The purpose of this study is to use Claudin 18.2 (CLDN18.2)-targeted positron emission tomography (PET) imaging technology to evaluate its detection efficacy and diagnostic threshold for CLDN18.2-positive pancreatic cancer and gastric/gastroesophageal junction cancer, analyze the quantitative value of PET parameters in CLDN18.2 expression and their correlation with prognosis, and provide a basis for the precise selection of CLDN18.2-targeted therapy.

The investigators will number all participants, create a medical record file, and record their basic information (gender, age) as well as contact information and medical history information. One or two [68Ga]Ga-NODAGA-SNA014 PET scans will be performed according to disease stage and treatment plan. CLDN18.2 expression will be assessed by immunohistochemistry (IHC) in surgical specimens. The optimal SUV threshold and PET quantification potential for CLDN18.2 expression will be evaluated in comparison with histopathology, along with their correlation with prognosis.

Inclusion Criteria:

1. Participants with histopathologically confirmed pancreatic cancer and gastric/gastroesophageal junction cancer with claudin 18.2 expression of any level, including treatment-naive patients with upfront resectable disease, patients with post-operative recurrent disease who are or become resectable following treatment, and patients rendered resectable after neoadjuvant or conversion therapy.
2. Signed and dated informed consent form.
3. Commitment to comply with research procedures and co-operation in the implementation of the full research process.
4. Male or female participants.
5. Aged 18-75 years old.
6. Good general performance status with an expected overall survival of more than 6 months.

Exclusion Criteria:

1. Participants with prior Claudin 18.2 targeted therapy.
2. Participants with concurrent other active malignancies.
3. Participants with severe medical conditions that render them unsuitable for participation in this clinical study. Such as severe heart and lung failure, severe bone marrow suppression, severe liver and kidney dysfunction, etc.
4. Pregnant women and women who may be pregnant, women who are breastfeeding.
5. Participants with poor compliance.

Eligible inpatients and outpatients from Ruijin Hospital