EGFR and neoplasm: Following in vivo SPECT imaging, the uptake of anti-EGFR nanobody 99mTc-D10 in A431 tumours was confirmed by ex vivo biodistribution analyses in all six animals with an uptake of 2.27% ID/g ± 0.68 (Fig. 3a) resulting in a tumour to blood ratio of 12.1 ± 3.5 and a tumour to tissue (muscle) ratio of 25.6 ± 18.8 (Fig. 3c, Table 2).