POTENTIAL OVEREXPOSURE OF RADIOGRAPHER
The following was received from the Mississippi Division of Radiological Health via phone:
A radiographer was exposed to a 100 Curie Ir-192 source for 8 minutes while changing film during a radiography shot. The radiographer was not wearing dosimetry and did not have a hand held radiation meter. While changing film, the radiographer realized the source had not been retracted and left the area. This was not an equipment malfunction, and the source was retracted when it was realized that the radiographer had been exposed. The radiographer reported the event to the Mistras Radiation Safety Officer (RSO). Estimated dose is 20 Rem to the hands and 19.6 to 19.7 Rem whole body. The radiographer was sent to a local hospital for bloodwork.
* * * UPDATE FROM ROBERT SIMS TO HOWIE CROUCH VIA EMAIL AT 1706 EST ON 11/8/19 * * *
"[A state of Mississippi Health Physicist investigator] interviewed the RSO on 11/7/2019 and investigated the incident. After reviewing and questioning the incident details, [the investigator] found the following evidence that may determine this may not have been an overexposure. The assistant radiographer retracted the source, but did not perform the bump test to fully retract the source into the locked position. This caused the assistant radiographer to believe the source was still in the collimator. When returning to change the film, he saw the red button on the camera instead of green which would indicate the source was in the locked position. The assistant was not using dosimetry, rate alarm or survey instrumentation. He appears to have panicked, came down the ladder, and couldn't get the crank to move in. The lead radiographer then grabbed the crank and cranked out and back in immediately to fully retract the source into the camera. [The investigator] reviewed compliant leak tests of camera and wipes along with maintenance and service reports before and after the incident and the RSO could not replicate any problems that would prevent them from retracting the source. There was no malfunction with the camera or the cranks. It appears that the source was in the end of the camera but not in the fully shielded position, which could allow some radiation out of the tube that the source enters. However, we do not know how much because the assistant was not wearing any dosimetry. The other assistant's dosimetry only picked up 1 milliRem of dose but he was approximately 25 ft. away with steel shielding from the tank they were working on in between him and the source. [The investigator is] waiting on the emergency reading of the doses recorded on the OSL badges used by the crew and follow up doctor's visit. [The investigator] interviewed [the assistant radiographer on] 11/8/2019 at 1549 CST. [The assistant radiographer] reports that he had more blood drawn today and will provide results next week. He said he feels great and has had no sickness such as nausea, pain or redness and swelling in the hands. Will update again next week after receiving lab results." |