**Author details**

Ingrid Hilger, Katja Dahlke, Gabriella Rimkus and Christiane Geyer *Jena University Hospital, Germany* 

Frank Seifert, Olaf Kosch, Florian Thiel *Physikalisch-Technische Bundesanstalt Berlin, Germany* 

Matthias Hein, Francesco Scotto di Clemente, Ulrich Schwarz, Marko Helbig, Jürgen Sachs *Ilmenau University of Technology, Germany* 
