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Therac-25 Case

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Aliases in Therac-25

This case is a report of a real occurrence that we have documented to the best of our ability. None of the individuals in the case were fictional. None of the individuals were composites. We have attempted to verify the truth of all the events we have reported.

However, we have used aliases in this case because the purpose of our presentation is not to blame individuals, but to see the ethical and social issues that surround the design, manufacture, and use of computing systems in the real world.

We have not attempted to hide the identity of some organizations that were widely known (e.g. the Food and Drug Administration). Therac-25 is the real name of the machine involved in this case, and we felt it useless to change that name for presentation of the case. But we have attempted to provide a modicum of anonymity to others involved.

For those who require the real names involved in this case, we offer the following key

Real Name


Katy Yarbrough

Linda Knight (Injured June 3, 1985)

Frances Hill

Donna Gartner (Injured July 26, 1985)

Not disclosed

Janis Tilman (Injured Dec. 1985)

Voyne Ray Cox

Isaac Dahl (Injured March 22, 1986)

Verdon Kidd

Daniel McCarthy (Injured April 11, 1986)

Glen Dodd

Anders Engman (Injured Jan. 17, 1987)

Theratronics (private company resulting from spin-off of AECL Medical, then purchased by MDS Nordion)