Brain

See Cranial Radiation Therapy and Neurotoxicity

Heart and blood vessels

Chest pain, radiation pericarditis, radiation myocarditis

Skin

Dose 2–4 Gy: Transient erythema

Dose 4–5 Gy: Transient erythema, temporary epilation (within 2–3 weeks of exposure to > ~ 4 Gy)

Dose 5–10 Gy: Prolonged erythema, possibly permanent epilation, dry desquamation (with exposures at the high end of the range)

Dose 10–15 Gy: Dry desquamation (within 2–8 weeks of exposure)

Dose 15–20 Gy: Moist desquamation (within 2–4 weeks of exposure)

Dose 15–25 Gy: Blister formation (within 2–3 weeks of exposure)

Dose > 20 Gy: Ulceration (within 2–3 weeks of exposure)

Dose > 25 Gy: Necrosis (> 3 weeks after exposure)

Gonads

Depressed spermatogenesis, amenorrhea, decreased libido

Threshold dose (~1% incidence) for sterility:

• Testes: > 6 Gy, onset ~ 3 weeks

• Ovaries: > 3 Gy, onset < 1 week

Head and neck

Mucositis, odynophagia, thyroid carcinoma

Muscle and bone

Myopathy, neoplastic changes, osteosarcoma

Eyes

Dose > ~ 0.5 Gy: Cataracts (after ~ 20 years latent period; the higher the dose and the younger the age at exposure, the shorter the latent period)

Lungs

Acute pneumonitis

Fractionated exposure>30 Gy: Sometimes fatal (LD-50 ~ >10 Gy single high-dose exposure)

Pulmonary fibrosis

Kidneys

Decreased GFR, decreased renal tubular function

High doses (after 6 months–1 year latent period): Proteinuria, renal insufficiency, anemia, hypertension

Cumulative dose > 20 Gy in < 5 weeks: Radiation fibrosis, oliguric renal failure

Spinal cord

Dose > 50 Gy: Myelopathy

Fetus

Growth restriction, congenital malformations, in-born errors of metabolism, fetal death

Dose < 0.1 Gy: No significant effect

Future cancer risk about the same as exposure of a child: ~ 10–15% per Gy