The main purpose of this study is to evaluate the effectiveness of technetium [99mTc]-H7ND injection in the diagnosis of peritoneal metastasis of gastrointestinal malignant tumor. Objective: To evaluate the safety of technetium [99mTc]-H7ND injection in the diagnosis of peritoneal metastasis of gastrointestinal malignant tumor. Objective: To explore the diagnostic threshold of technetium [99mTc]-H7ND injection for peritoneal metastasis of gastrointestinal malignant tumor.

Inclusion Criteria:

Only those who meet all the following requirements are eligible to join the group:

1. Adults over 18 years of age (based on the time when the informed consent form was signed) can be male or female;
2. Subjects with gastrointestinal malignant tumor confirmed by histology/cytology;
3. Subjects to be surgically removed or explored;
4. The estimated survival time is ≥12 weeks;
5. Subjects of childbearing age agreed to adopt effective contraceptive measures during the study period;
6. Subjects fully understand the purpose, nature, methods and possible adverse reactions of the experiment, voluntarily participate in and sign a written informed consent, and are willing to follow the requirements of the protocol to complete the study.riteria:

Those who meet one of the following items are not allowed to join the group:

1. According to the researcher's judgment, during the screening period, from the imaging examination to the comprehensive real diagnosis information result, the patients were treated with anti-digestive tract tumor;
2. symptomatic brain metastases who need treatment;
3. Have serious cardiovascular and cerebrovascular diseases;
4. There are other contraindications for imaging examination of the research plan, such as claustrophobia;
5. Have a history of other malignant tumors;
6. Pregnant (pregnancy test positive in screening period) or lactating women;
7. Other circumstances that the researcher considers inappropriate to participate in this clinical trial.