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目的:研究三维适形(3D-CRT)和逆向调强(IMRT)两种计划方式在进行早期非小细胞肺癌(NSCLC)立体定向放射治疗(SBRT)的剂量学差异。方法:选取接受放射治疗的早期NSCLC患者12例,分别采用3D-CRT和IMRT技术设计SBRT治疗计划。比较两种计划方式下PTV的相关剂量学参数(CI、HI、D1%、D99%),肺、胸壁、心脏及脊髓的剂量学参数(Vx、Dmean、Dmax),以及加速器的机器跳数、治疗时间等差异。结果:在PTV相关参数比较中,3D-CRT计划的CI、HI以及D1%均差于IMRT,差异有统计学意义,P<0.05;但是两者的D99%差异无统计学意义,P>0.05。在危及器官受量的比较中,3D-CRT与IMRT计划的患侧肺V5～V40、健侧肺V5～V15、双侧肺V5～V40、胸壁V5～V40、Dmean、心脏V20～V40、Dmean及脊髓Dmax的差异均无统计学意义,P>0.05。3D-CRT计划的机器跳数及治疗时间较IMRT计划分别减少了53%和78%,P<0.05。在绝对剂量体积比较中,3D-CRT的V60～V75及V45～V60均大于IMRT,V20～V45小于IMRT,差异均无统计学意义,P>0.05。结论:IMRT计划在早期NSCLC行SBRT治疗中不具有明显的剂量学优势。考虑到IMRT实施过程的复杂性和不确定性,早期NSCLC行SBRT治疗时3D-CRT可作为首选。
OBJECTIVE: To investigate the difference in dosimetry between stereotactic radiosurgery (SBRT) and early-stage non-small cell lung cancer (NSCLC) in three-dimensional conformal 3D-CRT and IMRT planning. Methods: Twelve patients with early stage NSCLC undergoing radiotherapy were enrolled in this study. The SBRT treatment plans were designed using 3D-CRT and IMRT respectively. The dosimetric parameters (CI, HI, D1%, D99%), lung, chest wall, heart and spinal dosimetry parameters (Vx, Dmean, Dmax) and the hops of the PTV were compared between the two schedules. Treatment time and other differences. Results: In the comparison of PTV parameters, CI-HI and D1% of 3D-CRT were worse than IMRT, the difference was statistically significant, P <0.05; however, there was no significant difference between the two . Compared with the IMRT plan, 3D-CRT and IMRT planned V5 ~ V40, V5 ~ V15, V5 ~ V40, V5 ~ V40, Dmean, V20 ~ V40, Dmean And spinal Dmax were not statistically significant, P> 0.05.3D-CRT plans to reduce the number of machine hops and treatment time were 53% and 78%, respectively, IMRT plan, P <0.05. In the comparison of absolute dose volume, V60 ~ V75 and V45 ~ V60 of 3D-CRT were all larger than IMRT, and V20 ~ V45 was smaller than IMRT, the difference was not statistically significant, P> 0.05. CONCLUSIONS: The IMRT program does not have significant dosimetric advantages in early NSCLC SBRT. Given the complexity and uncertainty of the IMRT implementation, 3D-CRT may be the first choice for SBRT in early NSCLC.