Angiotensin-converting enzyme 2 (ACE2) plays an important role in renin-angiotensin system (RAS) and has been reported to relate with cancer. Recently, it has also been proved as the key target for COVID-19 infection.

DX600 is a polypeptide that can specific binding to ACE2 specifically with nanomolar affinity reported in literature. This study constrcuted a radio-tracer, DX600 Labeled by PET Radionuclide, to monitoring biodistribution ACE2 in human beings, evaluate the detection ability of radio-tracer in ACE2 over-expression tumors and dynamic changes of ACE2 expression under therapy.

Inclusion Criteria:

• Age 18-75 years old; both sex;
• ECoG 0 or 1;
• Patients that would undergo biopsy or surgical operation with high ACE2 expression tumors such as colorectal cancer, renal cancer, pancreatic cancer, gastric cancer, liver cancer, lung cancer, brain cancer or suspected tumor.
• use 18F-FDG PET/CT as baseline evaluation

Exclusion Criteria:

• Significant hepatic or renal dysfunction;
• Is Pregnant or ready to pregnant;
• Cannot lie on their back for half an hour;
• Suffering from claustrophobia or other mental diseases;
• Refusal to join the clinical study;