- Details
- Parent Category: Reports - Medical and Veterinary
- Category: Brachytherapy
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- France
pdf Brachytherapy – Loss of an iridium wire (Report No. 2) (70 kB)
Description of the incident
Iridium-192 wires were used for the treatment of genital cancer by endocavitary brachytherapy using a vaginal mould. At the end of the treatment, the doctor first withdrew the Ir-192 wires (whose number had not been specified) without counting them and then removed the vaginal mould.
During this procedure, one of the wires was left in the mould. During the subsequent cleaning of the mould, the wire slipped and became lodged into a groove in the washing mat. However, this was not noticed at the time.
The next day, after checking the container where wires are stored, the radio-physicist noted the absence of a wire. A search with a radiation meter revealed the location of the missing wire.
Radiological consequences
No estimates of the doses potentially received by persons were reported; and the linear activity or the length of the wire were not specified either. However, assuming typical dose rates for this type of source (3 mSv/h on contact and 20 µSv/hr. at 1 m), the doses received from this specific incident are thought to have been low (probably only a few µSv).
Lessons to be learned from the incident
During the placement of iridium-192 wires, it is imperative the number of wires used is known and recorded, and that they are counted when removed.
A simple radiation check of the mould would immediately show whether a wire is still present.
The radiation physicist should check the inventory of radioactive sources at the end of each working day, and the source records updated accordingly.
pdf Brachytherapy – Loss of an iridium wire (Report No. 2) (70 kB)
- Details
- Parent Category: Reports - Medical and Veterinary
- Category: Brachytherapy
- Also available:
- France
pdf Brachytherapy – Loss of an iridium wire (Report No. 1) (76 kB)
Description of the incident
In a hospital brachytherapy department, five iridium-192 wires were being removed from a patient (after being placed for 5 days), when it was discovered that one of the wires was missing. It was a soft, 7 cm long wire; 37 MBq/cm (259 MBq total activity).
A search was undertaken using a radiation meter: first in the patient’s bed, then in his room, and then throughout the department until it was eventually found in a soiled clothing bag just prior to its departure for the laundry. The wire was immediately placed in storage by the physicist who was also the person competent in radiation protection.
Following this incident, regular meetings on radiation protection between relevant personnel were introduced, and a written procedure for dealing with incidents was produced.
Radiological consequences
Only one person was exposed (a nurse’s aide). She was irradiated during the replacement of the pillow case on which the iridium wire fell. The dose received by the whole body was estimated to be 35 µSv, assuming that the person was exposed for a period of one hour at one metre.
Lessons to be learned from the incident
The method of fastening the iridium could be improved. In the past, the fastening was a simple clamping technique (wire clamped at one end), whereas now double-clamping is used (wire clamped at both ends).
Where the treatment lasts several days, daily verification of the presence of each wire is necessary.
The presence of a fixed radiation detector at the exit to the brachytherapy area would have prevented this incident.
The nurse’s aide was not wearing a dosemeter, even though this was a requirement of the job. If the nurse’s aide had worn a real-time dosimeter (also a requirement in this case) she would have immediately noticed the presence of iridium wire in the pillowcase.
It is essential that all staff involved, including nurse’s aides, receive appropriate training in radiation protection. Also, short-notice replacement of staff, with people who have received no training in radiation protection, should not be allowed in this type of department.
The procedures to be followed in case of an incident must be effectively distributed (and should be specific to each department, and include the person competent in radiation protection).
pdf Brachytherapy – Loss of an iridium wire (Report No. 1) (76 kB)