The increase in hydrophilicity by introducing a (HE)3-tag at the N-terminus and eliminating the positive charge at the C-terminus by using a NODAGA chelator lead to the fastest clearance from blood and best tumor-to-liver ratio, resulting in improved contrast for imaging of HER3-expression using gallium-labeled anti-HER3 affibody molecules. The gene discussed is ERBB3; the disease is neoplasm.