The Bug in the Cancer Treatment Software

The software used to calculate the amount of radiation that cancer patients should receive in radiation therapy sessions. The therapists were meant to place metal shields on the patient to protect healthy tissue from radiation damage. If you drew the hole in one direction, you get the correct dose of radiation. But if you drew it in the other direction, so like clockwise versus counterclockwise, the software would recommend a dosage twice as strong as what was needed. Eight patients died as a result of this and another 20 received doses high enough to potentially cause health problems later on.