Optimization of Dynamic Neoadjuvant Therapy Strategies for HER2-Positive Breast Cancer Based on HER2-PET/CT Molecular Imaging

Inclusion Criteria:

* Voluntary participation with written informed consent obtained prior to any study-related procedures
* Age ≥ 18 years, male or female.
* Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-1
* Histologically confirmed HER2-positive (IHC 3+, or IHC 2+ with ISH amplification) stage I-III (cT1-3/cN0-2) breast cancer
* Tumor diameter ≥ 1.5 cm assessed by imaging, with at least one PET-evaluable lesion present
* Patient must have known estrogen receptor (ER) and progesterone receptor (PR) status. For Arm B, ER expression ≥ 10% and must be strongly positive.
* Adequate bone marrow, liver, and renal function: WBC \> 3.0 × 10⁹/L, ANC ≥ 1.5 × 10⁹/L, PLT ≥ 100 × 10⁹/L, Hb ≥ 10.0 g/dL; total bilirubin ≤ ULN (excluding Gilbert's syndrome), ALP ≤ 2.5 × ULN, AST/ALT ≤ 1.5 × ULN; creatinine ≤ 1.5 × ULN or creatinine clearance ≥ 50 mL/min.
* Patients who participate in the trial have good compliance and are willing to comply with the follow-up visit.

Exclusion Criteria:

* Prior treatment with any chemotherapy, anti-HER2 therapy, radiotherapy, or endocrine therapy, etc
* Locally advanced (cT4/cN3) or bilateral breast cancer
* Patients with known allergies to any active ingredients or excipients of investigational medicinal product
* Other malignancy diagnosed within 5 years prior to enrollment, excluding cervical carcinoma in situ and cured melanoma skin cancer
* Left ventricular ejection fraction (LVEF) \< 55%
* Uncontrolled hypertension (systolic \> 150 mm Hg and/or diastolic \> 100 mm Hg)
* Severely cardiovascular disease
* Current known infection with HIV, hepatitis B virus, or hepatitis C virus
* Patients with pulmonary disease requiring continuous oxygen therapy, previous history of bleeding diathesis or patient is currently receiving anti-coagulant therapy, or immunosuppressive agent
* Major surgical procedure or significant traumatic injury
* Patient has other concurrent severe and/or uncontrolled medical conditions.
* Concurrent participation in other interventional clinical trial
* History of receiving any investigational treatment within 28 days prior to randomization
* Pregnant or breast-feeding women or patients not willing to apply highly effective contraception as defined in the protocol
* Inability to lie flat or presence of psychiatric disorders such as claustrophobia