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Radiation oncologists use more than a dozen quality assurance (QA) checks to prevent radiotherapy errors, but until now no one has systematically evaluated their effectiveness. Hopkins team gathered data on about 4,000 "near miss" events that occurred during 2008-2010 at the two institutions.
The group's key finding was that a combination of approximately six common QA measures would have prevented more than 90 percent of the potential incidents. "While clinicians in this field may be familiar with these quality assurance procedures, they may not have appreciated how effective they are in combination," says Eric Ford, professor at Johns Hopkins.
Ionizing radiation such as gamma radiation or proton beam radiation has long been a staple in cancer treatment, because it can efficiently create cell-killing DNA breaks within tumors. The goal is to use it in ways that maximize the dose delivered to a tumor, while keeping healthy tissue around the tumor as protected as possible by sharply focusing the radiation treatment area.
Unfortunately, the multistep complexity of radiation therapy, and the numerous precision measurements its use entails, can sometimes lead to mistakes, with patients getting too little radiation where it's needed, or too much where it isn't.
One QA check, a piece of hardware called an Electronic Portal Imaging Device (EPID), is built in to many radiotherapy-delivery machines, and can provide a real-time X-raylike image of the radiation coming through a patient. But Ford says less than one percent of radiotherapy clinics use EPID because the software and training needed to operate are mostly absent.
The checklist includes reviews of patient charts before treatment by both physicians and radiation-physicists, who calculate the right dose of radiation.
A common QA measure known as pretreatment IMRT (intensity modulated radiation therapy), in which clinical staff do a "test run" of the radiotherapy device at its programmed strength with no patient present, ranked very low on the list – because it would have prevented almost none of the potential incidents studied. "This is important to know, because pre-treatment IMRT often consumes a lot of staff time," says Ford.
MEDICA.de; Source: Johns Hopkins Medicine