For 3 weeks, an extremely painful lesion had been present on the right ankle of a 46-year-old man. The 7 × 6-cm tender erosion was located just superior to the lateral malleolus. An antibiotic prescribed by another practitioner for a presumed infected insect bite had failed to ameliorate the pain and clear the lesion. In response to queries by Dr Ted Rosen of Houston, the patient disclosed that he was an industrial radiographer and had used a portable gammographic camera to check outdoor pipelines 1 month earlier. He had neglected to retract the radiation source (iridium 192) before placing the camera on his truck floor near his right ankle. A radiation burn, or acute radiodermatitis, was diagnosed. The patient was advised to keep the leg elevated and to use analgesics as necessary. An antibiotic ointment was prescribed as prophylaxis. The wound resolved in 3 months.