ERBB2 and breast cancer: Furthermore, [225Ac]Ac-DOTA-trastuzumab co-injected with [111In]In-DOTA-trastuzumab assuming that [111In]In-DOTA-trastuzumab radiotraces the uptake of [225Ac]Ac-DOTA-trastuzumab exhibited HER2-specific uptake in s.c. 164/8-1B/H2N.luc+ human BC tumours in NRG mice, allowing tumour imaging by SPECT/CT.