Radiotherapy for pancreatic cancer The pancreatic gland is anatomically located deep in the body and has no obvious symptoms in the early stage, and the disease is mostly in the middle and late stage when it is detected. Surgery is the treatment of choice for hepatocellular carcinoma, but only 5-22% of patients have resectable tumors. The 5-year survival rate of radical surgery (complete resection) is only 12-24%, and the prognosis of palliative surgery (incomplete resection) is even worse, with a general survival period of only 5-7 months. Treatment of postoperative residual, recurrent and inoperable patients is therefore particularly important, as greater than 80% of pancreatic cancer patients die from uncontrolled localization. Adjuvant radiotherapy has the effect of relieving symptoms and prolonging patient survival, but the effect of radiotherapy is limited by the dose of radiotherapy. Conventional radiotherapy includes more normal tissues, such as liver, stomach, small intestine, kidney and spinal cord, and the dose of radiotherapy is generally less than 45Gy, which is far below the radical dose for pancreatic cancer cells and cannot achieve complete tumor control. Image guided 3D conformal intensity modulated radiotherapy, which focuses the radiation geometrically on the focal area and sharply reduces the dose to the surrounding normal tissues, can achieve tumor control without causing significant damage to the surrounding normal tissues; at the same time, due to the higher fractionated dose, the biological dose increases significantly and the killing effect on tumor cells increases exponentially, thus making it possible for radiotherapy to cure pancreatic cancer radically. In addition, the scope of treatment can be consistent with the shape of the tumor in three dimensions, which reduces the irradiation of normal tissues and significantly reduces the damage to normal tissues. The indications are as follows: 1.Surgical treatment is feasible, but combined with contraindications to surgery and cannot tolerate surgery or anesthesia or the patient refuses surgery. 2.Patients with late local tumor that cannot be removed. Most of the tumors are found to be advanced and lose the opportunity of surgery; however, 40% of them are still in the local area without extensive metastasis, which are the indications for 3D conformal intensity modulated radiotherapy. Complete surgical resection is very important for patient survival. The 5-year survival rate for radical surgery (complete resection) is only 12-24%, and the prognosis for palliative surgery (incomplete resection) is even worse, with a typical survival period of only 5-7 months. Therefore, for patients who cannot be operated, 3D conformal intensity-modulated radiotherapy becomes a better choice for these patients, and the average survival can be extended by one time. The higher the dose of local radiotherapy, the longer the survival period, therefore, it is recommended to give high dose of DT60-70Gy. The study of John Hopkins Medical School found that the survival of patients with radical resection of pancreatic cancer can be prolonged by nearly 1 times if radiotherapy is given after surgery, thus post-operative radiotherapy has become a routine treatment for pancreatic cancer. 4. Palliative treatment is mainly aimed at relieving patients’ pain and prolonging their survival. These include: 1) single or multiple metastases of the pancreas from other tumors, 2) distant metastases from pancreatic cancer, 3) late localized tumors, and relief of pain, pressure, obstruction, jaundice, and poor circulation.