Clinical Study of Carbon Ion Radiotherapy for Pancreatic Cancer.

1.CIRT: GTV: Primary tumor visible on imaging and clinical examination, and involved regional lymph nodes identified by CT/MRI (≥1.0 cm) or PET/CT scan. CTV: GTV plus 5mm margin, include posterior peritoneal plexus area and elective node irradiation around the pancreas (ENI). PTV: CTV plus 2.5-5mm margin (depending on the system error of each unit; When pancreatic head cancer is close to the stomach and intestines, the gastrointestinal direction does not expand). ITV: delineated on 4D-CT considering the influence of respiratory activity. Prescription dose: Stratification by measuring the nearest distance between PTV and gastrointestinal tract (≥5mm or \< 5mm); Pancreatic head cancer (distance \< 5mm) : 52.8Gy(RBE)/4.4Gy/12Fx; Pancreatic head, body and tail cancer (≥5mm) : 57.2Gy(RBE)/4.4Gy/13Fx. CIRT was once a day, four or five times a week. 2.Chemotherapy:Gemcitabine 1000mg/m2, intravenous infusion, dl, d8; Q3w . 3.Targeted therapyNituzumab injection 400mg, Qw，at least 4-6 cycles.