**3.3 Cerebral infarction**

Occlusion of the carotid artery or its branches leading to cerebral infarction or ischemic stroke is a potentially serious and life-threatening complication after stereotactic radiation therapy involving the extra- or intracavernous portion of the carotid artery or the Circle of Willis [67]. Although considered to be relatively rare, radiation-induced cerebral infarction has been reported after single fraction stereotactic radiosurgery or radiation therapy of meningiomas, pituitary adenomas, craniopharyngiomas, and vestibular schwannomas, with an occurrence of 1–7% [24, 46, 68–70]. However, the risk of cerebral infarction may not be increased when compared with the incidence in the general population. Predisposing risk factors identified for ischemic events are smoking, hypertension, and hyperlipidemia, as well as increased age [70]. Cerebral infarction is by definition a clinical diagnosis; therefore, subclinical infarctions only detectable by neuroimaging may occur [70].
