Scores of radiation overdoses at a medical center have been traced to a single cause. That cause is a hospital mistake made when resetting a CT scanner. Hospital officials said that the medical error occurred in February 2008, when the hospital began using a new protocol for a specialized type of scan used to diagnose strokes. The doctors had believed it would provide them more useful data to analyze disruptions in the flow of blood to brain tissue. However this meant resetting the machine to override the pre-programmed instructions that came with the scanner when it was installed. There turned out to be a misunderstanding about an embedded default setting applied by the machine and as a result there were higher levels of radiation administered to patients. The dose of radiation was eight times what it should have been. Once the scanner was programmed each patient received the overdose. The hospital error went unnoticed for the next 18 months, when a stroke patient informed the hospital that he had begun using his hair after a scan. 206 people had received the overdoses and 40% of them had suffered patchy hair loss. Excess radiation would be difficult to detect from simply looking at the scan results. Radiation exposure increases the likelihood of cancer. To read more about the radiation overdoses, please click the link.