Adaptive radiotherapy is a radiotherapy modality in which the treatment plan is adapted in real time, at each session, in function of the changes in position, shape, or volume of the tumor and organs at risk.
Adaptive radiotherapy offers the possibility to adapt the patient’s treatment plan in real time during the session and between sessionsby taking into accountthe variations in position,shape,or volume of:
- the tumor
- organs at risk
Adaptive radiotherapy allowscalculating the optimal dose to be delivered before each session on the basis of the real-time imaging data that show the possible changes in the position of the tumor and adjacent organs.
In standard radiotherapy linear accelerators, the treatment plan may be adapted only once or twice during the entire treatment. This is done by performing a new simulation scan on which the target volume and the organs at risk are delineated again (e.g. in the case of tumor volume decrease during treatment or of weight loss by the patient). Conversely, the new adaptive radiotherapy technologies allow calculating the optimal dose every day using treatment planning systems directly integrated in the radiotherapy devices. Specifically, the volumes of the tumor and organs at risk are delineated again on the images obtained using the on-board imaging systems (Cone Beam Computed Tomography for “conventional” linear accelerators or MRI for MRI-guided linear accelerators) to target irradiation to the tumor and to protect the surrounding tissues.