So sánh kỹ thuật xạ trị 3D-CRT, IMRT và VMAT trong điều trị ung thư phổi sử dụng xạ trị lập thể định vị thân

Purpose: To compare the difference of dose distribution and physical characteristics on treatment plans using Three-Dimensional Conformal Radiation Therapy (3D-CRT), Intensity Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) techniques in the treatment of lung cancer using Stereotactic Body Radiation Therapy (SBRT). Materials and method: 9 lung cancer patients who previously underwent with SBRT using VMAT on TrueBeam STx linear accelerator were selected. Average CT obtained from 4 Dimension Computed Tomography Simulation (4D-CT) of patients were used to plan on Eclipse v13.6 by 3D-CRT, IMRT, and VMAT (CP and NCP) techniques. The prescription dose 48Gy in 4 was delivered for the Planning Target Volume (PTV). All plans were optimized and evaluated based on the criteria in RTOG 0915 [1]. The dose distribution of OARs in DVH (Dose Volume Histogram) and the targets at Conformity Index (CI), Gradient Index (GI), Homogeneity Index (HI), Monitor Unit (MU) were used to comparing between conformal and modulated techniques. Results: Using VMAT and IMRT, the volume conformity was better than 3D-CRT(p<0,01), reduced significant lung dose at V5 (p<0,05). VMAT improved skin dose (23%) than 3D-CRT and IMRT. However, 3D-CRT have much lower MU number than VMAT and IMRT techniques. There were no significant differences in OARs such as the heart, esophagus, spinal cord, chest wall. Conclusions: VMAT improves the treatment volume coverage and significantly reduces the lung dose volume at V5 than 3D-CRT and IMRT techniques.