Trop-2 Targeted PET Probes in Advanced TNBC

Inclusion Criteria: 1. Aged 18 - 75 years, male or female, with an ECOG score ≥ 2. 2. Blood routine, liver and kidney functions meet the following standards: * Blood routine: Total white blood cell count (WBC) ≥ 3.0×10⁹/L or neutrophil count (Neu) ≥ 1.5×10⁹/L, platelet count (PLT) ≥ 80×10⁹/L, hemoglobin (Hb) ≥ 80 g/L. * Liver and kidney functions: Total bilirubin (T - Bil) ≤ 1.5×ULN (upper limit of normal value), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5×ULN or ≤ 5×ULN (in case of liver metastasis), serum creatinine (SCr) ≤ 1.5×ULN. 3. Subjects with advanced triple - negative breast cancer previously diagnosed by histopathological diagnosis and imaging evaluation. 4. Expected survival time ≥ 12 weeks. 5. Clinicians assess that TROP - 2 ADC is an appropriate treatment plan for the subject at present. 6. There is at least one measurable target lesion in accordance with the RECIST 1.1 standard. 7. Subjects for whom clinicians recommend PET/CT examination for breast tumor diagnosis and staging. 8. Women of childbearing age (18 - 60 years old) must undergo a pregnancy test within 7 days before the start of the examination and the result is negative; Male and female subjects with fertility must agree to use effective contraceptive measures to ensure no pregnancy during the study period and within 3 months after the examination. 9. The subject can fully understand and voluntarily participate in this experiment, sign the informed consent form, and have good follow - up compliance. Exclusion Criteria: 1. Severe abnormalities in liver and kidney functions; 2. Women who are in the pre - pregnancy period, pregnant or lactating; 3. Those who cannot lie flat for half an hour; 4. Those who cannot provide informed consent; 5. Those suffering from claustrophobia or other mental illnesses; 6. Those known to be allergic to the investigational drugs or their excipients used in the study treatment; 7. Other situations that the researchers consider make it inappropriate to participate in the trial.