Investigation of the Radiotracer Uptake of [68Ga] MDM2/MDMX Peptide at Lesion Sites in Patients with Malignant Tumors, and Evaluation of the Capability of [68Ga] MDM2/MDMX Peptide to Detect Overexpression of MDM2/MDMX in Tumor Patients, Particularly Those with Recurrent or Advanced Disease.

Inclusion Criteria:

1. Ages 18 to 75 years, both males and females are eligible;
2. Participants must meet the following criteria for blood routine and liver/kidney function tests: Complete blood count: WBC ≥ 4.0 × 10^9/L or neutrophils ≥ 1.5 × 10^9/L, platelets ≥ 100 × 10^9/L, hemoglobin ≥ 90 g/L; prothrombin time (PT) or activated partial thromboplastin time (APTT) ≤ 1.5 times the upper limit of normal (ULN); liver and kidney function: Total bilirubin ≤ 1.5 times the upper threshold limit (ULT), ALT/AST ≤ 2.5 ULN or ≤ 5 ULT for participants with liver metastasis, alkaline phosphatase (ALP) ≤ 2.5 ULN (if bone or liver metastases are present, ALP ≤ 4.5 ULN); Blood urea nitrogen (BUN) ≤ 1.5 × ULT, serum creatinine (SCr) ≤ 1.5 × ULT;
3. Normal cardiac function;
4. An expected survival of ≥ 12 weeks;
5. Good follow-up compliance;
6. According to RECIST 1.1 criteria, there must be at least one measurable target lesion;
7. Women of childbearing age (15-49 years) must have a negative pregnancy test conducted within 7 days prior to enrollment; patients of childbearing potential must agree to use effective contraceptive methods to ensure they do not conceive during the study and for three months after examinations;
8. Patients recommended for PET/CT evaluation for tumor diagnosis and staging by a clinician;
9. Participants must fully understand the study and voluntarily participate, and must sign an informed consent form.

Exclusion Criteria:

1. Severe abnormalities in liver and kidney function as well as hematological parameters;
2. Patients who are planning a pregnancy;
3. Pregnant or lactating women;
4. Individuals unable to lie flat for thirty minutes;
5. Individuals who refuse to participate in this clinical study;
6. Individuals suffering from claustrophobia or other psychiatric disorders;
7. Other conditions deemed by the researchers as unsuitable for participation in the trial.