In early-stage HER2-positive breast cancer, neoadjuvant chemotherapy is frequently required, and pathological complete response (pCR) correlates with excellent prognosis. However, no non-invasive imaging method reliably predicts pCR, making surgery mandatory despite its aesthetic, functional, and psychological burden. Recently, new functional imaging tracers targeting the HER2 protein have been developed. Among these, \[68Ga\]Ga-NOTA-anti-HER2-sdAb is of particular interest due to its molecular characteristic; it has demonstrated favorable safety profile and ability to identify HER2+ cells in vivo. This trial evaluates its ability to predict pCR, with the prospect of paving the way for future therapeutic de escalation and surgical sparing.