The following report was obtained from the State of
Maryland via e-mail:
As follow-up to a telephone discussion [on the] afternoon of Sept. 14, 2010 at 1445, [the RSO sent the State of Maryland] this email as a written notification of a presumed lost sealed source containing radioactive material. The telephone notification and this email serve [as] compliance with Section D.1201a, which requires an immediate report of a theft or loss of a source of radiation.
The sealed source in question contains Germanium-68, a nuclide of half-life 271 days. This nuclide decays to Gallium-68, which itself then decays (with positron emission) with a half-life of 68 minutes to stable Zinc-68. The annihilation radiation from the positron emission is used for PET scanner quality assurance, as in the case of this source.
This sealed source originally contained 500 microCi of Ge-68 on March 1, 2000. The contained activity of the lost source has been computed to be 0.03 microCi (59000 dpm) as of the date of this notice. The exposure rate of a 1 microCi point (unsealed) source is 5.4 mR/hr at 1 cm; therefore, the exposure rate estimated for this sealed line source at 0.03 microCi is about 0.1 to 0.2 mR/hr at 1 cm. A description of the physical source is [as follows]. The source was manufactured by IPL (product code HEGL-0109) and is 6 inches in length and 1/8 inches in diameter with steel encapsulation.
The source had been stored and not used (due to low activity), and was last inventoried (and leak-tested) on July 22, 2010. An investigation is currently underway to determine the disposition of this source, and will be submitted to the MDE RHP [Maryland Department of the Environment, Radiological Health Program] per D.1201b within thirty days of this notice.
The State of Maryland will be conducting a follow-up investigation.
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. For additional information go to
http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf