两种算法在宫颈癌术后三维放疗中的剂量学比较
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摘要
目的:通过比较早期宫颈癌根治术后分别基于卷积叠加算法(Collapsed Cone,CC)、蒙特卡洛算法(MonteCarlo,MC)的三维适形放疗(Three Dimensional Conformal Radiotherapy,3DCRT)技术剂量学差异,探讨两种算法应用于宫颈癌术后3DCRT时,在改善靶区和减少危及器官照射方面的差异。方法:针对40例宫颈癌术后放疗患者定位图像分别设计基于CC、MC算法的3DCRT计划,并按算法将所有计划分为CC、MC组,满足90%PTV处方剂量50Gy/2Gy/25f,对比并分析两组计划靶区和危及器官(Organ at risks,OAR)的剂量学参数、剂量计算时间、机器跳数差异。结果:对于计划靶区(Plan Target Volume,PTV),CC和MC组计划的均匀性指数((Homogeneity index,HI)分别为1.10±0.01,1.11±0.01(P<0.05),适形度指数(Conformity index, CI)分别为0.65±0.08,0.67±0.08(P<0.05),CC组的D_2、D_5均小于MC组(P<0.05)。对于OAR, CC组的直肠(D_2、D_5、D_(10))、小肠(D_(mean))、全身(D_(mean))均小于MC组(P<0.05);而MC组的左侧股骨头(D_5、D_(10))、全身(V_(40)、D_5、D_(98))均小于CC组(P<0.05)。CC组剂量计算时间远少于MC组(P<0.05)。结论:在宫颈癌根治术后辅助适形放疗中,采用CC、MC两种算法计算获得的靶区和危及器官剂量体积参数均能满足临床治疗需求,但存在一定差异。CC算法在靶区均匀性、对小肠、直肠的保护和剂量计算时间方面比MC算法更有优势,且计算速度更快,而MC算法在靶区适形度和对左侧股骨头的保护方面比CC算法更有优势,两种算法在机器跳数方面无明显差异。
Objective: To explore the dosimetric differences of three dimensional conformal radiotherapy(3 DCRT) based on Collapsed Cone(CC) algorithm and Monte Carlo(MC) algorithm for early cervical carcinoma after radical surgery. Methods: According to the location images of 40 patients undergoing postoperative radiotherapy for early cervical carcinoma, the 3 DCRT plans were designed based on the CC and MC algorithms, respectively. All plans were divided into the CC group and the MC group according to the algorithm, with 90% planning target volume receiving the prescription dose of 50 Gy/2 Gy/25 f. Dosimetric parameters of target areas and organs at risk(OAR), monitor units between the two groups were compared and analyzed. Results: For plan target volume(PTV), Homogeneity index(HI) in group CC and MC were 1.10 + 0.01,1.11 + 0.01(P<0.05), respectively. Conformity index(CI)were 0.65+0.08,0.67+0.08(P<0.05), respectively. D2 and D5 in the CC group were smaller than those in the MC group. For OAR, femoral head left(D5, D10), patient(V40, D5, D98) in the MC group were smaller than those in the CC group(P<0.05).Rectum(D2, D5, D10), small bowel(Dmean) and patient(Dmean) in the CC group were smaller than those in the MC group(P<0.05). The dose calculation time in the CC group was far less than the MC group(P<0.05). Conclusion: The CC algorithm has more advantages than the MC algorithm in the target area uniformity, the protection of small bowel and rectum, and the dose calculation time. But the MC algorithm has more advantages than the CC algorithm in the target area conformability and the protection of femoral head left. The two algorithms have no obvious differences in the monitor units.
Objective: To explore the dosimetric differences of three dimensional conformal radiotherapy(3 DCRT) based on Collapsed Cone(CC) algorithm and Monte Carlo(MC) algorithm for early cervical carcinoma after radical surgery. Methods: According to the location images of 40 patients undergoing postoperative radiotherapy for early cervical carcinoma, the 3 DCRT plans were designed based on the CC and MC algorithms, respectively. All plans were divided into the CC group and the MC group according to the algorithm, with 90% planning target volume receiving the prescription dose of 50 Gy/2 Gy/25 f. Dosimetric parameters of target areas and organs at risk(OAR), monitor units between the two groups were compared and analyzed. Results: For plan target volume(PTV), Homogeneity index(HI) in group CC and MC were 1.10 + 0.01,1.11 + 0.01(P<0.05), respectively. Conformity index(CI)were 0.65+0.08,0.67+0.08(P<0.05), respectively. D2 and D5 in the CC group were smaller than those in the MC group. For OAR, femoral head left(D5, D10), patient(V40, D5, D98) in the MC group were smaller than those in the CC group(P<0.05).Rectum(D2, D5, D10), small bowel(Dmean) and patient(Dmean) in the CC group were smaller than those in the MC group(P<0.05). The dose calculation time in the CC group was far less than the MC group(P<0.05). Conclusion: The CC algorithm has more advantages than the MC algorithm in the target area uniformity, the protection of small bowel and rectum, and the dose calculation time. But the MC algorithm has more advantages than the CC algorithm in the target area conformability and the protection of femoral head left. The two algorithms have no obvious differences in the monitor units.
引文
1 刘小琴, 徐旭娟. 宫颈癌患者生活质量影响因素研究进展[J]. 实用临床护理学电子杂志, 2017, 2(16): 151-153.
2 翟振波, 张秀珍, 宋丽, 等. 腹腔镜广泛子宫切除及盆腔淋巴结清扫术治疗早期宫颈癌183例临床分析[J]. 现代肿瘤医学, 2013, 21(10): 2319-2321.
3 涂彧. 放射治疗物理学[M]. 北京: 原子能出版社, 2010, 428.
4 周正东, 宋威. Collapsed Cone 光子束剂量计算方法研究[J]. 中国生物医学工程学报, 2011, 30(6): 909-913.
5 Chetty IJ, Curran B, Cygler JE, et al. Report of the AAPM task group No. 105. Issues associated with clinical implementation of Monte Carlo-based photon and electron external beam treatment planning[J]. Med Phys, 2007, 34(12): 4818-4853.
6 廖雄飞, 黎杰, 肖明勇, 等. 笔形束和蒙特卡罗算法在放疗剂量计算中的比较研究[J]. 中华放射肿瘤学杂志, 2015, 24(4): 364-366.
7 鞠孟阳, 史玉静, 李金凯, 等. 直肠内气腔对前列腺癌放疗计划的影响[J]. 中国医学物理学杂志, 2018, 35(8): 879-884.
8 宋佳玲, 赵艳群, 肖明勇, 等. PB算法与XVMC算法在肺癌和宫颈癌中的剂量学对比[J]. 实用医学杂志, 2015, 31(9): 1467-1469.
9 王瑜, 曲雅勤, 贾晓晶, 等. 膀胱不同充盈状态下RapidArc与IMRT对早期宫颈癌靶区剂量的影响[J]. 中国肿瘤临床, 2013, 40(17): 1064-1067.
10 毛睿, 何艳芬, 齐洪志, 等. 膀胱充盈状态对宫颈癌术后调强放疗靶区和危及器官的影响[J]. 中华实用诊断与治疗杂志, 2013, 27(8): 794-796.
2 翟振波, 张秀珍, 宋丽, 等. 腹腔镜广泛子宫切除及盆腔淋巴结清扫术治疗早期宫颈癌183例临床分析[J]. 现代肿瘤医学, 2013, 21(10): 2319-2321.
3 涂彧. 放射治疗物理学[M]. 北京: 原子能出版社, 2010, 428.
4 周正东, 宋威. Collapsed Cone 光子束剂量计算方法研究[J]. 中国生物医学工程学报, 2011, 30(6): 909-913.
5 Chetty IJ, Curran B, Cygler JE, et al. Report of the AAPM task group No. 105. Issues associated with clinical implementation of Monte Carlo-based photon and electron external beam treatment planning[J]. Med Phys, 2007, 34(12): 4818-4853.
6 廖雄飞, 黎杰, 肖明勇, 等. 笔形束和蒙特卡罗算法在放疗剂量计算中的比较研究[J]. 中华放射肿瘤学杂志, 2015, 24(4): 364-366.
7 鞠孟阳, 史玉静, 李金凯, 等. 直肠内气腔对前列腺癌放疗计划的影响[J]. 中国医学物理学杂志, 2018, 35(8): 879-884.
8 宋佳玲, 赵艳群, 肖明勇, 等. PB算法与XVMC算法在肺癌和宫颈癌中的剂量学对比[J]. 实用医学杂志, 2015, 31(9): 1467-1469.
9 王瑜, 曲雅勤, 贾晓晶, 等. 膀胱不同充盈状态下RapidArc与IMRT对早期宫颈癌靶区剂量的影响[J]. 中国肿瘤临床, 2013, 40(17): 1064-1067.
10 毛睿, 何艳芬, 齐洪志, 等. 膀胱充盈状态对宫颈癌术后调强放疗靶区和危及器官的影响[J]. 中华实用诊断与治疗杂志, 2013, 27(8): 794-796.