[Image-guided radiotherapy: Overview of devices and practice in France in 2015]

Image-guided radiation therapy consists in acquiring in-room images to improve patient and mainly tumour set up accuracy. Many devices based on ionising or non-ionising radiations were designed in recent years. The use of such devices is of major importance in the management of patient radiotherapy courses. Those imaging sessions require to clearly define procedures in each radiotherapy department (image modality, acquisition frequency, corrective action, staff training and tasks). A quick review of the different existing image-guided radiation therapy devices is presented. In addition, the results of a French national survey about image-guided radiation therapy are presented: the survey is about both equipment and procedures. A total of 57 radiotherapy departments have participated, representing more than 160 treatment devices. About three linear accelerators out of four are equipped with an image-guiding device. The most common equipment is the CBCT system. Most centres have set up training sessions for the technicians to allow them to analyse online daily images. The management of in-room imaging dose is still under investigation, but many centres use an accounting scheme. While the devices are used to adjust the positioning of patients, in more than half of the centres, the practice had an impact on the choice of clinical and planning target volume margins. This survey led to an inventory in 2015, and could be renewed in some years.