Date: 22 August-27 September 1996

Location: San Jose, Costa Rica

Type of event: radiotherapy accident

Description:

An error in the calibration of a cobalt-60 radiotherapy unit in Costa Rica resulted in overdosages of about 60%. The equipment change that produced the error occurred on 22 August, with the first treatments administered on 26 August. Of 42 patients that died through 7 July 1997, 3 died probably as a direct result of radiation exposure and 4 more with radiation exposure a contributing cause. Another 22 died probably of their disease and not of radiation exposure. Of the surviving overexposed patients, 4 suffered "catastrophic" consequences, 16 more severe effects, 26 had lesser effects, and 22 had no effects. Some sources attribute 17 deaths to the misadministrations.

Consequences: 7 fatalities, 81 injuries.

References:

• IAEA, June 1998, Accidental Overexposure of Radiotherapy Patients in San Jose, Costa Rica, IAEA (Vienna, Austria), on line at IAEA [http://www-pub.iaea.org/MTCD/publications/PDF/P027_scr.pdf].
• Ortiz, P., M. Oresegun, and J. Wheatley, 2000, "Lessons from major radiation accidents," on line, International Radiation Protection Association [http://www.irpa.net/irpa10/cdrom/00140.pdf].

© 2004, 2005 by Wm. Robert Johnston.
Last modified 11 May 2005.
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