Therac-25: What happened?

• Normal radiation treatments: 6,000 rads over a 3 week period, under certain conditions Therac-25 was delivering 60,000 rads during one session.

Accidents

• 3 June 1985 – patient in Marietta GA received overdose

• 26 July 1985 – patient in Hamilton ONT severely burned.

Died November 1985

• December 1985 – patient in Yakima WA receives overdose

• 21 March 1986 – Tyler TX accident, patient died later

• 11 March 1986 – second T accident, patient died 1 month later

• 17 January 1987 – Second Yakima WA accident