JLE

Bulletin du Cancer

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Image-guided radiotherapy: rational, modalities and results Volume 96, issue 1, janvier 2009

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Authors
Département de radiothérapie, centre Eugène-Marquis, avenue Bataille-Flandres-Dunkerque, 35042 Rennes, France, Laboratoire de traitement du signal et de l’image, unité Inserm 642, campus de Beaulieu, université de Rennes-I, 35042 Rennes, France, Département de radiothérapie, APHP, Inserm EMI 03.37, université Paris-XII, hôpital Henri-Mondor, 54, avenue du Maréchal-de-Lattre-de-Tassigny, 94000 Créteil, France

The objective of Image-Guided Radiotherapy (IGRT) is to take in account the inter- or/and intrafraction anatomic variations (organ motion and deformations) in order to improve treatment accuracy. The IGRT should therefore translate in a clinical benefit the recent advances in both tumor definition thanks to functional imaging, and dose distribution thanks to intensity modulated radiotherapy. The IGRT enables direct or indirect tumor visualization during radiation delivery. If the tumor position does not correspond with the theoretical location of target derived from planning system, the table is moved. In case of important uncertainties related to target deformation, a new planning can be discussed. IGRT is realized by different types of devices which can vary in principle and as well as in their implementation: from LINAC-integrated-kV (or MV)-Cone Beam CTs to helicoidal tomotherapy, Cyberknife™ and Novalis ® low-energy stereoscopic imaging system. These techniques led to a more rational choice of Planning Target Volume. Being recently introduced in practice, the clinical results of this technique are still limited. Nevertheless, until so far, IGRT has showed promising results with reports of minimal acute toxicity. This review describes IGRT for various tumor localizations. The dose delivered by on board imaging should be taken in account. A strong quality control is required for safety and proper prospective evaluation of the clinical benefit of IGRT.