The following information was provided by the licensee via email:
At about 1000 EDT on 4/19/23 the licensee was performing an HDR treatment on a patient's cervix using a Nucletron B.V 136149A02 model Flexitron HDR remote after loader containing a 12 Ci Ir-192 source. The applicator has three sections: right and left partial rings on either side of the cervical os, and a tandem inserted into the cervix. The intended dose was 500 centi-Gray (cGy) to points called Right A and Left A, 2 cm up and 2 cm out from the cervical os.
Computed clinical dose to the patient was 156 cGy to the A points which is 31 percent of what was prescribed. The total dose for the four treatments is 1,656 cGy which is 83 percent of prescribed.
The HDR unit functioned properly in treating the first section, the right ring. It then treated the left ring properly, but at the end of treatment it gave an error message, and the radiation monitors in the room and above the door indicated that the source did not return to the safe position. As a result, the treatment was shutdown, and emergency procedures instituted. The tandem was not treated.
After several unsuccessful attempts to bring the source to the safe position, the applicator was removed from the patient, the patient was removed from the room, and the room was closed and sealed.
Preliminary dose estimates received by personnel are as follows:
Authorized User - 10,000 mrem
Medical Physicist - 10,000 mrem
Nurse Anesthetist - 700 mrem
Radiation Technician - 4,000 mrem
Radiation Technician - 700 mrem
Badge dosimetry was collected and sent for processing to confirm actual doses received.
Staff were successful in returning source to a safe condition, and a manufacturer representative will be conducting an inspection of the device before further use.
No adverse effects anticipated to the patient from this event, and the shortfall in dose will be made up at a future date.
- * * UPDATE ON 04/21/23 AT 0930 EDT FROM KELLY STONEBERG TO KERBY SCALES * * *
The following update is a summary of information received from the licensee via email:
Initial dose estimates for the individuals who were present in the room while the HDR source was outside the HDR unit due to malfunction of the unit were conservatively estimated to be greater than the 5 rem reportable limit. The dosimeters were immediately sent out for processing after the event and the actual readings were below the reportable limit. The individual's readings were as follows:
Radiation Technician 1 - 87 mrem
Radiation Technician 2 - 2 mrem
AMP - 47 mrem
Notified R1DO (Arner), NMSS (Rivera-Capella) and NMSS Events Notification via email.
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.