Malignant tumors pose a serious threat to human health, and early diagnosis and early treatment are crucial to improving the patient's prognosis. Nuclear medicine imaging technology injects radioisotope labeled molecules (such as monoclonal antibodies and peptides) into the body to identify and bind specific targets of different tumor cells, thereby achieving accurate early diagnosis of different tumors. Neurotensin receptor 1 (NTSR1) is overexpressed in many malignant tumors such as colon cancer, pancreatic cancer, gastric cancer, head and neck cancer, and is closely related to tumor occurrence, development and prognosis. At the same time, NTSR1 is low expressed in surrounding normal tissues, so NTSR1 is an excellent target for the diagnosis and diagnosis of the above-mentioned series of malignant tumors. Probes targeting NTSR1 have been gradually explored. FL-091 is a new NTSR1-targeted radionuclide conjugated drug (RDC) that has high affinity and specificity for NTSR1 in previous preclinical studies. Compared with conventional NTSR1 inhibitors, FL-091 has the following potential advantages: ① Potential for radiotherapy: FL-091 can combine with radioactive isotopes such as 177Lu or 225Ac to directly deliver radioactive energy to tumor cells. This radiation therapy can produce cytotoxicity in a local area, killing tumor cells while causing less damage to surrounding healthy tissues;② Selectivity and specificity: Since FL-091 is designed based on the high affinity of NTSR1, it can more selectively target tumor cells that express NTSR1. This high degree of specificity can reduce the impact on normal cells and increase the accuracy of imaging and treatment.③ Biodistribution and rapid clearance: FL-091 demonstrated optimized biodistribution characteristics, such as higher tumor uptake rates and faster clearance of normal tissues. This means it can effectively deliver radioactive material to tumor tissue while reducing radiation exposure to healthy tissue. Based on the above advantages, FL-091 labeled with imaging nuclide or therapeutic nuclide is expected to be used for precise imaging and treatment of targeted NTSR1, bringing new diagnosis and treatment methods to patients.

In this project, it is planned to use 68Ga and 111In to label FL-091 respectively for PET or SPECT imaging to initially evaluate the biodistribution of the probe in the human body, and diagnose and stage various malignant tumors including head and neck cancer, colorectal cancer and pancreatic adenocarcinoma. We will discuss the detection performance of 68Ga-FL-091 and 111In-FL-091 on malignant tumors, and lay the foundation for future use of therapeutic nuclide labeled FL-091 for nuclide targeted internal irradiation treatment of malignant tumors.

Inclusion Criteria:

Each subject must meet all enrollment criteria to be eligible to participate in the study:

1. The subject or his/her legal representative is able to sign and date the informed consent form;
2. A commitment to comply with the research procedures and to cooperate in the implementation of the full research process;
3. Adult patients or healthy volunteers (aged 18 or above) of either sex;
4. Patients with clinically suspected or confirmed malignant tumors such as head and neck cancer, colorectal cancer, or pancreatic cancer (supporting evidence includes serum-related tumor markers, imaging data such as ultrasound, CT, MRI, etc., and histological pathology examination, etc.) and in good general condition;
5. Consistent with the results of specific laboratory tests;
6. Females of childbearing potential who have been using contraception for at least one month prior to screening and who are committed to using contraception for the entire study period and until a specified time after the end of the study；
7. Other set entry criteria.

Exclusion Criteria:

All subjects who meet any of the exclusion criteria baseline will be excluded from the study:

1. Those who are unable to complete a PET/MR or PET/CT examination (including inability to lie down, claustrophobia, radiophobia, etc.);
2. Having other comorbidities;
3. Patients with known hypersensitivity to FL-091 fragment developers or synthetic excipients; fasting blood glucose level greater than 11.0 mmol/L prior to 18F-FDG injection；
4. Have a history of comorbid drug use;
5. Patients considered by the investigator to have poor compliance;
6. Patients during pregnancy or lactation;
7. Persons with other factors that make participation in this test inappropriate.

Patients with clinically suspected or confirmed malignant tumors such as head and neck cancer, colorectal cancer, or pancreatic cancer (supporting evidence includes serum-related tumor markers, imaging data such as ultrasound, CT, MRI, etc., and histological pathology examination, etc.) and in good general condition.