The CT Scanner Set Eight Times Too High

Between 2008 and 2009, a major medical center over-radiated 206 patients undergoing CT brain-perfusion scans for suspected stroke. An incorrect scanner protocol setting delivered up to about eight times the expected radiation dose. The error persisted for roughly 18 months and was discovered only when a patient reported hair loss.

FDA investigated and concluded the overexposures resulted from a misapplied console setting — a default / protocol value left wrong — not a scanner defect. It became the anchor case for FDA's Initiative to Reduce Unnecessary Radiation Exposure and the review expanded to other hospitals. (FDA, 2009–2010.)

1. A CT brain-perfusion protocol is configured on the scanner console.
2. A protocol / default setting is applied that delivers far more dose than intended.
3. Every subsequent stroke scan uses the same stored setting; the console shows a normal workflow.
4. About 40% of affected patients later experienced patchy hair loss.
5. The pattern surfaces only when a patient reports the hair loss, ~18 months in.

A landmark protocol error: 206 patients over-radiated at one center, 2008–2009; the review later expanded to about 385 patients across several hospitals. (FDA)

Up to ~8× the intended dose; about 40% of patients had hair loss. Shown through the CT gantry, the console protocol screen, and the empty scan room — never the patient.