ASN Report 2020

3.3.4 Emergency situations and management of malfunctions One event involving the jamming of the source in a PDR applicator was reported in 2020. The event, which occurred when the manufacturer’s technician was reloading the applicator, did not lead to personnel or patient overexposure. This type of event does however provide a reminder of the need to comply with the technical requirements concerning the use of these devices, and the obligations to provide training in emergency situation management and to conduct exercises. The jamming of a source during a maintenance or quality control operation is a precursor event that could arise during a treatment, as happened in 2019. 3.3.5 Significant events in brachytherapy In 2020, 10 ESRs were reported in brachytherapy, one concerning an overdose during brachytherapy treatment of a keloid scar which was rated level 2 on the ASN‑SFRO scale (see box above). In addition, two events having occupational radiation protection consequences resulted from losses of iodine-125 seeds during treatment preparation. The analysis of these events underlines that the control of risks in brachytherapy must be based on appropriate quality controls and the implementation of organisational measures to better manage the informing of the patient, the sources and emergency situations. SUMMARY With regard to health care safety, the brachytherapy situation appears to be comparable to that of external-beam radiotherapy, but it must be pointed out that ASN could only conduct a few inspections in this area in 2020 on account of the health crisis. Occupational radiation protection and the management of high-activity sealed sources are considered satisfactory on the whole, but the standard must nevertheless be maintained through continuous training actions. In the current context, increased attention must be devoted to securing access to these sources. GRAPH 8 Percentage of conformity of the facilities concerning the management of events giving rise to corrective actions in 2020 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Reporting culture and organisation Analysis, defining corrective actions, building on lessons learned Assessing corrective action effectiveness HDR validation procedure and traceability Overdose during brachytherapy treatment of a keloid scar A patient received brachytherapy treatment for a keloid scar. The dosimetry was approved by the physician and physicist. That same day, two brachytherapy sessions were held five hours apart. A Significant Radiation Protection Event (ESR) rated level 2 on the ASN-SFRO scale was detected one month after the brachytherapy treatment, when the department physicist compared this patient’s file with a similar file. An error in the irradiation time calculation was discovered, which had led to the patient receiving slightly more than double the prescribed dose. The difference in dose results from choosing the wrong point of dose calculation, set at 1 centimetre (cm) from the catheter instead of 0.5 cm, as provided for in the treatment protocol existing in the department. The patient was informed of the treatment error and is subject to tightened medical monitoring. The centre has taken the following corrective measures for any keloid scar treatment: ཛྷ creation of a check-list for the dosimetry tasks; ཛྷ creation of a check‑list for medical validation; ཛྷ awareness-raising and training on the existing planning protocol. 222 ASN Report on the state of nuclear safety and radiation protection in France in 2020 07 – MEDICAL USES OF IONISING RADIATION