ENS 40797
ENS Event | |
|---|---|
18:25 Jun 8, 2004 | |
| Title | Medical Event at the William Beaumont Hospital in Royal Oak, Mi |
| Event Description | On Tuesday, June 8, 2004 at 2:25 p.m., a patient was scheduled for an I-131 thyroid uptake with an oral dose between 5 and 20 microcurie. Instead, the patient was administered 915 microcurie (34 MBq), which resulted in an absorbed dose of 2675 rad to the thyroid (assuming a 55% radioactive iodine uptake) and 81 rad effective dose equivalent.
Each Month the Radiopharmacy prepares an oral solution of sodium iodide I-131 for uptake doses which are pipetted into individual patient dose vials. The sodium iodide I-131 uptake solution for June contained 12 microcurie per milliliter (ml) in a total volume of 300 ml. The Radiopharmacy technologist prepared the uptake dose by pipetting one ml of solution into the patient vial, which, should have yielded a dose of approximately 12 microcurie. The pipette that the Radiopharmacy technologist used to prepare this dose had been used earlier in the day to prepare therapeutic doses of I-131, and was labeled as the therapy pipette. The Radiopharmacy technologist did not realize that she had picked up the pipette labeled for therapy and assumed it was the pipette used for preparing the uptake doses. Usually the uptake pipette is stored in a shielded vial in the far right corner of the fume hood, but in this case, the therapy pipette was located in the far right corner. The Radiopharmacy technologist assayed the dose in the dose calibrator and noted that the reading was too high for an uptake dose. This caused the staff to question which pipette was used, and they confirmed that the therapy pipette was used. The Radiopharmacy staff discarded the dose in accordance with radioactive waste procedures, and proceeded to draw another uptake dose with the pipette labeled for uptakes. One milliliter was drawn and assayed in the dose calibrator and read 0.915 mCi/ml. The Radiopharmacy technologist accepted the dose thinking that it was really 9.15 microcurie instead of 0.915 millicurie. The computer program is set up to accept I-131 uptake doses on the basis of correct volume and since the volume was within the acceptable range of 1 ml, the computer printed a label for the dose and it was dispensed. The nuclear medicine technologist followed the procedure for confirming the dose prior to administration by checking the patient name, ID number, the I-131 uptake procedure and circling the dose. She looked at the dose printed on the label and thought that the dose was 9.15 uCi instead of the what was printed on the label (0.915 mCi), and administered the dose to the patient. The Radiopharmacy technologist became concerned about using the wrong pipette and contacted the Radiopharmacist, who then discovered the error. The therapy pipette contained residual millicurie amounts of therapeutic I-131 solution which contaminated the I-131 uptake dose. B. Why the Event Occurred The root cause was determined to be the lack of an adequate double check of the I-131 uptake dose prior to administration. A pipette contaminated with 2 millicurie I-131 was inadvertently used to prepare the uptake dose. The Radiopharmacy computer was programmed to detect volume errors, but not activity errors, so it accepted the dose and printed the label. The Radiopharmacy technologist did not detect the error when she assayed the dose for this second redraw, because she assumed that the activity displayed 9.15 uCi, rather than the actual activity displayed, which was 0.915 mCi. The nuclear medicine technologist who double checked the dose mistook the 0.9 mCi for 9 uCi on the dose label and administered the dose. She had been working in an imaging room, but was needed to cover the thyroid uptake room near the end of the work shift. This may have contributed to the error made when confirming the dose. C. The Effect on the Patient The absorbed dose to the thyroid was 2675 rad (assuming a 55% radioactive iodine uptake) and the effective dose equivalent was 81 rad. The patient is expected to return to William Beaumont Hospital tomorrow (6/9/04) for treatment with I-131 for hyperthyroidism. The additional dose given for the uptake is a fraction of the dose that will be administered for therapy. The patient is not expected to have any adverse effects. D. What improvements are Needed to Prevent Recurrence A complete investigation was conducted to determine the root cause of the medical event. A new pipette will be used for each I-131 uptake patient dose, which will prevent the cross contamination. The computer will be re-programmed to accept uptake dose activity (ie., 5 - 20 microcurie) rather than volume. The computer will not print a label for the uptake dose unless the activity is within the predefined range. The radiopharmacy staff have been trained not to over-ride the failsafe mechanisms of the computer. The nuclear medicine technologist will be retrained in the dose verification process prior to a dose administration. Both the Radiopharmacy technologist and the nuclear medicine technologist will review the dose units (i.e., microcurie, millicurie, MBq) and pass a test. E. Actions Taken to Prevent Recurrence 1. A new pipette will be used for each I-131 uptake patient dose, which will prevent the cross contamination. 2. The computer will be re-programmed to accept uptake dose activity (i.e., 5 - 20 microcurie) rather than volume. The computer will not print a label for the uptake dose unless the activity is within the predefined range. 3. The nuclear medicine technologist will be retrained in the dose verification process prior to a dose administration. 4. Both the Radiopharmacy technologist and the nuclear medicine technologist will review the dose units (i.e., microcurie, millicurie, MBq) and pass a test. |
| Where | |
|---|---|
| William Beaumont Hospital Royal Oak, Michigan (NRC Region 3) | |
| License number: | 21-01333-01 |
| Organization: | William Beaumont Hospital |
| Reporting | |
| 10 CFR 35.3045(a)(1) | |
| Time - Person (Reporting Time:+-1.37 h-0.0571 days <br />-0.00815 weeks <br />-0.00188 months <br />) | |
| Opened: | Cheryl Schultz 17:03 Jun 8, 2004 |
| NRC Officer: | Chauncey Gould |
| Last Updated: | Jun 8, 2004 |
| 40797 - NRC Website | |
William Beaumont Hospital with 10 CFR 35.3045(a)(1) | |
WEEKMONTHYEARENS 429752006-11-07T18:45:0007 November 2006 18:45:00
[Table view]10 CFR 35.3045(a)(1) Medical Event - Less than Prescribed Dose of Yttrium - 90 ENS 407972004-06-08T18:25:0008 June 2004 18:25:00 10 CFR 35.3045(a)(1) Medical Event at the William Beaumont Hospital in Royal Oak, Mi 2006-11-07T18:45:00 | |