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CT Scan "Reset Error" Gives 206 Patients Radiation Overdose
jeffb (2.718) writes "As the LA Times reports, 206 patients receiving CT scans at Cedar Sinai hospital received up to eight times the X-ray exposure doctors intended. (The FDA alert gives details about the doses involved.) A misunderstanding over an 'embedded default setting' appears to have led to the error, which occurred when the hospital 'began using a new protocol for a specialized type of scan used to diagnose strokes. Doctors believed it would provide them more useful data to analyze disruptions in the flow of blood to brain tissue.' Human-computer interaction classes from the late 1980s onward have pounded home the lesson of the Therac-25, the usability issues of which led to multiple deaths. Will we ever learn enough to make these errors truly uncommittable?"
As long as people are involved in some way, no.
Requiring that doctors RTFM is the first step.
The default setting for an equipment that can be lethal should be "Emit zero radiation". Then for each exposure, set the level of radiation you intend to use. This way, you ALWAYS KNOW the level of radiation the equipment will emit.
Better investigate "Hey, we got no picture" than "Hey, we got pictures, but everyone dies after that..."
Didn't RTFA.
Anyone else read this as David Banner?
Along with the usability issues with the design of the Therac-25 it's obvious that the attitude of the medical staff contributed greatly to the problem. Patients complained of being burned, but their complaints were essentially ignored. Meanwhile, they were sent back for multiple treatments. Overwhelming evidence of radiation burns was ignored or given only cursory investigation because medical personal or manufacturer reps claimed that it was impossible for the Therac-25 to be responsible for the burns.
There is and never will be such a thing as a machine without the possibility for error. And you'll never get around the old adage/rule - If it can happen, it will. How often it occurs it the key; and while we should always aim to make an error-less machine, it is an impossibility and we can only achieve it by make the occurrence of such errors as few and far between as possible.
After all, an error-prone human must be involved to make the machine; even if that machine made another machine a human was still involved at some point to make the original. Thus there will always be the possibility for errors. Even if, as demonstrated by the Matrix, iRobot, and many others, the machines make that error on purpose to save humanity - it is still an error.
Truth is like the sun. You can shut it out for a time, but it ain't goin' away. - Elvis Presley (source: imdb.com)
Will we ever learn enough to make these errors truly uncommittable?"
No. As long as correctness can't be proven and operators are permitted to create unanalyzed conditions by altering protocols there will always be risk. There are probably other mis-configured CT scanners out there in use right now that have been overdosing patients for years.
CT scans use X-rays; an easily detected frequency of light. Why not require that scanners incorporate an independent detector that measures the amount X-ray energy? If that is possible then create an interlock that can shut down the emitter when the net energy gets out of bounds and require that any such incident be NRC reportable. If the detector excluded from alteration by the operators then software bugs, misunderstandings, etc. can be detected even years after the last engineer had contact with the system, either before harm is done or at least before hundreds of patients are literally burned.
Lurking at the bottom of the gravity well, getting old
'How hard would it have been to stick a dosimeter in the machine after the change and run it though a test'
Supposedly the actual dose would have been displayed on the machine's screen (I wonder how prominently?):
http://www.latimes.com/news/local/la-me-cedars-sinai14-2009oct14,0,5065886.story
'"It's in your face on the screen," said Dr. Donald Rucker, chief medical officer for Siemens, a manufacturer of CT scanners.'
'CT technicians are trained to monitor dose levels, and some hospitals conduct checks before every scan..."There are other places where the techs might be operating more as button-pushers," said Dr. Geoffrey Rubin, a professor of radiology at Stanford University. "The user becomes a little blind to these numbers."'
Comment removed based on user account deletion
The advantages of simplified training are not just beneficial on an economic scale. While its unfortunate that this error killed people, think of how many more people would die if complex training was required to use these types of machines. Ultimately, it would lead to fewer operators and thus less access to the machine, which ostensibly helps save lives.
Monstar L
I don't think being trained to fully understand the automobile will decrease the number of automobile related deaths.
Being trained to fully understand the laws of physics would certainly decrease automobile accidents.
"chemo" refers to chemotherapy, where the patient is poisoned in the hopes that the poison will kill the cancer faster than it kills the patient. It is a different form of therapy than radiation therapy, in which the patient is subjected to intense doses of radiation in the hopes that the radiation will kill the cancer faster than it kills the patient. Often, people with cancer will receive both, one after the other, but they aren't the same thing.
Typical normal CT scan dose: 1-2 rem
Faulty CT scan overdose: 8-16 rem
1950s shoe-salesman's fluoroscope: 10 rem
Typical normal Therac-25 dose: 200 rem
Malfunctioning Therac-25 dose: 15-20,000 rem
Come on, seriously people. Yes, this is a mistake that needs to be fixed, but millions of kids in the '50s got their feet nuked with this much radiation and lived to become healthy normal adults with normal feet.
The Therac-25 cooked straight through people, leaving a hole of rotting meat behind. This is not even remotely in the same league.
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/Radiation.html
http://chestjournal.chestpubs.org/content/107/1/113.full.pdf
http://www.ccnr.org/fatal_dose.html
http://www.orau.org/ptp/collection/shoefittingfluor/shoe.htm
...But in that particular accident, the drunk is less likely to suffer severe or fatal injuries. The relaxant effect of alcohol makes their body more resilient to sudden shocks. Also, they're usually having a head-on collision, while they may be striking the other vehicle from the side; as head-on collisions are by far the most common, most of a car's safety features are geared toward mitigating them.
Don't you wish your girlfriend was a geek like me?
The person who reacts correctly to a slide is not doing so because he understands physics in general but because he has driving specific training. There's really no time to do math in that situation.
Woops, silly me, repeating what I learned in upper-division Transportation Engineering lecture from professors with decades of experience in the field of road design. Guess I should have checked Wikipedia first, because it never lies!
Got a cite for your critique?
It's true that the majority of people who die in alcohol-related crashes have a BAC of .08 or higher (67% according to this site). However, lower down, we see that 37% of single-car crashes involve a BAC of .08 or higher, which is higher than the 22% average rate. Since my point was about the comparative risks to the drunk driver and the sober driver in an accident, single-car crashes are irrelevant. That takes out 67% of the drunk driving crashes overall, and similarly lowers the fatality numbers considerably.
Don't you wish your girlfriend was a geek like me?