ASN Report 2020

Most of the events reported in 2020 concern patient radiation protection, and the majority of them are not expected to have any clinical consequences. 65% of the events reported in 2020 were rated level 1 on the ASN‑SFRO scale. Four events were rated level 2 on the ASN‑SFRO scale. They concern two laterality (“wrong-side”) errors, one irradiation of a non-targeted area, and one overdose due to a prescription transcription error at the treatment preparation stage. Lastly, one event was rated level 3 on the on the ASN‑SFRO scale (see box above). As in the preceding years, these events always highlight organisa­ tional weaknesses concerning: ∙ the management of the movement of patients’ medical files; ∙ the validation steps, which are insufficiently explicit; ∙ the keeping of patients’ files in a manner that provides an overall view and gives access to the necessary information at the right time. Variations in practices within a given centre, frequent task interruptions, a heavy and uncontrolled workload having, for example, an impact on treatment amplitudes, or the deployment of a new technique or practice, are all risk factors. Four ESRs relating to laterality errors were reported to ASN in 2020, two rated level 1 and two rated level 2 on the ASN‑SFRO scale. The level-2 events concerned errors at the target volume contouring stage, the first when treating a head and neck cancer, the second when treating a breast cancer. The following points common to these two events were noted: ∙ an error occurred at the contouring stage when a radiotherapist defined the volumes to treat; ∙ the lack of image merging between the diagnostic CT scan performed before surgical ablation of the tumour and the post- surgery CT scan in preparation for external-beam radiotherapy treatment, during the computerised operation which would have made error detection possible; ∙ the fact that the surgeon did not apply surgical clips after tumoral ablation, which would have provided a landmark; ∙ the medical file was not verified by the medical physicist at the file validation stage; ∙ the patients were not questioned on the laterality of their pathology during the first treatment sessions; ∙ the error was not detected at the medical consultations during of the treatment; ∙ the error was detected several days after the end of the treatment. SUMMARY Even though only 28% of the radiotherapy departments were inspected in 2020, and a quarter of these remotely on account of the health crisis, ASN’s radiotherapy inspections confirm that the safety fundamentals are in place (equipment verifications, medical staff training, quality and risk management policy) and the quality assurance procedures are deployed satisfactorily. The prospective risk analyses still remain relatively theoretical and are insufficiently updated prior to organisational and technical changes. Although the inspections frequencies have been reduced in response to the progress made by the radiotherapy centres, some departments presenting vulnerabilities or specific issues will continue to be subject to particular scrutiny and tighter monitoring in 2021. The inspections carried out in 2020 have shown that radiation protection conditions have significantly improved in the centres that have been served a formal compliance notice by ASN or have been subject to tightened monitoring during the preceding years. The occurrence of events such as laterality errors or fractionation errors, sometimes with serious health consequences, reveals persistent organisational weaknesses and the need to assess practices regularly. ASN Report on the state of nuclear safety and radiation protection in France in 2020 219 07 – MEDICAL USES OF IONISING RADIATION 07