ERBB2 and neoplasm: Direct head-to-head comparison of anti-HER2 ZHER2:342 affibody molecule and trastuzumab (labelled with 124I using the same technique) demonstrated tumour-to-blood ratio for [124I]-PIB-ZHER2:342 six hours after injection that was six-fold higher than for [124I]-PIB-trastuzumab 72 h after injection.