Frequencies considered especially dangerous occur where the human body can become resonant, at 35 MHz, 70 MHz, 80-100 MHz, 400 MHz, and 1 GHz. Exposure to microwaves of too high intensity can cause microwave burns. Types
Radiation dermatitis (also known as radiodermatitis) is a skin disease associated with prolonged exposure to ionizing radiation. : 131–2  Radiation dermatitis occurs to some degree in most patients receiving radiation therapy, with or without chemotherapy.There are three specific types of radiodermatitis: acute radiodermatitis, chronic radiodermatitis, and eosinophilic, polymorphic, and pruritic eruption associated with radiotherapy. : 39–40  Radiation therapy can also cause radiation cancer. : 40 With interventional fluoroscopy, because of the high skin doses that can be generated in the course of the intervention, some procedures have resulted in early (less than two months after exposure) and/or late (two months or more after exposure) skin reactions, including necrosis in some cases. : 773 Radiation dermatitis, in the form of intense erythema and vesiculation of the skin, may be observed in radiation ports. : 131 As many as 95% of patients treated with radiation therapy for cancer will experience a skin reaction. Some reactions are immediate, while others may be later (e.g., months after treatment). Acute
Acute radiodermatitis occurs when an "erythema dose" of ionizing radiation is given to the skin, after which visible erythema appears up to 24 hours after. : 39   Radiation dermatitis generally manifests within a few weeks after the start of radiotherapy. : 143   Acute radiodermatitis, while presenting as red patches, may sometimes also present with desquamation or blistering.
Nuclear accidents
Beta burns were a serious medical issue for some victims of the Chernobyl disaster; from 115 patients treated in Moscow, 30% had burns covering 10–50% of body surface, 11% were affected on 50–100% of skin; the massive exposure was often caused by clothes drenched with radioactive water. Some firefighters developed beta burns of lungs and nasopharyngeal region after inhalation of massive amounts of radioactive smoke. Out of 28 deaths, 16 had skin injuries listed among the causes. The beta activity was extremely high, with beta/gamma ratio reaching 10–30 and beta energy high enough to damage basal layer of the skin, resulting in large area portals for infections, exacerbated by damage to bone marrow and weakened immune system. Some patients received skin dose of 400–500 Gy. The infections caused more than half of the acute deaths. Several died of fourth degree beta burns between 9–28 days after dose of 6–16 Gy. Seven died after dose of 4–6 Gy and third degree beta burns in 4–6 weeks. One died later from second degree beta burns and dose 1-4 Gy. The survivors have atrophied skin which is spider veined and with underlying fibrosis.The burns may manifest at different times at different body areas. The Chernobyl liquidators burns first appeared on wrists, face, neck and feet, followed by chest and back, then by knees, hips and buttocks.Industrial radiography sources are a common source of beta burns in workers. Radiation therapy sources can cause beta burns during exposure of the patients.