The investigation was completed by conducting a thorough evaluation of the product and the reported information.The customer reported a discrepancy between the treatment fields' parameters in mosaiq and the imported plans.Elekta used the same plan in-house provided by the customer to evaluate import processing and found that plan promotion works as expected.The parameter values (e.G., gantry, collimator, field size, etc.) in mosaiq matched those of the plan.Once promoted, the plan is in a pending state and values can be changed without version roll until the plan has been approved or treated.From the logs it was determined that changes by the user from the original plan occurred after the initial plan was imported and were accepted by the user.Based upon information available elekta physics have assessed the severity of mistreatment as serious.One field was treated with an incorrect geometry which means that radiation was delivered to an area that was intended to receive little or no radiation.The dose to that area is estimated to be an overdose of 560cgy or ~19% of the intended dose.This represents a serious mistreatment from the perspective of dosimetric error.Additionally, on two other days fields were delivered twice instead of an intended once.However the total number of delivered fields over the course of treatment appears to be as intended.There is an expected radiobiological impact associated with delivering the incorrect daily dose while maintaining the overall intended total dose, however the impact of this is smaller than the impact associated with the exposure of radiation dose to an unintended area mosaiq did not have any malfunction and worked as designed and intended.The issue was due to use error.
|