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

Zaragoza radiotherapy accident, 1990

compiled by Wm. Robert Johnston
last modified 26 October 2008

Date: 10-20 December 1990

Location: Zaragoza Clinical University, Zaragoza, Spain

Type of event: radiotherapy accident


An error occurred in the maintenance and calibration of a linear accelerator used for clinical radiotherapy; combined with procedural violations, overdosages of 200-700% occurred. The accelerator is related to the Therac-25 involved in several accidents in the United States and Canada. A total of 27 patients were overexposed during treatments for tumors between 10 and 20 December. Signs of radiation injury were observed on 26 December, and the first death occurred possibly shortly thereafter. By 28 February 1991 three patients had died, and an additional 7 died by 31 March 1991. Spainish authorities were reportly hesitant to release details of the accident, but sought foreign assistance in early 1991. A total of 18 eventually died as a result of radiation overexposures. The remaining patients all suffered major disabilities as a result.

Consequences: 18 fatalities, 9 injuries.


© 2004, 2005, 2008 by Wm. Robert Johnston.
Last modified 26 October 2008.
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