前列腺癌根治术后三维适形放疗剂量学研究

目的:应用三维适形放射治疗计划系统评价前列腺癌术后不同照射方式的靶区和危及器官剂量分布差别,明确三维适形放射治疗(3-DCRT)在前列腺癌术后放疗中的优势。方法:选取2007年前列腺癌术后放疗患者10例,采用三维适形放射治疗计划系统对常规四野、四野适形和六野适形3种不同放射治疗技术设计治疗计划,比较各方法靶区和正常组织受照射剂量差异。结果:3种治疗计划均能满足靶区剂量要求,六野和四野适形放疗计划靶区剂量明显优于常规放射治疗(P<0.05)。四野和六野适形放疗较常规放疗直肠、膀胱剂量明显降低(P<0.05)。六野适形的股骨头剂量较四野适形和常规放疗明显降低(P<0.05),提示六野适形对保护股骨头具有优势。结论:前列腺癌术后放疗的常规设野方法基本能满足靶区剂量学要求,但正常组织的受照剂量明显高于3-DCRT。3-DCRT的主要优势在于减少正常组织的受照射剂量,使靶区剂量分布更合理。六野适形放疗除降低股骨头剂量外,靶区、膀胱和直肠剂量与四野适形放疗之间无显著性差异。

Dosimetric study of 3-DCRT for prostate cancer after radical prostatectomy

Objective:To assess the radiotherapy technique for prostate cancer after radical prostatectomy by using three-dimensional treatment plan system,and identify the preponderance of three-dimension conformal radiotherapy(3D-CRT) after prostatectomy.Methods:Ten patients after prostatectomy in 2007 were selected.Conventional planning,conformal planning with four fields and six fields were designed for each patient using 3D-CRT planning system,and the dosage in target areas and that in normal tissues were compared.Results:All of the three designs could meet the demands of target volume,but the conformal planning with six fields and four fields was better than the conventional planning with four fields.The dosage of rectal and bladder were significantly reduced in conformal planning with four fields and six fields compared with conventional planning(P<0.05).Comparing with conventional planning and conformal planning with four fields,the dosage of femoral head were significantly reduced in conformal planning with six fields(P<0.05).Conclusion:Conventional radiotherapy planning was able to meet demands of dosimetric requirement for radiation of prostate cancer after radical prostatectomy,while the radiation dosage of normal tissues using the conventional planning was much higher than that using the other two 3D-CRT plans.Aside from low dosage of femoral head,there were no significant differences of the dosage of target,rectal and bladder between the conformal planning with six fields and the conformal planning with four fields.