Intensity-modulated arc therapy (IMAT) is an arc-based approach to intensity-modulated radiotherapy (IMRT) that can be delivered on a conventional linear accelerator using multiple overlapping arcs. As with other rotational IMRT techniques, IMAT is capable of producing highly conformal dose distributions that are able to compete with the simplest three-dimensional (3D) conformal radiotherapy (CRT) and the most effective static IMRT. Despite its potential, the clini- cal application of IMAT technique has gone largely unrealized due to the lack of robust and commercially available in- verse-planning tools. To overcome this limitation, an in-house forward-planning strategy for planning the IMAT tech- nique, called intensity modulated multiple arcs (IMMA) was developed. This planning approach was implemented for lung and cranial treatments with the aim of generating superior treatment plans compared to the 3D CRT technique. Two treatments plans, on a lung and a cranial tumour respectively, were analyzed as important examples of this new approach. The IMMA plans achieve a similar coverage of the target volumes as well as the 3D CRT technique (coplanar and non- coplanar), but with a better sparing of the critical organs and a delivery efficiency that is superior to that of 3D CRT. This result changes when the comparison is made with the fixed gantry IMRT technique, since the inverse-planned (IP) treat- ments have a greater flexibility in conforming the dose to the complex targets and in controlling the dose to the critical structures. To improve the IMMA forward-planned procedure, a new IMAT-IP approach has been proposed to obtain treatment plans that approach, in term of tumour dose coverage and dose sparing of the critical organs, the plan quality reached by the IMRT technique.
- IMAT inverse-planned
- Plan comparison
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging