Hospital error leads to radiation overdoses

The article: http://www.latimes.com/news/local/la-me-cedars13-2009oct13,0,1200257.story

(…)
Doctors believed it would provide them more useful data to analyze disruptions in the flow of blood to brain tissue.
That meant resetting the machine to override the pre-programmed instructions that came with the scanner when it was installed.
“There was a misunderstanding about an embedded default setting applied by the machine . . . ,” officials at the renowned Los Angeles hospital said in a written statement that provided no other details about how the error occurred. “As a result, the use of this protocol resulted in a higher than expected amount of radiation.”
The dose of radiation was eight times what it should have been.
Once the scanner was programmed with the new instructions, the higher dose was essentially locked in. Each patient who got the procedure — known as a CT brain perfusion scan — was subjected to the overdose.
(…)
The machine was used for other types of scans but the reset error affected only the potential stroke patients, said Richard Elbaum, a hospital spokesman.
The error went unnoticed for the next 18 months, until this August, when a stroke patient informed the hospital that he had begun losing his hair after a scan.
When the hospital reviewed its records, it found — and contacted — 206 people who had received the overdoses to inform them of the mistake. Only then, Elbaum said, did the hospital learn that about 40% of them had suffered patchy hair loss. Many also experienced reddening of the skin.
(…)
General Electric, the manufacturer of the scanner, released its own statement Monday saying there were “no malfunctions or defects” of the machine.

I did a research over the web in blogs and forums about how this incident is seen. 

Yes, a few people blame hospital for not testing their programming.

OK, doctors are not programmers, but the programming language was, probably, of a high-level. Probably, quite simple to use, and, definitely, with an error-handling protecting the equipment.

Now, how could doctors conduct a professional testing?  Maybe, they did a few tests to confirm the code is doing what they wanted (collecting more data). But did they test that it’s not doing something else?..