Unintended overexposure of a patient during radiotherapy treatment at the Edinburgh Cancer Centre, in September 2015

The report of a detailed investigation of an incident involving a serious overexposure to ionising radiation for a patient undergoing radiotherapy, in September 2015.

Covering note

It is approximately ten years since I was last called upon to undertake a detailed investigation of an incident involving a serious overexposure to ionising radiation for a patient undergoing radiotherapy. That earlier investigation was the overexposure of Miss Lisa Norris at the Beatson Oncology Centre in Glasgow, who was being treated for a pineoblastoma, from which, tragically, she subsequently died at the age of only 16.

To put the incident under investigation here in context, the treatment received by Miss Norris at was a radical radiotherapy treatment, wherein the dose of radiation that she received was 58% greater than the intended dose of 30 Grays. In this case, the treatment delivered at the Edinburgh Cancer Centre ( ECC) was a palliative radiotherapy treatment for alleviation of pain and existing disability in an older patient, and the dose received was 100% greater than intended dose of 20 Grays.

In both instances, the extent of the overexposure was such that there was a significant possibility of serious harm to the patient.

Both the detail and the circumstances of these overexposures were very different. In wparticular, the Glasgow incident arose from a combination of failures in what should have been a robust quality system, whereas this investigation has concluded that the Edinburgh incident was due to a combination of errors made by individuals operating within a well established quality system.

The particular circumstances of this Edinburgh incident were that the treatment was properly prescribed in accordance with the applicable ECC treatment protocol, but errors were made in the subsequent process of planning how the prescribed treatment was to be delivered. These errors remained undetected, such that the treatment planners sent the wrong information to the radiographers who delivered the treatment. The setting used on the treatment machine was therefore twice what it should have been, and remained so for all five 'fractions' of the treatment process.

I am conscious of the potential for the content of this report to add to the concerns of those undergoing radiotherapy treatments at the ECC and elsewhere. In this regard I should note that lessons have been learned and changes implemented at the ECC, and that I have confidence in the dedication of the commitment of ECC staff to the safety of patients in their care.

I would again acknowledge the many thousands of life-saving radiotherapy treatments that are successfully prescribed, planned and delivered at the ECC and at the other radiotherapy centres in Scotland every year.

Dr Arthur M Johnston
Warranted Inspector appointed by the Scottish Ministers


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