A patient with a large left-sided arteriovenous malformation underwent superselective angiography and therapeutic embolization. Sixteen days later he presented with an acute anagen-dystrophic hair loss localized to the occipital and right parietal regions corresponding to the irradiated scalp area. The diagnosis of an acute radiation injury to the hair follicle from prolonged fluoroscopic imaging during the interventional neuroradiologic procedure was made. This reversible side effect occurs typically after single short-term exposures of 300-400 cGy. Above single doses of 1200 cGy, the epilation is permanent. Patients have to be informed about the possibility of this reversible complication, which must be distinguished from alopecia areata, postoperative ischemic pressure alopecia and drug toxicity.