When vessels are exposed to ionising radiation experimentally there is immediate damage to the endothelium, with increased permeability and necrosis followed by healing with intimal proliferation and vascular stenoses. Smooth muscle cells undergo more subtle damage resulting in loss of cellularity of the media and replacement by fibrosis. Radiation also induces a chronic antiangiogenic effect and contributes to growth abnormality, for example, in limb development [1, 2]. In man, long-term complications of radiation injury are still commonly seen despite advances in radiotherapy. Acute effects are largely time dependent and can be controlled by alteration of therapy schedule. For chronic changes, the age at the time of exposure to radiation does not seem to affect the time of the onset of lesions. No direct correlation has been established between the severity of the injury and the dose of radiation and the true incidence of radiation-induced vascular changes is almost certainly underestimated. The duration of time between exposure and development of post-radiation changes varies from months to 24 years, with a mean of 14 years [3–7], and further complications (tissue necrosis, infection, and ulceration) may occur later. The clinical patterns depend on the role of the organ system involved, and ischaemic syndomes, erectile dysfunction [8], aortic arch syndrome or pulseless disease [9], aneurysms, veno-occlusive liver disease [10] and vascular rupture [11] have all been reported. In children, moyamoya syndrome has been reported following radiation therapy for tumours at the base of the brain [12].