The State provided the following information via email:
ODH Bureau of Radiation Protection received a phone call from Varian Medical Systems at approximately 3:15 PM EDT regarding a situation which had occurred at a customer's location (St. Elizabeth Hospital in Youngstown, Ohio). The incident occurred at approximately 2:15 PM EDT. A Varian technician was performing maintenance on a Gamma Med Model 12i HDR unit, with the source extended into a shielded safe. During the maintenance action the technician disconnected a nylon tube that was part of the source wire travel path. This action caused the retract mechanism in the unit to energize, retracting the source wire from the safe, exposing approximately 8 inches of the source wire and the source end. The source is approximately 9.5 Curies of Iridium-192.
Varian personnel believe that the disconnection of the nylon tube reduced the tension on the source wire, causing the park switch to no longer sense the presence of the wire, and energizing the retraction mechanism, which then pulled the source from the safe. The technician realized that something was not right when he heard the drive mechanism energize, and exited the treatment room immediately. Varian estimates the exposure to the technician as approximately 15 mrem, based on the activity of the source and time required to exit the room. The technician was not wearing his dosimetry at the time the incident occurred.
Varian is sending an additional engineer to the customer location to assist with source recovery, with an estimated arrival time between 7:00 PM and 8:00 PM EDT. Varian has set-up a mock scenario at their office with the same model unit in the same configuration as what is present at the customer site. They have performed run throughs of source recovery, and have determined that the most effective method of retrieval will be to grasp the source wire with 18" forceps and then guide the source wire back into the shielded safe. They expect the evolution to take 5 - 8 seconds with an estimated whole body exposure of 25 mrem or less.
Ohio report # 2007-046