Current status of IMRT in head and neck cancer.

Background: IMRT provides highly conformal dose distributions creating non uniform spatial intensity using different segments in the beam.

Material & Methods And Results: Different retrospective studies have shown a high capability of IMRT to treat tumours close to the base of skull. Prospective studies have shown a decrease in xerostomia compared with conventional 3D conformal treatment (3DCRT). Modulation of intensity is performed by the movement of the multileaf collimator (MLC) that can deliver the radiation in different ways, such as static field segments, dynamic field segments and rotational delivery (arc therapy and tomotherapy). There are slight differences among the different techniques in terms of homogeneity, dose conformity and treatment delivery time.

Conclusions: The best method to deliver IMRT will depend on multiple factors such as deliverability, practicality, user training and plan quality.