On January 17, 1987, in Yakima Valley Memorial Hospital in Washington (now Virginia Mason Memorial), a patient was due to receive eighty-six rads from a Therac-25 machine (the rad is an antiquated unit of radiation absorption). Before the patient was to receive the dose of X-rays, however, the metal target and collimator had been moved out of the way so the machine could be aligned using normal visible light. They were not put back.
Gaaaaah
