【摘要】 目的:通过比较三维适形放疗(3-dimension conformal radiotherapy,3D-CRT)计划不同处方剂量的剂量学特点,探讨直肠癌术前放疗处方剂量对危及器官的影响。方法:应用PINNACLE3治疗计划系统分别对25例拟行术前放疗的直肠癌患者进行3D-CRT计划设计,比较处方剂量46、50 Gy的靶区剂量学特点以及小肠、膀胱、双侧股骨头等正常组织的受照射剂量及体积。结果:(1)处方剂量46、50 Gy均能很好满足95%等剂量曲线对100%计划靶区(Planning target volume,PTV)体积的完全覆盖,而两者CI、HIGTV、HICTV和HIPTV没有差别。(2)3D-CRT处方剂量50 Gy中小肠和膀胱的V50明显高于46 Gy中的V50;而其他指标差异无统计学意义(P>0.05)。结论:直肠癌术前放疗不同处方剂量对小肠、膀胱接受较高剂量照射的体积影响较大。更多还原

【Abstract】 Objective:To investigate the influence of different prescribed doses on organs at risk through comparing the dosimetry of 3-dimension conformal radiotherapy(3D-CRT) in preoperative rectum cancer.Methods:With the application of the treatment planning system(PINNACLE3),25 patients with preoperative rectum cancer had 3D-CRT plan which had prescribed doses of 46 Gy and 50 Gy,and the dose characteristic of target volume and the exposure doses and volume of small bowel,bladder and bilateral femoral were compared.Results:(1)The two prescribed doses showed PTV average dose evenly,which could satisfy 95% of prescribed doses for covered PTV.For 46 Gy,CI,HIGTV,HICTV and HIPTV were close to those of 50 Gy and these differences were of no significance.(2)For 46 Gy,V50 of small bowel and bladder was smaller than that of 50 Gy.These differences were significant.Conclusion:For radiotherapy of different prescribed doses before rectum cancer operation,a higher dose has greater influence on irradiated volume of small bowel and bladder.更多还原