Quarterly report of ASN/SFRO level 1 radiotherapy events reported during first quarter 2009

 
Since 1 July 2008, events classified as level 1 on the ASN/SFRO scale are summarized in a general quarterly report that ASN (French Nuclear Safety Authority) publishes on its website.
 
Between 1 January and 31 March 2009, 17 events were classified as level 1 on the ASN/SFRO scale. These events, not expected to have health consequences for the patients, are nonetheless analysed for lessons learnt (particularly in terms of organisation) and to ensure they do not reoccur.

• All events reported for this period only concerned one patient, in the case of each event, and most (14 cases) took place during a single treatment session.
• More than half the events (10 cases) involved an irregularity in the patient's positioning due to use of inappropriate data or reference points or, for a specific treatment technique, to the fact that the patient's breathing was not used to automatically control the treatment beam.
• Three reports involved a beam shaping error (in particular, an error during mask production).
• One event involved a treatment session using the data for another patient treated for the same location.
• Three cases mainly involved the delivery of an inappropriate dosage due to a table height error (two events) or the use of data from the previous treatment phase.

 
Level 1 events are the subject of ASN investigations, either as part of specific enquiries, or during the annual inspection conducted by the ASN in all radiotherapy centres. The ASN systematically examines the corrective measures proposed after the centre's analysis of the event.
The corrective measures for the period in question included the following: integrating the treatment table position in the software used for verification and recording treatment parameters; redefining the naming system for the beams; and including a photo or diagram of the treatment areas in the patient file or even in the treatment room.
 
•    Consulting the ASN/SFRO scale