摘要
目的研究再次CT扫描定位对肺癌适形放疗靶区剂量学的影响。方法选取肺癌患者103例,所有患者用热塑体膜进行体位固定,在CT机上进行第1次CT定位扫描,图像定义为CT_1,并制定全程适形放疗计划,总剂量57～65 Gy,定义为Plan0。在放疗中剂量达37～41 Gy时的计划定义为Plan1,重新CT扫描,图像定义为CT_2,根据CT_2图像重设放疗计划定义为Plan2,剂量为23～17 Gy。将初次计划Plan1与修改计划Plan2进行拟合,得到实际治疗的拟合放疗计划Plan1+2及拟合叠加的剂量体积参数,与计划Plan0的剂量体积参数比较,分析肺的V_5、V_(20)、V_(30)、MLD,心脏的V_(30),脊髓的D_(max)等参数变化。结果 (1)再次定位CT_2图像较首次定位CT_1图像,GTV体积缩小了(70. 85±36. 5) cm^3,两者差异有统计学意义(P <0. 05);再次定位CT_2图像较首次定位CT_1图像,患侧肺体积增大了(182. 8±55. 8) cm^3,全肺体积增大了(165. 1±35. 2) cm^3,两者差异有统计学意义(P <0. 05);(2)Plan 0全肺V_5、V_(20)、V_(30)较Plan1+2差异有统计学意义(P <0. 05)。Plan 0全肺MLD、侧患肺MLD较Plan1+2分别下降了(4. 2±8. 8)%、(4. 7±10. 2)%,差异有统计学意义(P <0. 05); Plan0心脏V_(30)较Plan1+2下降了(2. 7±1. 3)%,差异有统计学意义(P <0. 05); Plan0脊髓D_(max)较Plan1+2下降了(12. 5±2. 9)%,差异有统计学意义(P <0. 05)。(3)再次CT检查后Plan 0较Plan1+2靶区缩小,相应设计计划时照射野缩小,计算的剂量分布曲线向内收,肺的受照射剂量减少。结论再次定位CT_2图像较首次定位CT_1图像肺的体积增大,肿瘤靶区体积缩小,能够减小患肺及全肺受照射剂量,减轻放疗副作用及有效保护正常器官。
Objective To study the effect of CT scan again on the dosimeter of conformal radiotherapy target in lung cancer.Methods We selected 103 patients with lung cancer and all patients were fixed with thermoplast membrane.The first CT scan was performed on the CT machine.The image was defined as CT1 and a full-fledged conformal radiotherapy was planned with a total dose of 57~65 Gy,defined as Plan0.The plan for radiation doses 37~41 Gy was defined as Plan1,a new CT scan was performed,the image was defined as CT2,and the radiotherapy plan based on CT2 image reconstruction was defined as Plan2 with a dose of 23~17 Gy.The first plan Plan1 and the second plan Plan2 was fitted to obtain the actual plan of treatment of radiotherapy plan Plan1+2 and the fitted dose volume parameters,compared with the planned Plan0 dose volume parameters,analysis of lung V 5,V 20,V 30,MLD,heart V 30,spinal D max and other parameters.Results ①Compared with CT 1 image repositioned for the first time,the volume of GTV was reduced by(70.85±36.5)cm^3 compared with that of CT1 image for the first time(P<0.05)(182.8±55.8)cm^3,and the volume of whole lung increased(165.1±35.2)cm^3,with significant difference between the two groups(P<0.05).②The differences of V 5,V 20,Statistical significance(P<0.05).Plan 0 whole lung MLD and side MLD decreased by(4.2±8.8)%and(4.7±10.2)%compared with Plan1+2,respectively(P<0.05)(2.7±1.3)%,the difference was statistically significant(P<0.05).The Dmax of Plan0 spinal cord was decreased by(12.5±2.9)%compared with Plan1+2(P<0.05).③After the CT examination again,Plan 0 was smaller than that of Plan1+2 target.The irradiation field was reduced when the corresponding design plan was calculated.The calculated dose distribution curve was inwardly taken in and the irradiation dose of the lung was reduced.Conclusion CT2 image positioning again compared with the first location of CT1 image lung volume increases,the tumor target volume reduced,can reduce the affected lung and lung irradiation dose,reduce radiation side effects and effective protection of normal organs.
作者
南征
NAN Zheng(The Fifth People's Hospital of Qinghai,Xining,810007)
出处
《实用癌症杂志》
2018年第12期2011-2013,共3页
The Practical Journal of Cancer
关键词
再次CT扫描
靶区剂量学
非小细胞肺癌
放疗治疗
Once again CT scan
Target range dosimetry
Non-small cell lung cancer
Radiotherapy
