[1] X-Tek Systems Ltd (Nikon Metrology UK Ltd), Unit 5, Icknield Industrial Estate, Tring, United Kingdom
[2] Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300, Leuven,3001, Belgium
[3] Department of Nuclear Medicine & Molecular Imaging, KU Leuven, UZ Herestraat 49, Leuven,3000, Belgium