8.4.1 Acute Radiotherapy Response
（1）Radioactive dermatitis
At 3～4 weeks of radiotherapy，the skin may have radioactive dry skin reactions such as pigmentation，hair follicle dilation，hair loss，erythema，edema，etc.；blistering，ulceration，etc.may occur on the 5th week after radiotherapy or 1～2 weeks after radiotherapy.The skin folds will be heavier，such as the chest wall near the armpit，the underlying breast folds，and the skin folds on the collarbone.When positioning，try to make the skin fold flat.The close-fitting clothes are soft and breathable during treatment，keeping the skin of the exposed field dry and clean.Do not use tape，alcohol，plaster，etc.in the skin of the field.When a wet skin reaction occurs，the local anti-inflammatory and swelling drug can be applied wet to avoid infection，and it usually heals in 2-3 weeks.
（2）Breast edema pain
After breast-conserving surgery，patients with whole breast radiotherapy may have breast edema pain in the late stage of radiotherapy and after the end of radiotherapy，especially in large breasts.When the patient takes a bath to wash the skin of the breast，it can aggravate the edema.Therefore，the patient should avoid squatting.Lighter need not be treated，severe cases can be treated with pain relief，or shortterm hormone swelling treatment.(https://www.daowen.com)
（3）radiation pneumonitis
Most of them appear within 1 to 6 months after the end of radiotherapy，and very few appear in radiotherapy.The chest radiograph or chest ct shows a patch of lung exudation consistent with the radiotherapy field.Most patients are asymptomatic or have a dry cough，shortness of breath or fever.The incidence of symptomatic radiation pneumonitis is low，about 0～10%，mostly grade 2，and grades 4～5 are rare.
（4）Systemic response
Postoperative radiotherapy in breast cancer patients has little effect on blood.Patients after chemotherapy may have mild leukopenia during radiotherapy，and more dietary conditioning or Chinese medicine blood treatment.Fatigue is more common during radiotherapy，and it can be used to support the treatment.