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目的:探讨三维适形和调强放疗对直肠癌放疗的物理计划特点。方法:选取5例直肠癌病例,进行CT扫描、靶区勾画和三维图像结构重建,分别在Cadplan治疗计划系统上进行三维适形和空间等分的3、5、7、9野的调强放疗计划设计,并对每一计划作出评价。结果:(1)三维适形放疗计划可满足计划靶体积(PTV)剂量要求,但重要器官的剂量分布较差。(2)4个调强放疗计划的PTV和重要器官剂量学参数均优于三维适形放疗计划,差异有统计学意义(P均<0.05),调强放疗计划间各项参数相互比较差异无统计学意义(P均>0.05)。结论:调强放疗在对直肠癌的放疗中较三维适形放疗有剂量分布的优越性。3野的调强放疗基本可以满足PTV和重要器官的剂量学要求,5野的调强放疗计划最优,7野和9野的调强放疗计划未能显示剂量学的优越性。
Objective: To investigate the physical planning of radiotherapy for rectal cancer by three-dimensional conformal and intensity-modulated radiotherapy. Methods: Five cases of rectal cancer were selected for reconstruction of CT scan, target area and three-dimensional image reconstruction. Three-dimensional conformal and spatially divided three, five, seven and nine fields of IMRT were performed on the Cadplan treatment planning system respectively Plan the design and evaluate each plan. Results: (1) Three-dimensional conformal radiotherapy plan can meet the planned target volume (PTV) dose requirements, but the vital organs dose distribution is poor. (2) The PTV and vital organs dosimetry parameters of four IMRT programs were better than the three-dimensional conformal radiotherapy plan, the difference was statistically significant (P all <0.05), the parameters of IMRT were no difference compared with each other Statistical significance (P> 0.05). CONCLUSION: IMRT has the advantage of dose distribution over three-dimensional conformal radiotherapy in radiotherapy of rectal cancer. 3 wild IMRT can basically meet the dose requirements of PTV and vital organs, 5 wild IMRT plan optimal, 7 wild and 9 wild IMR programs failed to show the superiority of dosimetry.