ENS 43445
ENS Event | |
|---|---|
07:00 Jun 25, 2007 | |
| Title | |
| Event Description | On June 25, 2007, during a patient treatment, the computer operating the Varian VariSource High Dose Rate After loader reported an error 18, Wire drift detected. This indicated that the source wire positioning system was out-of-specification and the HDR was terminating treatment. Treatment was immediately discontinued and the patient removed from the room. The positioning QA was performed and the system found to be within typical operating limits. The treatment was resumed, but the same error recurred. Treatment was discontinued with only a partial treatment delivered. No errors in positioning or site occurred. The physician and patient were notified immediately after the treatment was terminated.
Varian Service was notified of the occurrence and a field engineer was dispatched to clean the system the following day. The source and dummy wire transport systems were cleaned and tested. The medical physicists performed several QA tests concerning positioning and source output, and certified the HDR After loader system as ready for patient treatment. Dosimetry reconstruction of the delivered dose indicates that 17.8% of the prescribed dose was delivered. Physician will reconstruct new treatment plan. Treatment Details: The patient was receiving HDR treatment #2 to a Miami vaginal cylinder with tandem. This apparatus is connected to the HDR After loader (with radioactive wire) with 7 separate connecting tubes, one for each treatment channel. During connection, bloody fluid was noted on one of the connectors, cleaned, and the tube connected. The treatment was initiated, but after that tube was treated, the device's computer indicated the wire positioning was not reproducible (error code 18 - Wire drift detected) and the treatment was paused. The QA positioning test was run and within acceptable limits. The treatment was continued, but the device again indicated positioning errors. The treatment was discontinued without being fully completed. Protective caps covering the tubes were removed in surgery instead of waiting until the patient arrived in the department, a typical procedure that had not caused an incident in the past. In the future, it is prudent to leave them connected until the patient is ready to be connected to the treatment device. Two lessons learned from this experience: For HDR cases using a tandem, the tandem channel should be treated first, since the prescribed dose is more influenced by tandem dose than by ovoids or vaginal cylinder. The protective caps on the applicator should be left on as long as possible to reduce or preclude any fluid in the closed system. Device: Varian VariSource High Dose Rate After loader, S/N#: 600379, SS&D #: CA-0661-D-103-S, Source: Alpha - Omega Model #: VS 2000, SS&D #: CA-1080-S-102-S, S/N #: 02-01-0588-001-041907-10089-97, Activity: 10.089 Ci on 4/19/07
This event (EN43443) has been reviewed and determined to be a reportable medical event. A "Medical Event" may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient. |
| Where | |
|---|---|
| Providence Medford Medical Center Medford, Oregon (NRC Region 4) | |
| License number: | ORE-91035 |
| Organization: | Or Dept Of Health Rad Protection |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+36.2 h1.508 days <br />0.215 weeks <br />0.0496 months <br />) | |
| Opened: | Kevin Siebert 19:12 Jun 26, 2007 |
| NRC Officer: | Jeff Rotton |
| Last Updated: | Jun 26, 2007 |
| 43445 - NRC Website | |
Providence Medford Medical Center with Agreement State | |
WEEKMONTHYEARENS 434452007-06-25T07:00:00025 June 2007 07:00:00
[Table view]Agreement State Oregon Agreement State Report - Underdose Due to Equipment Malfunction 2007-06-25T07:00:00 | |