Erratum: Longitudinal in vivo evaluation of bone regeneration by combined measurement of multi-pinhole SPECT and micro-CT for tissue engineering

In the Results section under subheading 'Longitudinal in vivo assessment of biomaterial-induced bone formation' " Over the following 8 weeks the plural stayed closed. " should read: " Over the following 8 weeks the defects stayed closed ". Under subheading 'Temporal and spatial in vivo assessment of hydroxyapatite deposition during bone defect regeneration – anterior-posterior axis. ' " Thereafter no significant SPECT signal as well as no increase in bone volume was observed. In contrast, the BMP-2 hydrogel samples induced a comparably stronger signal on the anterior side of the defect and already an observable signal inside the bone defect (Fig. 4B). " should read: " No significant SPECT signal as well as no increase in bone volume were observed thereafter. In contrast, after 1 week of treatment BMP-2 hydrogel samples induced a comparably stronger signal on the anterior side of the defect and already an observable signal inside the bone defect (Fig. 4B). " In the Discussion section