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Therac-25 Lawsuit for Victims Against the AECL

Therac-25 Lawsuit for Victims Against the AECL. Zeke Dunlap Quinncy Thomas Sterling Sanders. Therac-25 Victims. The Therac-25 software is directly to blame for the injures to six victims between 1985 and 1987.

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Therac-25 Lawsuit for Victims Against the AECL

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  1. Therac-25Lawsuit for Victims Against the AECL Zeke Dunlap Quinncy Thomas Sterling Sanders

  2. Therac-25 Victims • The Therac-25 software is directly to blame for the injures to six victims between 1985 and 1987. • The Atomic Energy of Canada Ltd. (AECL) carries the burden of blame for the massive overdoses of radiation that the Therac-25 gave to patients being treated by the software. • Three deaths were caused by this unimaginable lapse in judgment by the AECL.

  3. Whose to blame? • The AECL did not take the appropriate measures to insure that the Therac-25 would provide the utmost safety precautions for the patients who were being treated with the software. • Insufficient testing, numerous bugs, bad safety design, and poor programming techniques were all contributors to the incidents that injured patients who trusted the Therac-25.

  4. Design Flaws in the Therac-25 • The software developers were too cheap! The Therac-20 has independent protective circuits for monitoring electron-beam scanning, plus mechanical interlocks for policing the machine and ensuring safe operation. Too avoid extra expenses, AECL decided not to duplicate all the existing hardware safety mechanisms and interlocks. . • Error messages were not informing to the operators of the software. There were no definitions found in the manual that came with the Therac-25. • The Therac-25 basically had reused software. This was discovered when bugs found within the previous model of the Therac-20 was also found in the Therac-25..

  5. Bug in the Therac-25 • A major bug in the Therac-25 was an overflow error, which could have been prevented if careful design techniques would have been implemented. • The overflow error checked off that the system was ready to begin radiation, when the system was actually giving harmful doses of radiation to the patients.

  6. AECL’s Tenacity • The AECL repeatedly stated that there was no possibility of an overdose of radiation that could be caused by the software. • After the 2nd incident, the AECL told the FDA that the source of the problem could not be located, but the AECL publicly stated that the safety of the Therac-25 had been improved by 5 times after they implemented some safety features in reaction to the incident. • A Canadian agency urged the AECL to implement more safety features, but the AECL insisted that the software was now safe.

  7. Overconfidence • Some hospitals using the Therac-25 implemented their own safety mechanisms. Those hospitals never had a single overdose of radiation on any patients. • Other hospitals felt secure when the AECL told them it would be a waste of money to implement safety mechanisms because the software was safe.

  8. Conclusion • The AECL’s irresponsibility should not be overlooked. The victims of the Therac-25 should not be left without some retribution. • The AECL’s lack of emphasis on the safety of the software is extremely tragic in such a safety critical software system.

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