Dosimetric study of optimum treatment mode applied in intensity-modulated radiotherapy for postoperative rectal cancer
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摘要:目的
探讨直肠癌术后调强放疗中治疗体位(仰卧位与俯卧位)、准直器调强方式[动态调强(SW)与静态调强(MSS)]、剂量计算算法[各向异性解析算法(AAA算法)与笔形束卷积算法(PBC算法)]、高能X射线能量(6 MV与15 MV)、放射野个数(7野与9野)以及计算网格尺寸(0.25 cm与0.50 cm)等多变量组合最佳治疗模式的剂量学特征。
方法采用控制单一变量法，分别比较6种条件(共计12个变量)对靶区和危及器官的剂量学差异。基于剂量学差异结果，比较6种条件中相对更优的6个变量串联而成的A组与相对较差的6个变量串联而成的B组对靶区和危及器官的剂量学影响。剂量学评价指标包括靶区和危及器官的剂量受量、靶区剂量适形度指数(CI)和靶区均匀性指数(HI)、机器跳数(MU)、出束时间。
结果对于多变量串联的统计学分析显示，采用俯卧位、AAA剂量算法、动态SW的多叶光栅(MLC)运动方式、15 MV的X线、0.25 cm计算网格尺寸且9野均分的6个变量串联的A组相较于采用仰卧位、PBC剂量算法、静态MSS的MLC运动方式、6 MV的X线、0.50 cm计算网格尺寸且7野均分的6个变量串联的B组，计划靶区(PTV)的平均剂量(Dmean)平均降低了1.2%, CI平均增加了10.0%, HI平均降低了30.3%; 小肠最大剂量(Dmax)平均降低了3.0%, 膀胱4 000 cm3体积对应的剂量(V40)平均降低了31.2%, 股骨头Dmax平均降低了3.6%。
结论直肠癌术后调强放疗采用俯卧位、AAA剂量算法、动态SW的MLC运动方式、15 MV的X线能量、0.25 cm计算网格尺寸和9野均分野这6个变量组成的治疗模式，是经临床剂量学证实的对直肠癌术后调强放疗的更优治疗模式。
Abstract:ObjectiveTo explore dosimetric characteristics of multivariate combination optimal treatment model such as treatment positions (supine/prone position), collimator intensification mode[multiple static segments (MSS) and sliding window (SW)], dose calculation algorithm[Anisotropic Analytical Algorithm (AAA)]and Pencil Beam Convolution (PBC), high energy X-ray (6MV and 15MV), the number of radiation fields (7 fields versus 9 fields) and the size of calculation grids (0.25 cm versus 0.50 cm) during postoperative intensity modulated radiotherapy for rectal cancer.
MethodsControlled single variable was applied to compare the dosimetric differences of these six conditions (a total of 12 variables) on target volume and most critical organs at risk. Then, based on the above results, the dosimetric effects on planning target volume and most critical organ at risk were compared between group A which was composed up of relatively superior six variables and group B which was composed up of relatively inferior six variables. The dosimetric parameters included the dose distribution of planning target volume and most critical organs at risk, conformal index (CI), homogeneity index (HI), monitor units (MU) and beam-on time.
ResultsBased on the statistical results under the influence of multiple variables, group A with prone position, AAA dose algorithm, dynamic SW multileaf collimators (MLC) motion mode, 15 MV X-ray, mesh size calculated by 0.25 cm and 9 field equipartition of 6 variables in series had 1.2% of decrease in mean dosage (Dmean), 10.0% of increase in CI, and 30.3% of decrease in planning target volume (PTV), while 3.0% of decrease in Dmax of small intestine, 31.2% of decrease in dosage for bladder volume of 4 000 cm3 (V40), and 3.6% of decrease in femoral head in maximum dosage (Dmax) when compared with group B with supine position, PBC algorithm, MSS motion mode, 6MV X-ray, 0.50 cm calculation grids and 7 fields equipartition.
ConclusionThe treatment mode of prone position, AAA algorithm, MLC motion mode of dynamic SW, 15MV X-ray, 0.25 cm calculation grids and 9 fields is supposed to be chosen as a priority for post-operative rectal cancer of intensity-modulated radiotherapy technique.
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表 1 不同治疗体位的剂量参数比较(x±s)
参数 俯卧位 仰卧位 PTV Dmean/cGy 5 029.87±18.37 5 084.92±20.18* Dmax/cGy 5 368.70±29.86 5 395.71±38.49* Dmin/cGy 3 726.51±33.25 3 878.15±16.23 CI 0.75±0.03 0.75±0.02 HI 0.08±0.01 0.09±0.01* OARs 小肠Dmax/cGy 4 930.55±53.23 4 981.48±33.46* 脊髓Dmax/cGy 3 425.65±183.55 3 620.25±203.68 膀胱V40/% 24.18±13.84 35.12±8.63* 股骨头Dmax/cGy 4 816.03±63.15 4 725.91±53.25 MU 1 180.20±20.49 1 191.40±24.98 出束时间/min 5.08±0.37 5.13±0.86 PTV: 计划靶区; OARs: 危及器官; MU: 机器跳数; Dmean: 平均剂量; Dmax: 最大剂量; Dmin: 最小剂量; CI: 适形性指数; HI: 均匀性指数; V40: 4 000 cm3体积对应的剂量。与俯卧位比较, *P < 0.05。 
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表 2 不同剂量算法的剂量参数比较(x±s)
参数 AAA算法 PBC算法 PTV Dmean/cGy 5 029.87±18.37 5 095.33±28.46* Dmax/cGy 5 368.70±29.86 5 398.05±26.55* Dmin/cGy 3 726.51±33.25 3 873.10±16.78 CI 0.75±0.03 0.74±0.02* HI 0.08±0.01 0.09±0.01* OARs 小肠Dmax/cGy 4 930.55±53.23 4 952.31±188.55* 脊髓Dmax/cGy 3 425.65±183.55 3 477.45±156.67 膀胱V40/% 24.18±13.84 29.60±7.56* 股骨头Dmax/cGy 4 816.03±63.15 4 737.23±82.13 MU 1 180.20±20.49 1 199.30±18.60 出束时间/min 5.08±0.37 5.15±0.25 AAA算法: 各向异性解析算法; PBC算法: 笔形束卷积算法。与AAA算法比较, *P < 0.05。
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表 3 SW与MSS的剂量参数比较(x±s)
参数 SW MSS PTV Dmean/cGy 5 029.87±18.37 5 068.92±41.23* Dmax/cGy 5 368.70±29.86 5 389.73±13.66* Dmin/cGy 3 726.51±33.25 3 766.54±15.91 CI 0.75±0.03 0.74±0.02* HI 0.08±0.01 0.09±0.01* OARs 小肠Dmax/cGy 4 930.55±53.23 4 986.51±53.88* 脊髓Dmax/cGy 3 425.65±183.55 3 510.31±150.30 膀胱V40/% 24.18±13.84 25.37±11.32* 股骨头Dmax/cGy 4 816.03±63.15 4 830.54±86.13 MU 1 180.20±20.49 1 099.60±45.68* 出束时间/min 5.08±0.37 4.89±0.37* SW: 动态调强; MSS: 静态调强。与SW比较, *P < 0.05。
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表 4 6 MV与15 MV的X线剂量参数比较(x±s)
参数 6 MV能量 15 MV能量 PTV Dmean/cGy 5 029.87±18.37 5 018.26±15.44* Dmax/cGy 5 368.70±29.86 5 312.42±22.98* Dmin/cGy 3 726.51±33.25 3 706.48±23.56* CI 0.75±0.03 0.76±0.02* HI 0.09±0.01 0.08±0.01* OARs 小肠Dmax/cGy 4 930.55±53.23 4 953.88±55.59 脊髓Dmax/cGy 3 425.65±183.55 3 366.74±153.96* 膀胱V40/% 24.18±13.84 22.86±10.23* 股骨头Dmax/cGy 4 816.03±63.15 4 802.01±59.24* MU 1 180.20±20.49 1 092.30±43.15* 出束时间/min 5.08±0.37 4.86±0.23* 与6 MV能量比较, *P < 0.05。
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表 5 0.25 cm与0.50 cm的计算网格尺寸参数比较(x±s)
参数 0.25 cm 0.50 cm PTV Dmean/cGy 5 029.87±18.37 5 041.66±15.68* Dmax/cGy 5 368.70±29.86 5 407.45±33.97* Dmin/cGy 3 726.51±33.25 3 846.46±51.84 CI 0.75±0.03 0.74±0.01* HI 0.08±0.01 0.09±0.01* OARs 小肠Dmax/cGy 4 930.55±53.23 4 956.81±62.12 脊髓Dmax/cGy 3 425.65±183.55 3 199.25±157.63 膀胱V40/% 24.18±13.84 25.43±12.26* 股骨头Dmax/cGy 4 816.03±63.15 4 857.34±72.15* MU 1 180.20±20.49 1 208.10±36.98* 出束时间/min 5.08±0.37 5.10±0.27* 与0.25 cm比较, *P < 0.05。
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表 6 7野与9野参数比较(x±s)
参数 7野 9野 PTV Dmean/cGy 5 029.87±18.37 5 021.75±13.18 Dmax/cGy 5 368.70±29.86 5 399.42±33.65* Dmin/cGy 3 726.51±33.25 3 918.45±52.17 CI 0.75±0.03 0.77±0.04* HI 0.09±0.01 0.08±0.01* OARs 小肠Dmax/cGy 4 930.55±53.23 4 963.21±45.89 脊髓Dmax/cGy 3 425.65±183.55 3 261.50±127.56 膀胱V40/% 24.18±13.84 21.37±9.87* 股骨头Dmax/cGy 4 816.03±63.15 4 850.80±52.64* MU 1 180.20±20.49 1 396.30±41.26* 出束时间/min 5.08±0.37 6.04±0.26* 与7野比较, *P < 0.05。
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表 7 A组与B组的剂量学参数比较(x±s)
参数 A组 B组 PTV Dmean/cGy 5 021.64±15.21 5 078.90±34.82* Dmax/cGy 5 316.92±22.85 5 498.51±46.53* Dmin/cGy 3 774.31±31.54 3 612.48±48.12 CI 0.80±0.02 0.72±0.01* HI 0.08±0.01 0.10±0.01* OARs 小肠Dmax/cGy 4 851.32±88.63 4 998.57±146.15* 脊髓Dmax/cGy 3 256.36±182.45 3 069.87±224.55 膀胱V40/% 25.21±8.36 33.07±15.32* 股骨头Dmax/cGy 4 789.13±66.15 4 963.65±78.96* MU 1 350.65±45.12 1 123.36±43.15* 出束时间/min 6.53±0.31 5.43±0.28* 与A组比较, *P < 0.05。
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[1] EZZELL G A, GALVIN J M, LOW D, et al. Guidance document on delivery, treatment planning, and clinical implementation of IMRT: report of the IMRT Subcommittee of the AAPM Radiation Therapy Committee[J]. Med Phys, 2003, 30(8): 2089-2115. doi: 10.1118/1.1591194
[2] VAN'T RIET A, MAK A C, MOERLAND M A, et al. A conformation number to quantify the degree of conformality in brachytherapy and external beam irradiation: application to the prostate[J]. Int J Radiat Oncol Biol Phys, 1997, 37(3): 731-736. doi: 10.1016/S0360-3016(96)00601-3
[3] BRAGG C M, CONWAY J, ROBINSON M H. The role of intensity-modulated radiotherapy in the treatment of parotid tumors[J]. Int J Radiat Oncol Biol Phys, 2002, 52(3): 729-738. doi: 10.1016/S0360-3016(01)02660-8
[4] LIU H H, WANG X C, DONG L, et al. Feasibility of sparing lung and other thoracic structures with intensity-modulated radiotherapy for non-small-cell lung cancer[J]. Int J Radiat Oncol Biol Phys, 2004, 58(4): 1268-1279. doi: 10.1016/j.ijrobp.2003.09.085
[5] MUNDT A J, LUJAN A E, ROTMENSCH J, et al. Intensity-modulated whole pelvic radiotherapy in women with gynecologic malignancies[J]. Int J Radiat Oncol Biol Phys, 2002, 52(5): 1330-1337. doi: 10.1016/S0360-3016(01)02785-7
[6] DRZYMALA M, HAWKINS M A, HENRYS A J, et al. The effect of treatment position, prone or supine, on dose-volume histograms for pelvic radiotherapy in patients with rectal cancer[J]. Br J Radiol, 2009, 82(976): 321-327. doi: 10.1259/bjr/57848689
[7] KIM T H, KIM D Y, CHO K H, et al. Comparative analysis of the effects of belly board and bladder distension in postoperative radiotherapy of rectal cancer patients[J]. Strahlenther Onkol, 2005, 181(9): 601-605. doi: 10.1007/s00066-005-1398-3
[8] VAN ESCH A, TILLIKAINEN L, PYYKKONEN J, et al. Testing of the analytical anisotropic algorithm for photon dose calculation[J]. Med Phys, 2006, 33(11): 4130-4148. doi: 10.1118/1.2358333
[9] ENGELSMAN M, DAMEN E M, KOKEN P W, et al. Impact of simple tissue inhomogeneity correction algorithms on conformal radiotherapy of lung tumours[J]. Radiother Oncol, 2001, 60(3): 299-309. doi: 10.1016/S0167-8140(01)00387-5
[10] SHAHINE B H, AL-GHAZI M S A L, EL-KHATIB E. Experimental evaluation of interface doses in the presence of air cavities compared with treatment planning algorithms[J]. Med Phys, 1999, 26(3): 350-355. doi: 10.1118/1.598526
[11] CAPRILE P, VENENCIA C D, BESA P. Comparison between measured and calculated dynamic wedge dose distributions using the anisotropic analytic algorithm and pencil-beam convolution[J]. J Appl Clin Med Phys, 2007, 8(1): 47-54. doi: 10.1120/jacmp.v8i1.2370
[12] FOGLIATA A, NICOLINI G, VANETTI E, et al. The impact of photon dose calculation algorithms on expected dose distributions in lungs under different respiratory phases[J]. Physics in medicine and biology, 2008, 53(9): 2375-2390. doi: 10.1088/0031-9155/53/9/011
[13] PANETTIERI V, BARSOUM P, WESTERMARK M, et al. AAA and PBC calculation accuracy in the surface build-up region in tangential beam treatments. Phantom and breast case study with the Monte Carlo code Penelope[J]. Radiother Oncol, 2009, 93(1): 94-101. doi: 10.1016/j.radonc.2009.05.010
[14] KNOOS T, CEBERG C, WEBER L, et al. The dosimetric verification of a pencil beam based treatment planning system[J]. Phys Med Biol, 1994, 39(10): 1609-1628. doi: 10.1088/0031-9155/39/10/007
[15] ASPRADAKIS M, MORRISON R, RICHMOND N, et al. Experimental verification of convolution/superposition photon dose calculations for radiotherapy treatment planning[J]. Physics in medicine and biology, 2003, 48(3): 2873-2893.
[16] BRAGG C M, WINGATE K, CONWAY J. Clinical implications of the anisotropic analytical algorithm for IMRT treatment planning and verification[J]. Radiother Oncol, 2008, 86(2): 276-284. doi: 10.1016/j.radonc.2008.01.011
[17] RØNDE H S, HOFFMANN L. Validation of Varian′s AAA algorithm with focus on lung treatments[J]. Acta Oncol, 2009, 48(2): 209-215. doi: 10.1080/02841860802287108
[18] AARUP L R, NAHUM A E, ZACHARATOU C, et al. The effect of different lung densities on the accuracy of various radiotherapy dose calculation methods: implications for tumour coverage[J]. Radiother Oncol, 2009, 91(3): 405-414. doi: 10.1016/j.radonc.2009.01.008
[19] POTTER L D, CHANG S X, CULLIP T J, et al. A quality and efficiency analysis of the IMFASTTM segmentation algorithm in head and neck "step & shoot" IMRT treatments[J]. Med Phys, 2002, 29(3): 275-283. doi: 10.1118/1.1428755
[20] KUBO H D, PAPPAS C T E, WILDER R B. A comparison of arc-based and static mini-multileaf collimator-based radiosurgery treatment plans[J]. Radiother Oncol, 1997, 45(1): 89-93. doi: 10.1016/S0167-8140(97)00104-7
[21] KULIK C, CAUDRELIER J M, VERMANDEL M, et al. Conformal radiotherapy optimization with micromultileaf collimators: comparison with radiosurgery techniques 1[J]. Int J Radiat Oncol, 2002, 53(4): 1038-1050. doi: 10.1016/S0360-3016(02)02863-8
[22] MADANI I, VANDERSTRAETEN B, BRAL S, et al. Comparison of 6 MV and 18 MV photons for IMRT treatment of lung cancer[J]. Radiother Oncol, 2007, 82(1): 63-69. doi: 10.1016/j.radonc.2006.11.016
[23] LAUGHLIN J S, MOHAN R, KUTCHER G J. Choice of optimum megavoltage for accelerators for photon beam treatment[J]. Int J Radiat Oncol, 1986, 12(9): 1551-1557. doi: 10.1016/0360-3016(86)90277-4
[24] HALL E J. Intensity-modulated radiation therapy, protons, and the risk of second cancers[J]. Int J Radiat Oncol, 2006, 65(1): 1-7. doi: 10.1016/j.ijrobp.2006.01.027
[25] AOYAMA H, WESTERLY D C, MACKIE T R, et al. Integral radiation dose to normal structures with conformal external beam radiation[J]. Int J Radiat Oncol, 2006, 64(3): 962-967. doi: 10.1016/j.ijrobp.2005.11.005
[26] WEISS E, SIEBERS J V, KEALL P J. An analysis of 6-MV versus 18-MV photon energy plans for intensity-modulated radiation therapy (IMRT) of lung cancer[J]. Radiother Oncol, 2007, 82(1): 55-62. doi: 10.1016/j.radonc.2006.10.021
[27] WELSH J S, MACKIE T R, LIMMER J P. High-energy photons in IMRT: uncertainties and risks for questionable gain[J]. Technol Cancer Res Treat, 2007, 6(2): 147-149. doi: 10.1177/153303460700600212
[28] HUQ M S, YU Y, CHEN Z P, et al. Dosimetric characteristics of a commercial multileaf collimator[J]. Med Phys, 1995, 22(2): 241-247. doi: 10.1118/1.597461
[29] KRY S F, SALEHPOUR M, FOLLOWILL D S, et al. The calculated risk of fatal secondary malignancies from intensity-modulated radiation therapy[J]. Int J Radiat Oncol, 2005, 62(4): 1195-1203. doi: 10.1016/j.ijrobp.2005.03.053
[30] CHUNG H, JIN H, PALTA J, et al. Dose variations with varying calculation grid size in head and neck IMRT[J]. Phys Med Biol, 2006, 51(19): 4841-4856. doi: 10.1088/0031-9155/51/19/008
[31] MITTAUER K, LU B, YAN G H, et al. A study of IMRT planning parameters on planning efficiency, delivery efficiency, and plan quality[J]. Med Phys, 2013, 40(6): 061704.
[32] MA H, HAN J, ZHANG T, et al. Comparison of dosiology between three dimensional conformal and intensity-modulated radiotherapies (5 and 7 fields) in gastric cancer post-surgery[J]. J Huazhong Univ Sci Technol, 2013, 33(5): 759-764. doi: 10.1007/s11596-013-1193-9
[33] 李军. 基于Varian clinac-Ⅸ直线加速器放疗系统的技术分析和临床剂量学研究[D]. 南京: 南京航空航天大学, 2016. [34] 张先稳, 李军, 张西志, 等. 宫颈癌术后5野调强放疗4个变量组合的最佳治疗模式的剂量学[J]. 中国医学物理学杂志, 2016, 33(9): 872-880. doi: 10.3969/j.issn.1005-202X.2016.09.002 [35] 李军, 陈雪梅, 张西志, 等. 宫颈癌术后常规与旋转容积调强放疗计划剂量学研究[J]. 中华肿瘤防治杂志, 2014, 21(14): 1104-1108. doi: 10.16073/j.cnki.cjcpt.2014.14.008 -
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