Optical Imaging

Near-infrared in vivo fluorescence imaging was performed with an In-Vivo MS FX PRO small animal imaging system (Bruker Biospin Corporation, Woodbridge, CT, USA) after the PET/CT investigation. Mice injected with the different conjugates were sacrificed 24 h p.i. and excised bones of the lower limbs were imaged. An appropriate filter set (λex = 710 nm and λem = 790 nm) was used for acquiring the fluorescence of the IRDye800CW-conjugates ex vivo. Identical illumination settings (acquisition time = 30 s, filters = 710/790 nm, f-stop = 2.8, field of view = 100 mm, and binning = <sup>2</sup> <sup>×</sup> 2) were used for image acquisition and fluorescence emission was normalized to photons/s/mm<sup>2</sup> . Acquired images were analyzed using Bruker MI SE software (Bruker Biospin Corporation, Woodbridge, CT, USA).
