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An Investigation of Therac-25 Accidents - I
Computers are increasingly being introduced into safety-critical systems and, as a consequence, have been involved in accidents. Some of the most widely cited software-related accidents in safety-critical systems involved a computerized radiation therapy machine called the Therac-25. Between June 1985 and January 1987, six known accidents involved massive overdoses by the Therac-25 -- with resultant deaths and serious injuries. They have been described as the worst series of radiation accidents in the 35-year history of medical accelerators.[1]
With information for this article taken from publicly available documents, we present a detailed accident investigation of the factors involved in the overdoses and the attempts by the users, manufacturers, and the US and Canadian governments to deal with them. Our goal is to help others learn from this experience, not to criticize the equipment's manufacturer or anyone else. The mistakes that were made are not unique to this manufacturer but are, unfortunately, fairly common in other safety-critical systems. As Frank Houston of the US Food and Drug Administration (FDA) said, "A significant amount of software for life-critical systems comes from small firms, especially in the medical device industry; firms that fit the profile of those resistant to or uninformed of the principles of either system safety or software engineering."[2] -
Therac-25 - Wikipedia, the free encyclopedia
The Therac-25 was a radiation therapy machine produced by Atomic Energy of Canada Limited (AECL) after the Therac-6 and Therac-20 units (the earlier units had been produced in partnership with CGR of France).
Therac 25 user interface [1]
PATIENT NAME : JOHN DOE
TREATMENT MODE : FIX BEAM TYPE: X ENERGY (MeV): 25
ACTUAL PRESCRIBED
UNIT RATE/MINUTE 0 200
MONITOR UNITS 50 50 200
TIME (MIN) 0.27 1.00
GANTRY ROTATION (DEG) 0.0 0 VERIFIED
COLLIMATOR ROTATION (DEG) 359.2 359 VERIFIED
COLLIMATOR X (CM) 14.2 14.3 VERIFIED
COLLIMATOR Y (CM) 27.2 27.3 VERIFIED
WEDGE NUMBER 1 1 VERIFIED
ACCESSORY NUMBER 0 0 VERIFIED
DATE : 84-OCT-26 SYSTEM : BEAM READY OP.MODE: TREAT AUTO
TIME : 12:55. 8 TREAT : TREAT PAUSE X-RAY 173777
OPR ID : T25VO2-RO3 REASON : OPERATOR COMMAND:
It was involved in at least six accidents between 1985 and 1987, in which patients were given massive overdoses of radiation, -
Phone 'Rootkit' Maker Carrier IQ May Have Violated Wiretap Law In Millions Of Cases - Forbes
Update 2: Class action lawsuits have now been filed against Carrier IQ, HTC, and Samsung.
A piece of keystroke-sniffing software called Carrier IQ has been embedded so deeply in millions of HTC and Samsung-built Android devices that it’s tough to spot and nearly impossible to remove, as 25-year old Connecticut systems administrator Trevor Eckhart revealed in a video Tuesday.
Here's The Letter Senator Al Franken Just Sent To Phone 'Rootkit' Firm Carrier IQ
Andy Greenberg
Forbes Staff
That’s not just creepy, says Paul Ohm, a former Justice Department prosecutor and law professor at the University of Colorado Law School. He thinks it’s also likely grounds for a class action lawsuit based on a federal wiretapping law. -
SAP Deal Shows Rise of Online Software - WSJ.com
SAP AG's $3.4 billion agreement to acquire SuccessFactors Inc. shows just how big a threat online products are becoming to the kings of conventional software, and points to the possibility of more such acquisitions.
The deal, announced Saturday, should bolster SAP's portfolio of Web-based software. The urgency SAP felt to do that, industry watchers said, was apparent in the 52% premium the German software giant agreed to pay for the relatively small Silicon Valley company. -
Don’t Blame The IQ, Blame The Carrier | TechCrunch
You couldn’t swing a cat this week without hitting a story about Carrier IQ, which (if you have somehow avoided this information) is a bit of software installed on millions of phones that has access to a huge amount of user data. As developers hinted for months and eventually proved on camera, the software is aware of SMS content, secure web traffic, contacts, key presses, and more.
Monday, December 5, 2011
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