THERAC-25
Do you remember those horrible accidents in '86 and '87?
Do you remember one patient's description "something had hit him on the side of the face, he saw a flash of light, and he heard a sizzling sound reminiscent of frying eggs". He was very agitated and asked, "What happened to me, what happened to me?"
Does MALFUNCTION 54 sound familiar?
We came to the rescue of AECL Medical by performing extensive analysis of the software for this linear particle accelerator-based cancer therapy machine.
One writer wrote "A close inspection of the code was also conducted during this safety analysis to obtain more information on which to base decisions. An outside consultant performed the inspection... No information is provided in the final safety report about whether any particular methodology or tools were used in the software inspection or whether someone just read the code looking for errors."
The "outside consultant" and "someone" was us and our in-depth analysis encompassed much more than reading the code looking for errors. But, of course, the details of exactly what we performed is protected by a confidentiality and non-disclosure agreement.
Despite all of the articles that have been written, aside from the manufacturer, we know more about the safety of this device than anyone.
By the way, take a look at our expertise in post-accident safety analysis.
More recently (October 8, 2009), the following post appeared on the FDA web site.
FDA has become aware of radiation overexposures during perfusion CT imaging to aid in the diagnosis and treatment of stroke.
Over an 18-month period, 206 patients at a particular facility received radiation doses that were approximately eight times the expected level. Instead of receiving the expected dose of 0.5 Gy (maximum) to the head, these patients received 3-4 Gy. In some cases, this excessive dose resulted in hair loss and erythema. The facility has notified all patients who received the overexposure and provided resources for additional information.
While this event involved a single kind of diagnostic test at one facility, the magnitude of these overdoses and their impact on the affected patients were significant. This situation may reflect more widespread problems with CT quality assurance programs and may not be isolated to this particular facility or this imaging procedure (CT brain perfusion). If patient doses are higher than the expected level, but not high enough to produce obvious signs of radiation injury, the problem may go undetected and unreported, putting patients at increased risk for long-term radiation effects.