A member of the Angers University Hospital nuclear medicine department personnel suffers overexposure of the hands
On 31st January 2019, the Angers University Hospital informed ASN (the French nuclear safety authority) of a significant radiation protection event in which a member of personnel exceeded the regulatory annual limit for exposure to the hands, which is set at 500 millisieverts. The person concerned by this event works in the hospital's nuclear medicine department.
Nuclear medicine is an imaging techniquethat uses radionuclides for diagnostic or therapeutic purposes. Specialised personnel are responsible for the preparation, quality control, dispensing and traceability of the radiopharmaceutical products used. These operations can therefore expose the personnel to ionising radiation.
Due to the late forwarding of the staff dosimeters worn in November 2018 to the laboratory responsible for reading them, the event was not discovered until January 2019 when the dosimetric monitoring results were received. The results revealed that a member of staff had received an equivalent dose to the hands of 723 mSv during the month of November 2018.
Given that the annual exposure limit for the extremities has been exceeded, ASN rates this event level 2 on the INES scale (international scale of nuclear and radiological events, graded from 0 to 7 in increasing order of severity).
The nuclear medicine department conducted investigations to determine the cause of exceedance of the exposure limit, without success.
ASN carried out an inspection on 1st February 2019 which also failed to determine the exact circumstances of the overexposure. It did however highlight malfunctions in the management and analysis of the dosimetric devices and identified areas for improvement in the performance of the checks for non-contamination after handling radiopharmaceuticals, and in the recording of these checks.
The follow-up letter to this inspection can be consulted on the ASN website (link below).
The overexposed person will not handle radionuclides for a period of twelve months.
ASN firmly underlines the obligation for all workers who are exposed to ionising radiation to wear all their dosimeters, particularly in situations of potentially heterogeneous exposure of the hands, in order to detect any abnormal exposure as early as possible.