[1] Katholieke Univ Leuven, Dept Cardiovasc Sci, Herestraat 49, B-3000 Leuven, Belgium
[2] DoseVue NV, Bampslaan 21, B-3500 Hasselt, Belgium
[3] KU Leuven Kulak, Dept Phys, Etienne Sabbelaan 53, B-8500 Kortrijk, Belgium
[4] Belgian Nucl Res Ctr SCK CEN, Inst Environm Hlth & Safety, Boeretang 200, B-2400 Mol, Belgium