ENS 49537
ENS Event | |
|---|---|
08:00 Nov 8, 2013 | |
| Title | Agreement State Report - Y-90 Therashpere Dose Less than Prescribed |
| Event Description | The following report was received from the Washington Department of Health [WA DOH] via e-mail:
The licensee was performing an administration of Nordion TheraSpheres, a procedure performed without incident for over sixty administrations so far, when measurements indicated that an inordinate amount of the material remained in the waste/tubing. The licensee has confirmed the catheter used had an internal diameter [ID] of 0.68mm, which equals and exceeds the manufacturer's specifications of equal or greater than 0.5 mm ID. 1. On Friday, November 8, 2013 at approximately 1040 [PST], the RSO received notification of a possible medical event involving the administration of Y-90 microspheres (TheraSpheres). The Radiation Safety Specialist contacted WA DOH at approximately 1100 on Friday, November 8, 2013 to report a medical event in accordance with requirements in WAC 246-240-651. 2. The routine procedure for Y-90 microsphere administration requires the measurement of the materials used for the administration at a fixed geometry both before and after administration. The ratio of the exposure rate measured (minus background) indicates the percentage of the microspheres remaining in the tubing. This value subtracted from the originally prescribed activity determines the percentage of activity actually administered to the patient. The prescribed dose was 129 Gy to the left lobe, equivalent to an administered activity of 5.0 GBq. The measured activity (via Capintec CRC-15R) was 5.04 GBq which resulted in a pre-administration exposure rate of 5.3 mR/hr. Post-administration, the residual waste exposure rate measurement was 3.8 mR/hr (using the same geometry). The post-administration measurement was taken about 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after the pre-administration measurement. Based on the post administration measurement, it is estimated that at least 73% of the prescribed dose was still present in the waste materials implying that only 27% of the prescribed dose was administered or 1.36 Gbq which would result in a target dose of 35 Gy. 3. Investigation into the root cause indicated that the use of a Surefire Catheter may have been the underlying factor of this medical event. The interventional radiologist (RA) reported that this was the first time he had used the Surefire Catheter in conjunction with a TheraSphere case. This catheter was chosen due to medical need. The interventional radiologist wanted to minimize the amount of auxiliary embolization required for this case and this catheter satisfied that requirement. Prior to administration, contrast was administered to verify the integrity of the infusion system. No issues were noted during the contrast administration. During the administration of the microspheres, the interventional radiologist noted that the feel of the syringe was different from past administrations and that it was more difficult to push the plunger, however it did appear that the infusion was occurring. After completion of the infusion, the interventional radiologist noted that the syringe plunger pushed back. Final measurement of both the patient and the waste materials by medical physics and nuclear medicine indicated that the dose was not properly infused and consequently an underdose had occurred. 4. During the investigation it was noted that this case was the first time the Surefire Catheter was utilized. There were no other changes in the set up. The vendor representative mentioned that he had previously observed issues with the use of this catheter, however there are no documents or other notices issued with regards to catheter usage combinations. Review of the infusion materials did not reveal any physical issues with the setup, though based on the physician's report regarding the feel of the plunger during the infusion, it is possible that there was a kink or other similar issue in either the catheter or infusion system that resulted in incomplete administration of the TheraSphere dose. 5. The interventional radiologist communicated directly with the patient regarding this medical event. Both the interventional radiologist and the radiation oncologist (who is also the physician authorized user for this material) do not anticipate any additional medical issues that would be a result of this incomplete administration. This is based on the history of the patient who had previously received a TheraSphere administration to his right primary lobe vs. the current administration to the left secondary lobe. 6. In order to minimize the possibility of future medical events, the Surefire Catheter will not be used for future procedures. Since there have been no cases during our experience with this procedure prior to this event that have resulted in an underdosing due to equipment malfunction and since the only significant change in equipment set up was the use of the Surefire catheter, it is expected that a return to our previous catheter will insure that underdosing will not occur. 7. In accordance with WAC 246-240-651 a full report regarding this event has been transmitted to WA DOH. Washington Incident : WA-13-055 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 | |
|---|---|
| Swedish Hospital And Medical Center Seattle, Washington (NRC Region 4) | |
| License number: | WN-M008-1 |
| Organization: | Wa Division Of Radiation Protection |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+150.67 h6.278 days <br />0.897 weeks <br />0.206 months <br />) | |
| Opened: | Curt Demaris 14:40 Nov 14, 2013 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Nov 14, 2013 |
| 49537 - NRC Website | |
Swedish Hospital And Medical Center with Agreement State | |
WEEKMONTHYEARENS 495372013-11-08T08:00:0008 November 2013 08:00:00
[Table view]Agreement State Agreement State Report - Y-90 Therashpere Dose Less than Prescribed 2013-11-08T08:00:00 | |