Radiotherapy, i.e. radiation therapy, is based on the principle of using X-rays to break the DNA of tumor cells to kill them, and plays an important role in all stages of comprehensive tumor treatment. When the first doctor of a tumor patient refers the patient to the radiotherapy department, our radiotherapist will make a comprehensive assessment of the patient, including not only the stage of the tumor, the general condition of the patient, but also the treatment and laboratory tests that the patient has received. In particular, we need to perform a layer-by-layer study of imaging (CT/MRI/PET, etc.) for the areas that require radiotherapy, so a mere phone call or consultation is basically a perfunctory and dismissive approach to treatment. After a thorough weighing of the best treatment options for the patient, we will also outline the target area and develop a physical plan for radiation therapy. So the patient will have to wait patiently for several days, and we will verify the positioning lines under the simulator before the actual treatment begins. So the positioning line is a prerequisite for treatment, so make sure you protect it!