To evaluate the potential usefulness of 68Ga-DOTA-F2 positron emission tomography/computed tomography (PET/CT) for the diagnosis of primary and metastatic lesions in various types of cancer, compared with 18F-FDG PET/CT.

Quinoline-based fibroblast activation protein (FAP) inhibitors (FAPIs; e.g., FAPI-04 and FAPI-46), which have shown promising results in the diagnosis of cancer and various other diseases in recent years, have become the focus of much productive research. Despite this, one major issue is that these FAPI molecules have a relatively short tumor retention time, which may limit their use in targeted radionuclide therapy applications. As a result, 68Ga-DOTA-F2, a novel dimeric FAPI molecule, was developed to increase tracer uptake and retention in tumors for potential therapeutic or theranostic applications. In preclinical study, 68Ga-DOTA-F2 has shown better tumor uptake and longer tumor retention time than 68Ga-FAPI in mouse tumor models. Our study will assess image quality and evaluate the diagnostic performance of 68Ga-DOTA-F2. Patients with histologically confirmed malignant tumors will be prospectively recruited in this study.

Inclusion Criteria:

1. Subject is aged 18 years or older
2. Signed Informed Consent
3. Subject is pathologically confirmed with a malignant tumor
4. Subject is judged to be in good general condition by the investigator based on medical history, physical examination including vital signs and clinical laboratory tests, besides the diagnosis of malignant tumor
5. Female subjects should be post-menopausal or surgically sterile or using effective contraceptive with the negative pregnancy test

Exclusion Criteria:

1. Subject has a previous or ongoing recurrent or chronic disease, other than malignant tumor, at high risk to interfere with the evaluation of the trial according to the judgment of the investigator
2. Subject with non-malignant lesions;
3. Subject with the inability or unwillingness of the research participant, parent or legal representative to provide written informed consent.
4. Subject is potentially pregnant (serum and urinary hCG test will be performed in women where pregnancy is not excluded) or is breast-feeding