When many people enter the radiotherapy department, they often find that many patients have a red mark on their face, which looks very scary. In fact, the red marks on the face are skin ink, which is used to determine the target area of radiotherapy, and the red box range is the area of head and neck tumors to be radiotherapy. The patients who are a little bit more sophisticated are very shy after drawing the marks on their faces, fearing that they will meet acquaintances, and some of them will even wash off the red marks secretly before going out, which will bring a lot of trouble to the doctor’s treatment. However, when we go to the radiotherapy department now, we cannot see which patient has a red mark on his face. How to determine the target area without the red marks? In the past, radiotherapists used to conduct treatment according to the marking line drawn by doctors. For example, the mark for nasopharyngeal cancer was drawn on both sides of the face, and the patient would lie on the treatment bed on the left side or the right side with soft pillows on the head and neck, and the radiotherapist would position the patient according to the marking line with a piece of lead. But this has great disadvantages, first of all, the repeatability of the patient’s position is poor, the patient’s body slightly leaning forward or pillow a little bit of activity will deviate greatly from the irradiation range. Secondly, the marking line on the face is easy to fall off, and once it falls off and is redrawn, there will be a certain error with the last line. It is because of these two reasons that radiotherapy can be deviated. As the saying goes, a miss is a miss. It may result in the tumor not needing to be treated with enough dose while the normal tissues will receive too much radiotherapy dose, which may even lead to recurrence of the tumor. Nowadays, patients with head and neck radiotherapy are mostly immobilized by masks and foam pillows, with the radiotherapy markers sitting on the masks, and with the use of low-melting-point lead to determine the target area, the face should no longer be painted with red frames. However, the purpose of this is not to “look good”, but for the precision of the treatment. The procedure is as follows: the patient’s head and neck are immobilized with a hydrolyzed plastic mask, films are taken under a simulator, and the target area is determined by consultation between the director, the professor, and the attending physician. Of course the target zone is drawn on the localization film and not on the face. According to the target area outlined in the localization film, a lead mold is made in the model room or an MLP is made in the physics room, and the final verification is done before radiotherapy is given. Now every time when radiotherapy is performed, the patient is placed in a supine position and the head of the radiotherapy machine is rotated to perform radiotherapy at different angles and locations. This ensures that the target area of each radiotherapy is very reproducible, i.e., the exact same site is treated each time. Now, based on this technology, our Radiotherapy Department has widely developed precise treatment techniques such as 3D conformal radiotherapy and intensity-modulated radiotherapy for the head and neck. It is believed that more new technologies will be applied in the clinic to serve the patients.