|AGREEMENT STATE REPORT - IODINE-125 PROSTATE IMPLANT SEED
The following is a synopsis of a report from the Vermont (VT) Department of Health (the Department):
On November 27, 2019, a prostate seed implant (PSI) procedure using Iodine-125 (I-125) seeds was performed. During the latter part of the procedure, while loading one last, extra needle for the radiation oncologist (the Authorized User), the authorized medical physicist (AMP) lost control of one I-125 seed.
A number of surveys were conducted immediately following the loss of the seed, producing only background readings.
On December 4, 2019, a Department Senior Radiological Health Specialist conducted a follow-up survey in the PSI procedure room and waste storage areas. The lost seed was not located.
As a corrective action, the licensee may consider ordering additional seeds in the form of preloaded needles to avoid handling individual prostate seeds.
The lost prostate seed is believed to have fallen into the bore of the implanting needle and was subsequently implanted into the prostate. This is not believed to have any clinical significance on the resulting absorbed dose to the prostate, urethra, or rectum. The patient had 76 prostate seeds planned to be implanted and a single extra seed would result in approximately 1 percent additional absorbed dose to the treatment volume.
As verification, a post-implant treatment plan was calculated with an extra prostate seed placed near the location of the last needle within the treatment volume. The resulting dose metrics confirmed that absorbed doses increased by about 1 percent.
The potential radiation exposure to an individual that is continuously present near the lost seed was evaluated and determined to be less than the 0.1 rem annual public exposure limit.
No personnel contamination occurred as a result of this event.
VT Incident Number: VT19-002
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 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