The objective of the study is to construct a noninvasive approach using 124I-labeled monoclonal antibody radiotracer to detect the Thomsen-Friedenreich antigen (TF-antigen, CD176) expression of tumor lesions in patients with solid tumors and to identify patients benefiting from TF-antigen targeting treatment.

Analysis plan: 1. Recruit 3-5 participants to analyze preliminary pharmacokinetic/first-in-human dose (FIH), major organ distribution, and tumor uptake information via whole-body PET/CT imaging; 2. Recruit 20 participants to analyze in vivo safety and tumor targeting information; 3. Recruit all participants for a final summary.

Inclusion Criteria:

1. Age ≥ 18 and ≤ 75 years, male or female;
2. ECOG performance status score of 0 or 1;
3. Expected survival time ≥ 6 months;
4. At least one measurable tumor lesion exists according to RECIST 1.1 criteria (e.g., lung cancer, gastric cancer, colorectal cancer, breast cancer, pancreatic cancer, hepatocellular carcinoma). The lesion must be eligible for biopsy within one month before or after a PET scan, and the patient must be able to provide 2-3 tissue slices of the lesion;
5. Subjects must fully understand and voluntarily agree to participate in the study and sign an informed consent form.

Exclusion Criteria:

1. Pregnant or breastfeeding women, or women planning to become pregnant during the study period or within three months after drug administration, as well as individuals donating sperm or eggs;
2. Individuals known or suspected to be allergic to the investigational drug or any of its components;
3. Individuals with significantly impaired liver or kidney function;
4. Individuals unable to comply with PET examinations or those with conditions such as claustrophobia that prevent them from undergoing PET scans.

Malignant tumor patients or suspected patients