Reducing Risks from Sources in Medical Uses

 

Lessons to be learned

The following are but a few of the accidents that have occurred in the last 20 years, where lapses in good practice, human error, or lack of knowledge have resulted in serious injuries and deaths. A review of the root causes of these accidents reveals a worrying similarity.

Severe radiation accident in Turkey

In 1993 in Ankara, Turkey, three disused cobalt-60 teletherapy sources were packaged for re-export to the United States. The sources were not exported immediately, but were stored without the permission of the regulatory authority at the company’s premises. Over time, two of these packages were taken to Istanbul and eventually transferred to empty premises that were not secure.

In November 1998, these premises were sold, and the new owners sold the packages as scrap metal to two brothers. By December 1998, the brothers had taken the packages to the family home and over a period of a few days began dismantling the protective containers, until they and others became ill with nausea and vomiting. At some point, pieces of the dismantled containers and at least one unshielded source were apparently left in a residential area before being taken to a local scrapyard.

By the time doctors suspected exposure to radiation, and not food poisoning, was the cause of the illnesses, a total of 18 persons were admitted to hospital. Ten of these persons had symptoms of severe radiation syndrome. Five of these had to be hospitalized for 45 days. Authorities recovered one source at the scrapyard before it was melted down. The second source, reported to be in one of the packages, has not been recovered to this day.

Inadequate security over the sources and inadequate periodic inventory checks of the waste packages were the main contributing factors that allowed the unauthorized sale to take place. Lack of recognition of the trefoil symbol on the source by those trying to dismantle the source was also an important factor in the number of persons affected by this accident.

Improper waste management of the sources once they become disused was the root cause of the problem.


Multiple deaths in Thailand

In February 2000, a serious accident in Samut Prakarn, Thailand resulted in death, injury, and widespread concern. A disused cobalt-60 teletherapy source was being stored, apparently without knowledge or permission of the regulatory authority, in insecure outdoor premises normally used for storing new cars. Two local scrap collectors allegedly bought some scrap including the source and took it home to dismantle and resell.

They later took the partially dismantled teletherapy head to a junkyard where an employee cut open the protective shielding with an oxyacetylene torch. Those who had been nearby when the protective shielding was cut began to experience nausea and vomiting. Those who had touched some parts of the exposed metal began to suffer burn-like injuries. The symptoms worsened over a period of days. It was not until about 10 days later that some began to seek medical treatment for their symptoms.

By the time medical authorities reported their suspicions about a radiation accident, approximately 17 days had passed. This accident resulted in radiation injuries to 10 people of whom three died within the first two months despite medical treatment. Approximately 1870 individuals living within 100 metres of the junkyard were exposed, with many seeking medical attention. The Ministry of Health is monitoring about 258 of these individuals who live within 50 metres of the junkyard for long term health effects from the accident.

Investigation revealed that the root cause of the accident was the failure of the party responsible for the disused source to keep it securely stored. However, as in previous examples, had those who acquired the teletherapy head recognized the radiation symbol (trefoil), they might not have tried to dismantle it and would have not been exposed to radiation.



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Damaged teletherapy heads (IAEA).

 

 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 


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