Database of radiological incidents and related events--Johnston's Archive

Yakima radiotherapy accident, 1987

compiled by Wm. Robert Johnston
last modified 13 June 2004

Date: 17 January 1987

Location: Yakima Valley Memorial Hospital, Yakima, Washington, USA

Type of event: radiotherapy accident


A defect in the computer program controlling the Therac-25 radiation therapy accelerator resulted in overexposures to patients. A male patient was overexposed (estimated dose 8000-10000 rads localized), immediately reporting pain and developing skin burns later that day. The patient, although previously suffering from terminal cancer, died in April of complications related to the overexposure.

Consequences: 1 fatality.


© 2004 by Wm. Robert Johnston.
Last modified 13 June 2004.
Return to Home. Return to Nuclear Weapons Resources. Return to Database of radiological incidents and related events.