Radiotherapy does not shed hair if it is not applied to the scalp region. But if treatment is applied on the scalp hair, hair loss can be seen. Because radiotherapy is a local treatment method and its beneficial effect and side effect are only related to the region where the treatment is applied. Thus, for example, radiotherapy for lung tumors does not necessarily cause hair loss, but brain tumors can also cause hair loss in some of the head and neck tumors that hit the scalp. The shape and degree of hair loss varies according to the volume and total dose applied to radiotherapy. In cases where the entire brain is irradiated (brain metastasis), hair loss may occur in each region of the scalp. In cases where a region of the brain is irradiated (such as primary brain tumors, head and neck tumors), only that region is shed.
Hair loss seen on radiotherapy is often temporary, and after treatment the hair comes out again. Some brain tumors may require high doses of radiation and in these cases hair regrowth may be delayed or rarely ever occur. It is a common occurrence that the color and texture of the hair coming back after the radiotherapy changes from the original hair.

Radiotherapy can sometimes be administered concurrently with chemotherapy. Many drugs used in chemotherapy are likely to cause hair loss. In this case, it should be known that this effect is due to chemotherapy, it is not related to radiotherapy.