Background: Lungs and heart are the major dose-limiting organ during radiotherapy (RT) for lung cancer. This study compared Intensity-Modulated Radiotherapy (IMRT) with Volumetric Modulated Arc Therapy (VMAT) in reducing the dose to the lungs and heart.
Methods: Ten patients with localized non-small-cell lung cancer underwent computed tomography (CT). The planning target volume (PTV) was defined and the organs at risk were outlined. Five-field coplanar IMRT plans and VMAT plans were generated for each patient. The planning objectives were to minimize the lung dose and heart dose while maintaining the dose to the PTV.
Results: All IMRT plans, except for the three-field coplanar plans, improved the PTV90/V20 ratio significantly compared with the optimized 3D-CRT plan. Nine coplanar IMRT beams were significantly better than five or seven coplanar IMRT beams, with an improved PTV90/V20 ratio.
Conclusions: The results of our study have shown that VMAT can reduce the dose to the heart compared with IMRT.