Beginning on March 14, 2005, Scott Jerome-Parks received intensity modulated radiation therapy (IMRT) as a treatment for his tongue cancer. (As Jerome-Parks did not fit the typical profile of a tongue cancer sufferer, it is thought that perhaps exposure to the dust from the World Trade Center collapse on 9/11 may have contributed to the disease.) He had received these treatments before, but this time something was different. The therapist had reprogrammed the machine at the request of Jerome-Parks’ doctor to minimize damage to his teeth (an unfortunate side effect of radiation therapy near the mouth). During the reprogramming, the computer had crashed and although the therapist was asked if she would like her changes saved, some of the programming was lost – specifically, the collimator settings.
In IMRT, the radiation beam comes down through a collimator, which has programmable leaves (that look like metal teeth) that open and close to direct and modulate the beam. If the collimator leaves are completely closed, no radiation gets through. If the collimator leaves are completely open, the dose of radiation will be too high, and the beam will not be properly directed to the desired radiation site (here, Jerome-Parks’ tongue) but will rather hit a larger part of the body.
In this case, the collimator settings were lost, which resulted in the collimator being wide open, delivering seven times the desired dose to Jerome-Parks. The error was not noticed until 3 days – and 3 treatments – later, when the physicist performed a test to verify the programming and discovered the overdose. It was apparently customary, though not required, that the therapist verified the settings after reprogramming. On this day, the hospital was apparently short-staffed due to therapist training, so the verification test was delayed.
Jerome-Parks eventually died of his injuries. He hoped that his death would lead to fewer radiation errors like the one that killed him. Some progress is being made, but there’s still a way to go.
The company who manufactured the IMRT equipment released a new version of the software which contains a fail-safe to reduce the risk of the modulator being left wide open. Although the details aren’t clear, it appears that the default setting for the equipment was to have the collimator wide-open, resulting in an overdose, rather than closed, which would result in no radiation at all. It also was difficult for the therapists to determine which of their changes had been saved when the computer crashed, which apparently happened frequently.
It’s unclear what changes the hospital involved is making to its procedures to reduce the risk of this type of error. However, there were several opportunities for the error to be caught, so there are some effective changes that could be made. The State of NY, concerned with the number of radiation errors, especially high-profile ones like that of Jerome-Parks, has released several alerts to draw attention towards the problem of radiation errors. It’s also attempting to increase reporting requirements (now practically non-existent) for these types of errors to increase accountability. Let’s hope that it works and nobody has to suffer like Jerome Parks again.
If you’d like to learn more about Jerome-Parks and radiation errors, check out the article by the New York Times. For more on radiation errors, check back at our blog next week!