At this point, most people in the device industry are aware of the recent rash of excess radiation delivered to patients. The problem, in various forms, was reported in California, Alabama, Illinois, and so on. The New York Times is taking yet another look at the problem through the eyes of a woman who went in for stereotactic radiosurgery (SRS), which is used to treat brain and spinal cord tumors and other anomalies. Unfortunately, a linear accelerator allowed radiation to seep outside of the targeted area of the brain. The woman ended up in almost comatose in a nursing home and unable to speak, eat, or walk.

So who is held accountable in radiation overdose situations like this? Were the operators at fault, or was the design faulty? In this case, the linear accelerators were redesigned by the manufacturer, Varian Medical Systems, to be able to perform SRS. Apparently, problems arose as the devices became more versatile and complex. The electronic components within the machine were not communicating with each other. The NYT says that devices from Varian and its frequent partner Brainlab have been involved in numerous reports of errors and overdoses over the past five years. Varian declined to be interviewed but expressed "deep concern" over the aforementioned tragedy and said that “our products include many built-in safety features, and we work continually to make them even safer.”

The writer posits that this situation is indicative of problems in the regulation of medical radiation. For example, linear accelerators don't use radioactive material to generate radiation, so they are regulated by FDA. And the retrofitted linear accelerators were approved with minimal review because they were seen as an extension of existing technology. A competitor product such as the Gamma Knife is overseen by the Nuclear Regulatory Commission because it uses a radioactive isotope.

(Also, check out the accompanying interactive graphic that shows how linear accelerators work and what can go wrong.)

Most people who undergo SRS or similarly innovative procedures come out of it just fine. But when problems like this arise, it simply underscores the need for prudent choices in design. —Lawrence Lloyd