A permanent prostate seed implant was performed on 12/21/07. Following this case there were 18 unused seeds remaining. Unused seeds are kept in the original shielded container provided by the vendor and stored in the nuclear medicine hot lab until returned by the Radiation Safety Officer (
RSO) to the vendor for ultimate storage and disposal. Unused seeds are normally returned once each quarter by the
RSO.
In this case, however, the nuclear medicine technologist transferred the 18 seeds from the shielded container to a lead-lined radioactive waster bin for the storage of dry-solid active waste such as gloves, absorbent pads, etc. potentially contaminated with Tc-99m. This waste bin is not used for medical waste such as syringes, sharps, etc.
The dry-solid radioactive waste bins are held for decay-in-storage. Based on the preliminary information and a review of the radioactive waste disposal log, this particular bag was surveyed and disposed of on either 1/10/08 or 2/6/08. Since they use two bins and hold for radioactive decay until the other is full, it is not clear at this time as to which bag was disposed in the regular trash. Discovery of the lost material was through inquiries by the RSO concerning how many unused seeds were available this quarter for return. If the seeds were disposed of in the regular trash on 1/10/08, the activity lost would be 5.03 milliCuries; if disposed of in the regular trash on 2/6/08, the activity lost would be 3.68 milliCuries.
The possible disposition of the licensed radioactive material at this time is the landfill. A detailed written description of the incident will be submitted within 30 days.
The State of Wisconsin plans to investigate this incident on an upcoming inspection.
Wisconsin Event Report ID: WI080004
THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL
Sources that are "Less than
IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as
moisture density gauges or thickness
gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks.