There is no requirement of fasting for 3 hours when radiotherapy is performed for pancreatic cancer, but fasting is required when blood test is needed before radiotherapy. Radiotherapy is called radiation therapy in clinic, mainly used for the treatment of malignant tumors, this method is to use radiation to kill the local malignant tumor cells, so that the malignant tumors can be controlled. Radiation therapy is suitable for most malignant tumors. Before undergoing radiation therapy, patients usually do not have any special dietary requirements, and if they need to fast for three hours, the doctor will explain in advance. If the patient is combined with heart failure, acute inflammation should control the symptoms before radiation therapy. If you need to take blood tests before radiation therapy, you may be asked to fast before the test, you can consult the attending physician for specific requirements. Patients should seek medical advice in time after radiotherapy to avoid aggravation of the condition.