Inclusion Criteria:  Aged 18-75 years Histologically or cytologically confirmed mediastinal cancer Patients with inoperable mediastinal lesions Eastern Cooperative Oncology Group (ECOG) performance status 0-1 Normal function of organs and bone marrow within 14 days: Total bilirubin 1.5 times or less the upper limits of normal (ULN); AST and ALT 1.5 times or less the ULN; absolute neutrophil count≥ 500 cells/mm3; creatinine clearance rate(CCR) ≥45 mL/min; Platelet count≥50,000 cells/mm3; international normalized ratio(INR) ≤1.5#Prothrombin Time (PT)≤ 1.5 × ULN Informed-consent  Exclusion Criteria:  Patients with contraindications for MRI Previous radiotherapy or excision for mediastinal tumor The tumor has completely approached, encircled, or invaded the intravascular space of the great vessels (e.g., the pulmonary artery or the superior vena cava) A cavity over 2cm in diameter of primary tumor or metastasis Bleeding tendency or coagulation disorder Hemoptysis (1/2 teaspoon blood/day) happened within 1 month The use of full-dose anticoagulation within the past 1 month Severe vascular disease occurred within 6 months Gastrointestinal fistula, perforation or abdominal abscess occurred within 6 months Hypertensive crisis, hypertensive encephalopathy, symptomatic heart failure (New York class II or above), active cerebrovascular disease or cardiovascular disease occurred within 6 months Uncontrolled hypertension (systolic > 150mmHg and/or diastolic > 100mmHg) Major surgery within 28 days or minor surgery or needle biopsy within 48 hours Urine protein 3-4+, or 24h urine protein quantitative >1g Severe uncontrolled disease Uncontrollable seizure or psychotic patients without self-control ability Women in pregnancy, lactation period Other not suitable conditions determined by the investigators