8. Conclusion

IGRT/ART is essential to ensure high-quality irradiation and guarantee both high local control and minimal toxicity. There can be no single recommendation, as the diversity of radiotherapy equipment and clinical situations requires adaptation to the technical environment and weighting of the level of control according to the tumor site. The additional cost in terms of manpower, equipment and dose will have to be assessed, but the benefit of IGRT currently appears indisputable, even in the absence of formal proof in randomized trials testing the use of IGRT versus an abstention from IGRT, which would no longer appear ethical. Technological developments in in vivo dosimetry and proton imaging are underway and look promising.