Date: 3 June 1985

Location: Kennestone Regional Oncology Center, Marietta, Georgia, USA

Type of event: radiotherapy accident

Description:

A defect in the computer program controlling the Therac-25 radiation therapy accelerator resulted in an overexposure to a patient. A 61-year old woman received a localized dose of 15,000 to 20,000 rads and immediately reported pain. Operators did not recognize the accident until the woman developed severe radiation burns later, eventually requiring removal of one breast and caused permanent impairment.

Consequences: 1 injury.

References:

• Leveson, Nancy, and Clark S. Turner, July 1993, "An investigation of the Therac-25 accidents," IEEE Computer, 26:18-41, on line at Computer Science at Virginia Tech [http://courses.cs.vt.edu/~cs3604/lib/Therac_25/Therac_1.html].

© 2004 by Wm. Robert Johnston.
Last modified 13 June 2004.
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