NRC Information Notice 2009-15: Varian Medical Systems Varisource High Dose-Rate Remote Afterloader Events: Source Retraction Problems

Dear Medical Use Licensee:

The NRC issued the attached Information Notice 2009-15 to licensees regarding recently reported events at three different locations where service engineers experienced problems with the VariSource HDR during source retractions. During all of the incidents, the source wire became stuck outside of the afterloader and required the Varian personnel to use the manual-retract handle to return the source to a safe-shielded position. All of the incidents occurred because of an accumulation of dust buildup in the source wire path. Analysis of the dust particles has shown that the dust is composed of the same material as the nickel titanium source wire. Varian implemented special maintenance procedures, including the routine cleaning of any components exhibiting dust buildup on a regular basis. Varian has released information regarding these events to its customers in Customer Technical Bulletin CTB-VS-640A.