Image-guided radiotherapy: From prepositionning to treatment delivery

We present the updated recommendations of the Société française de radiothérapie oncologique (the French society for oncology radiotherapy) on image-guided radiotherapy. The objective of image-guided radiotherapy is to account for anatomical variations of the target volume occurring between or during the irradiation fractions, such as displacements and/or deformations, so that the delivered dose corresponds to the planned dose or could be even improved. This article presents the different image-guided radiotherapy devices, their clinical use, associated quality control procedures, and quantifies the possible additional dose generated by each of them. The practical implementation of image-guided radiotherapy across various tumour sites is summarized, based on the different "RecoRad™" guideline articles. Adaptive radiotherapy strategies are then detailed, due to its complexity and its recent development. The role of radiation technologist in the practice of image-guided radiotherapy is also specified. Finally, a brief update is provided on the issue of the additional dose associated with the in-room ionizing imaging, which must be estimated.