Anti-IGFBP7 sdAb have advantages compared with other predominantly peptide-based strategies, including high specificity to the target, while retaining appropriate pharmacokinetic characteristics for imaging applications, including PET; further studies comparing anti-IGFBP7 sdAb with other brain tumour-vessel targeting molecular imaging agents in PET studies are warranted. The gene discussed is IGFBP7; the disease is brain neoplasm.