A complaint was recently received for a problem involving a flex pivot joint failure.The primary collimation system is comprised of two jaws that control the width (thickness) of the radiation beam.The two halves of the jaw are opened and closed with electric actuators.These actuators are held on mounting brackets by flex pivots which allow rotation while providing a tight fit.In this case, the flex pivot joints cracked (likely due to a torque issue), and the width of the radiation beam was not appropriately collimated resulting in under-dose by 2-11%.Subsequent compensating fractions were delivered according to a physician approved treatment plan.We were informed that the customer/user submitted a medwatch report.
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