A keloid, commonly known as a scar, is an overgrown abnormal scar tissue formed after a healing skin wound or an unexplained skin injury has healed. The current academic opinion is that keloid scars can be diagnosed if they have the following characteristics: (1) lesions that exceed the original skin injury; (2) persistent growth; and (3) nodular, striated, or lamellar masses that are hard and reddish in color, rising above the skin surface. It is also called connective tissue hyperplasia, and in Chinese medicine it is called crabfoot swelling or giant scarring, which is a benign lump of varying shapes, redness and hardness that rises out of normal skin. The clinical manifestations of keloid scars can be broadly divided into two categories: primary and secondary. Primary keloids, mostly on the front of the chest or behind the shoulders, start as small red dots with itching and gradually change from small to large, from soft to hard, red or dark red, with cords, butterflies, rounds, irregular shapes, etc. Secondary keloids are also called hyperplastic keloids, which are also divided into: acne keloids and keloid cancer. Most of them are caused by burns, trauma, acne, infection and pus, or after surgery, laser, freezing, skin implant, or hormonal drugs, which can cause excessive proliferation of damaged tissues and degeneration of subcutaneous tissues, protruding from the skin, red or dark red with itching or stinging, and some of them have obvious capillaries extending outward. Definition of keloid: It is the result of excessive proliferation of collagen fibers, also known as connective tissue hyperplasia, which is a benign lump of varying shapes, redness and hardness in the healing process of skin injury, and is also called crabfoot swelling or giant scar. Second, the status of scar treatment: there are many scar treatment methods, such as pressure bandaging, application of corticosteroids and silicone, laser and cryotherapy. However, the effect is poor. At present, surgery combined with postoperative radiotherapy is recognized as the best treatment method. Third, the mechanism of postoperative radiotherapy: the naive fibroblasts at the incision around 24 hours after keloid surgery account for the majority, and unstable collagen fibers are the main component, which are more sensitive to radiation, and radiotherapy is most suitable during this period. At the same time, radiation can effectively inhibit the proliferation of this cell, inhibit capillary proliferation at the incision site, and bring the collagen fiber metabolism at the incision site to a relative balance. At the same time, radiotherapy also has a certain role in hemostasis and anti-infection. Fourth, postoperative radiotherapy method: ? Radiotherapy time: about 24 hours after surgery? Radiation used: 6~7 MeV electron beam? Dose of radiation: 9Gy each time, two times, one week between treatments? Radiation range: including the stitches of the surgical suture, with the peripheral expansion of 3-5 mm. after the skin grafting surgery, only the peripheral suture area of the skin graft will be irradiated. V. Precautions during radiotherapy: ① The medication must be changed after each radiotherapy; ② Do not scrub the irradiated area. Recurrence: According to the principle of radiobiology, scar tissue is different from malignant tumor and is slightly less sensitive to radiotherapy, so large split dose treatment is more effective. Patients are recommended to come to our radiotherapy department for review in six months or a year after treatment.