ASN Report 2018

Pulsed dose-rate brachytherapy offers a number of advantages with regard to radiation protection: ∙ ∙ no handling of sources; ∙ ∙ no continuous irradiation, which enables the patient to receive medical care without irradiating the staff or having to interrupt the treatment. However, it is necessary to make provisions for accident situations related to the operation of the source afterloader and to the high dose-rate delivered by the sources used. 3.1.3  –  High Dose‑Rate (HDR) brachytherapy ∙ ∙ delivering dose-rates in excess of 12 Gy/h; ∙ ∙ using sources of iridium-192 displaying a maximum activity of 370 GBq and implemented with a specific afterloader (some afterloaders use a high-activity cobalt-60 source {91 GBq}). This technique does not require the patient to be hospitalised in a room with radiological protection; it is performed on an out-patient basis in a room with a configuration comparable to that of an external-beam radiotherapy room. The treatment is performed with an afterloader containing the source and involves one or more sessions lasting a few minutes, spread over several days. High dose-rate brachytherapy is used mainly for gynaecological cancers. This technique can also be used to treat prostate cancers, and can be combined with an external beam radiotherapy treatment. 3.2  ̶  Technical rules applicable to brachytherapy installations The rules for radioactive source management in brachytherapy are comparable to those defined for all sealed sources, regardless of their use. • Low Dose-Rate brachytherapy In cases where permanent implant techniques are used (seeds of iodine-125 in particular for treating prostate cancer), the applications are carried out in the operating theatre with ultrasonography monitoring, and do not require hospitalisation in a room with radiation protection. • Pulsed Dose-Rate brachytherapy This technique uses source afterloaders (generally 18.5 GBq of iridium-192). The treatment takes place in hospital rooms with radiological protection appropriate for the maximum activity of the radioactive source used. • High Dose-Rate brachytherapy As the maximum activity used is high (370 GBq of iridium-192 or 91 GBq of cobalt-60), irradiation can only be carried out in a room with a configuration comparable to that of an external-beam radiotherapy room. 3.3  ̶  Radiation protection situation in brachytherapy In the same way as for external-beam radiotherapy, the safety of brachytherapy treatments has been a priority area of ASN oversight since 2007. In addition, because high-activity radioactive sources are used, the questions of the management of these sources and of potential emergency situations associated with their use must also be taken into account. En 2017, 23 centres practising brachytherapy were inspected (representing 36% of the centres). 21 centres were inspected in 2018, meaning that about two-thirds of the brachytherapy departments have been inspected in two years. 3.3.1  –  Radiation protection of workers The occupational radiation protection measures deployed in 2018 by the brachytherapy departments were considered satisfactory on the whole: ∙ ∙ All the inspected centres have designated a Radiation Protection Expert-Officer (RPE-O) dedicated to this activity with defined duties. ∙ ∙ The majority of the centres inspected have drawn up the technical programme of internal and external radiation protection controls. Progress with respect to 2017 has been observed insofar as these controls have been carried out at the required frequency; Distribution of brachytherapy centres and high-dose rate brachytherapy centres inspected by ASN in 2018 0 2 4 6 8 10 12 14 Strasbourg Division Paris Division Orléans Division Nantes Division Marseille Division Lyon Division Lille Division Dijon Division Châlons-en- Champagne Division Caen Division Bordeaux Division Authorised centres High-dose rate centres Authorisations Diagram 7 ASN report on the state of nuclear safety and radiation protection in France in 2018  213 07 – MEDICAL USES OF IONISING RADIATION 07