I125 Seed Implantation vs Stereotactic Radiotherapy for Pancreatic Cancer

Inclusion Criteria: * Age: 18-80 years old; * Pathologically diagnosed pancreatic cancer patients;Follow-up treatment is in accordance with the NCCN2019 guidelines for standard treatment. * Clinical MDT discussion, for the unresectable locally advanced pancreatic cancer, AJCC version 8 pancreatic cancer stage T4N0M0 Arterial invasion: The pancreatic head and neck tumor invasion of pancreas superior mesenteric artery exceed 180 °;More than 180 ° celiac tumor invasion;The tumor invaded the first jejunal branch of the superior mesenteric artery.The pancreatic body tail superior mesenteric artery or celiac tumor invasion more than 180 °;The tumor invaded the abdominal trunk and abdominal aorta. Venous invasion: Tumor invasion or embolization (tumor thrombus or thrombus) of the head and neck of the pancreas leads to unresectable superior mesenteric vein or portal vein reconstruction;The tumor invaded the proximal end jejunal drainage branch of most superior mesenteric veins.The invasion or embolization of a tumor in the tail of the pancreas (thrombus or thrombus) leads to the unresectable reconstruction of the superior mesenteric vein or portal vein. * ECOG physical condition score: 0-1, Karnofsky score 60, able to withstand puncture; * Expected survival 3 months; * Good function of main organs, no severe hypertension, diabetes and heart disease. * Signed informed consent; * Has a good compliance, families agree to accept the survival follow-up. Exclusion Criteria: * Non-locally advanced pancreatic cancer. * Participated in other drug clinical trials within four weeks;There was a history of bleeding, and any bleeding event with severe grade of CTCAE5.0 or above occurred within 4 weeks before screening; * Screening of patients with known central nervous system metastasis or a history of central nervous system metastasis. * Patients with hypertension who cannot obtain good control by single antihypertensive drug treatment (systolic blood pressure \>140mmHg, diastolic blood pressure \>90mmHg);Having a history of unstable angina pectoris;Patients newly diagnosed with angina within 3 months before screening or myocardial infarction within 6 months before screening;Arrhythmia (including QTcF: 450ms in male and 470ms in female) requires long-term use of anti-arrhythmia drugs and New York heart association grade II cardiac dysfunction; * Long-term unhealed wounds or incomplete fracture healing; * Imaging showed that the tumor had invaded important blood vessels or the researchers judged that the patient's tumor had a very high possibility to invade important blood vessels during the treatment and cause fatal bleeding; * Coagulation function abnormalities, have bleeding tendency;Patients treated with anticoagulants or vitamin K antagonists such as warfarin, heparin or their analogues;The use of low-dose warfarin (1mg oral, once daily) or low-dose aspirin (no more than 100mg daily) for preventive purposes is permitted on the premise that the international standardized ratio of prothrombin time (INR) is 1.5; * Screening for the occurrence of hyperactive/venous thrombosis events in the first 6 months, such as cerebrovascular accidents (including temporary ischemic attack), deep vein thrombosis (except for venous thrombosis caused by intravenous catheterization in the early stage of chemotherapy, which was determined by the researchers to have recovered) and pulmonary embolism, etc. * Thyroid function was abnormal in the past and could not be kept within the normal range even in the case of drug treatment. * Attending has a history of psychotropic drug abuse, and can't attend or has mental disorder; * Always half a year after abdominal tumor lesion radiation; * Immunodeficiency disease, or has other acquired, congenital immunodeficiency disease, or has a history of organ transplantation; * Judgment according to the researchers, there is serious to endanger the safety of patients or patients completed the research associated with disease.