence timing resolution of 194 ps (FWHM). First PET/MR rat brain and high-rate mouse cardiac images (84.9 MBq) are shown in this article.

Original languageEnglish
Pages (from-to)613-621
Number of pages9
JournalIEEE Transactions on Radiation and Plasma Medical Sciences
Issue number5
Early online date18-Mar-2020
Publication statusPublished - Sept-2020
Externally publishedYes


  • High rate PET
  • instrumentation
  • molecular imaging
  • multimodality imaging
  • positron emission tomography (PET)/magnetic resonance (MR)
  • preclinical PET insert

Cite this