ENS 48058
ENS Event | |
|---|---|
07:00 May 2, 2012 | |
| Title | Agreement State Report - Potential Medical Event Due to Leaking I-125 Seeds |
| Event Description | The following was received via e-mail:
On 6/28/12 Saint Joseph Hospital personnel were surveying a packing materials used to ship I-125 seeds, for a procedure conducted earlier that day, when they noted elevated readings. Further surveys revealed that the elevated readings were not coming from the packing material associated with the 6/28/12 procedure but from packing material that was used to ship I-125 seeds for a previous procedure, which was in the area of the survey. Surveys of the packing material revealed no loose contamination on the exterior or interior of the box but elevated readings of 2500-350000 cpm and .2 mrem/hr. Receipt and post procedure surveys of the procedure associated with contaminated box did not reveal any abnormal readings. The Saint Joseph RSO assumes the material is I-125 but they do not have the capability to verify this. No loose seeds were found in any of the packing material. The I-125 seeds were accompanied by the manufacturers leak test report which indicated no contamination. The patient, whose procedure was associated with the contaminated packing material, will be evaluated on Monday 7/2/12 to determine if there was any uptake in his urine or thyroid of I-125 as a result of leaking seeds. CA Report Number: 062912 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.
This is a follow up of an incident, as information only, on Friday, June 29, 2012. Radiologic Health Branch reference would be 5010 #062912. The notification was about contaminated packaging that had contained Best Medical I-125 seeds. A thyroid count was performed on the patient who had the seeds implanted in May. The thyroid count verified that there had been an uptake of iodine by the thyroid. Below is the write up and preliminary dose estimate from the licensee regarding. Based upon this morning's patient measurements, instrument-manufacturer supplied efficiency data, and reference data for dose conversion, we estimate the patient involved received a thyroid uptake of 0.1 mCi of I-125 and a dose to the thyroid of 300 cGy. 1) Conversion of counts per minute (cpm) to activity Two[Pi] counting efficiency for I-125 (per manufacturer) is 133.5% fraction of 2[Pi] solid angle subtended by a 2 inch diameter detector at a distance of 30 cm from the thyroid is 10.13 squared cm / 5654.9 squared cm = 0.00179 overall efficiency = 1.335 x 0.00179 = 0.00239 (190493 - 30) net cpm / 0.00239 x 4.505x10-10 mCi/dpm = 0.0359 mCi present thyroid burden. Back-correcting 60 days to time of implantation (conservatively assuming that all uptake occurred at that time) with 42-day effective half-life, initial uptake given by 0.0359 / 0.3715 = 0.0967 approximately 0.1 mCi 2) Taking the value quoted by Chen et.al. (attached) from NUREG/CR-6345, we assume the dose to thyroid is 780 cGy per mCi of I-125 administered, and this value assumes 25% uptake into the thyroid. Our calculated estimated thyroid burden of 0.1 mCi then gives an estimated absorbed dose of 0.0967 mCi x 780 cGy/mCi / 0.25 (since we measured actual thyroid burden v. amount administered) = 302 cGy approximately 300 cGy (rad) to thyroid. 3) Whole body committed effective dose equivalent (CEDE) from a 300 rad dose to the thyroid (using a thyroid weighting factor of 0.04) would be 12 rem. Notified R4DO (Allen) and FSME (Einberg).
EVENT SUMMARY: While surveying an empty brachytherapy seeds package for return to Best Medical hospital personnel discovered contamination on the interior of the package. Follow up thyroid scans of the patient who was implanted with the seeds associated with the package verified an uptake of I-125 by the patient's thyroid. The initial report to RHB was intended, by the licensee, to be a notification of a Medical Event. REPORTING: This event was reported to the NRC, by phone, on 4/13/12, at 8:50 am via email. HEALTH AND SAFETY: Based on surveys of the packing material all contamination was contained within the package and did not pose a threat to hospital personnel. The estimated dose to the patient's thyroid was calculated to be approximately 330 rad with a CEDE of 12 rem. ADDITIONAL DETAILS: The RSO conducted an investigation of the incident and could not find any indication that there were any irregularities with the implantation procedures. Hospital personnel associated with the procedure indicated to the RHB inspector that there were no irregularities with the procedure. In addition receipt surveys of the package did not reveal any contamination of any of the packaging material. The RSO concluded that the cause of the contamination was due to a manufacturing error. The RSO of Best Medical conducted an investigation of the production of the seeds implanted in the patient. All records at Best Medical indicate that all QC tests of the seeds were done satisfactorily. The RSO concluded that the seeds had been damaged in transit or that Saint Joseph personnel must have damaged the seeds either during the initial surveys or during the implantation. The Best Medical RSO was unable to explain how the seeds could have been damaged and still be implantable. The Virginia Department of Health inspected the Best Medical facility and concluded that all QC testing on the seeds had been completed satisfactorily with no abnormalities noted. After interviewing Saint Joseph and Best Medical personnel RHB personnel concluded that the most logical explanation for the leaking seeds was a manufacturing error, however, without samples from the same lot of seeds implanted available for analysis this can not be proven conclusively. The hospital has changed suppliers for the brachytherapy seeds. In addition they have initiated a procedure where the needles containing the seeds are wiped after they have been removed from the shipping container. ENFORCEMENT ACTIONS: The hospital was not cited for this incident. INVESTIGATION STATUS: This investigation is closed. Notified R4DO (Spitzberg) and FSME Event Resource via email. |
| Where | |
|---|---|
| Saint Joseph Hospital Eureka, California (NRC Region 4) | |
| Organization: | California Radiation Control Prgm |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+1400.98 h58.374 days <br />8.339 weeks <br />1.919 months <br />) | |
| Opened: | Kent Prendergast 15:59 Jun 29, 2012 |
| NRC Officer: | Joe O'Hara |
| Last Updated: | Dec 20, 2012 |
| 48058 - NRC Website | |
Saint Joseph Hospital with Agreement State | |
WEEKMONTHYEARENS 516702015-11-09T07:00:0009 November 2015 07:00:00
[Table view]Agreement State Agreement State Report - Medical Event Involving High Dose Rate Therapy ENS 484652012-10-17T22:37:00017 October 2012 22:37:00 Agreement State Agreement State Report - Possible Medical Event Involving Misadministration ENS 480582012-05-02T07:00:0002 May 2012 07:00:00 Agreement State Agreement State Report - Potential Medical Event Due to Leaking I-125 Seeds ENS 478312012-04-04T07:00:0004 April 2012 07:00:00 Agreement State Agreement State Report - Tc-99M Generator Inadvertantly Sent to Non-Licensed Recipient ENS 474842011-11-25T08:00:00025 November 2011 08:00:00 Agreement State Agreement State Report - Package Containing Radioactive Material Left Unattended 2015-11-09T07:00:00 | |