Are there any prior cases of radiation exposure due to a medical accident?

There were many cases of excessively high or low irradiation during radiotherapy in the first half of 2000. These cases occurred between 2001 and 2004 at seven facilities within Japan, involving a total of 481 patients. At six of those facilities, the accidents were caused by simple mistakes, such as data entry errors, whereas the accident at one facility was caused by a communication error between the radiological technologist and medical practitioner in charge of radiotherapy. Also, a famous nuclear medicine accident occurred in 2011, where it was discovered that a large quantity of a radioactive drug for nuclear medicine had been administered to an infant. Though the case involved a nuclear medicine scan, the dose to the organ targeted by the examination had reached a maximum of 4 grays. Fortunately, no damage occurred, but the accident was caused by inadequate study by the radiological technologist and poor communication within the facility. In terms of CT scan accidents, the case that should be remembered is the case of hair loss during a perfusion examination. Recent CT systems are capable of higher output levels, which means there is an increased risk of irradiating patients with high dose levels due to an operating error.