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
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摘要
目的:比较不同放疗技术及膀胱充盈状态对宫颈癌术后放疗靶区剂量的分布及正常组织受照体积的影响,探讨宫颈癌术后放疗的理想模式。方法:选择10例宫颈癌术后患者,分别进行膀胱充盈状态及排空状态下模拟CT扫描,处方剂量50 Gy,分别制定双弧快速旋转调强计划(RapidArc)及7野调强适形计划(IMRT)。计划的实施均为Varian公司的TrueBeam直线加速器。利用每个计划的剂量一体积直方图(DVH)进行数据分析。结果:膀胱充盈状态下IMRT及RapidArc的靶区均匀性指数分别为1.05及1.04(P>0.05),膀胱排空状态下IMRT及RapidArc的靶区均匀性指数均为1.04(P>0.05)。膀胱充盈状态下,IMRT及Rapi dArc的靶区适形度指数分别为0.71及0.73(P>0.05)。膀胱排空状态下,IMRT及RapidArc的靶区适形度指数分别为0.71及0.73(P>0.05)。小肠及膀胱接受30 Gy及40 Gy剂量的体积,膀胱充盈状态下优于膀胱排空状态,两种技术间无显著性差异。直肠及膀胱接受30 Gy剂量的体积IMRT优于RapidArc。RapidArc在治疗时间及机器跳数上明显优于IMRT。结论:7f-IMRT及双弧RapidArc在靶区适形度及均匀性方面无显著性差异;无论何种技术,膀胱充盈状态对小肠及膀胱的保护均优于膀胱排空状态;在直肠及膀胱的保护方面均优于,在机器跳数及治疗时间上优于IMRT。
Objective:To evaluate the performance of RapidArc technique on cervical cancer patients with various filling status of the bladder.Methods:Conventional fixed field intensity modulation radiated therapy(IMRT) is used as the benchmark.In 10 females suffering from cervical cancer,two CT scans were performed for treatment planning:one with an empty bladder and the other with filled bladder.The prescribed dose was 50 Gy.The images of that with an evacuated bladder and that with filled bladder were planned in the dual-arc RapidArc and the 7-field IMRT,respectively.The implementor of the plan was the Varian TrueBeam linear accelerator.Dose-volume histogram was used to evaluate the data from each plan.Results:When the bladder was filled,IMRT and RapidArc homogeneity were 1.05 and 1.04(P>0.05),respectively.When the bladder was emptied,the homogeneity was 1.04 for both plans(P>0.05).With or without bladder filling,the conformity index was 0.71 and 0.73 for IMRT and RapidArc(P>0.05),respectively.The effect of V30 and V40(volume for receiving doses of 30 and 40 Gy) on the intestine and the bladder was more favorable in a full than in an empty bladder.No significant difference between the two plans was observed.IMRT exhibited improved V30 on the rectum and on the bladder.RapidArc was much better in terms of monitor unit(MU) and deliver time.Conclusion:No significant differences in the homogeneity and conformity index between dual-arc RapidArc and 7-field IMRT were observed.Filled bladder is better than empty bladder in intestine and bladder protection in both RapidArc and IMRT.IMRT is better on V30 of the rectum and the bladder,whereas RapidArc improved MU and deliver time.
Objective:To evaluate the performance of RapidArc technique on cervical cancer patients with various filling status of the bladder.Methods:Conventional fixed field intensity modulation radiated therapy(IMRT) is used as the benchmark.In 10 females suffering from cervical cancer,two CT scans were performed for treatment planning:one with an empty bladder and the other with filled bladder.The prescribed dose was 50 Gy.The images of that with an evacuated bladder and that with filled bladder were planned in the dual-arc RapidArc and the 7-field IMRT,respectively.The implementor of the plan was the Varian TrueBeam linear accelerator.Dose-volume histogram was used to evaluate the data from each plan.Results:When the bladder was filled,IMRT and RapidArc homogeneity were 1.05 and 1.04(P>0.05),respectively.When the bladder was emptied,the homogeneity was 1.04 for both plans(P>0.05).With or without bladder filling,the conformity index was 0.71 and 0.73 for IMRT and RapidArc(P>0.05),respectively.The effect of V30 and V40(volume for receiving doses of 30 and 40 Gy) on the intestine and the bladder was more favorable in a full than in an empty bladder.No significant difference between the two plans was observed.IMRT exhibited improved V30 on the rectum and on the bladder.RapidArc was much better in terms of monitor unit(MU) and deliver time.Conclusion:No significant differences in the homogeneity and conformity index between dual-arc RapidArc and 7-field IMRT were observed.Filled bladder is better than empty bladder in intestine and bladder protection in both RapidArc and IMRT.IMRT is better on V30 of the rectum and the bladder,whereas RapidArc improved MU and deliver time.
引文
1 殷蔚伯,余子豪,徐国镇,主编.肿瘤放射治疗学[M].北京:中国协和医科大学出版社,2008:1007-1019.
2 Chang WC,Li CH,Huang SC,et al.Clinical significance of regula tory T cells and CD8+effector populations in patients with human endometrial carcinoma[J].Cancer,2010,116(24):5777-5788.
3 Foldert MR,Shih KK,Abu-Rustum NR,et al.Postoperative pelvic intensity-modulated radiotherapy and concurrent chemothera py in intermediate-and high-risk cervical cancer[J].Gynecol On col,2013,128(2):288-293.
4 Ezzell GA,GaNin JM,Low D,et al.Guidance document on deliv ery,treatment planning,and clinical implement of IMRT:report of the IMRT subcommittee of the AAPM radiation therapy committee[J].Med Phys,2003,30(8):2089-2115.
5 Liu HH,Wang XC,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.
6 Van't Riet A,Mak AC,Moerland MA,et al.A conformation num ber to quantify the degree of conformality in brachytherapy and ex ternal beam irradiation:application to the prostate[J].Int J Radiat Oncol Biol Phys,1997,37(3):731-736.
7 Bragg CM,Conway J,Robinson MH.The role of intensity-modu lated radiotherapy in the treatment of parotid tumors[J].Int J Radi at Oneol Biol Phys,2002,52(3):729-738.
8 Portelancel,Chao KS,Grigsby PW,et al.Intensity-modulated radi ation therapy(IMRT)reduces small bowel,rectum,and bladder dos es in patients with cervical cancer receiving pelvic and para-aortic irradiation[J].Int J Radiat Oncol Biol Phys,2001,51(1):261-266.
9 Heron DE,Gerszten K,Selvaraj RN,et al.Conventional 3D confor mal versus intensity-modulated radiation therapy for the adjuvant treatment of gynecologic malignancies:a comparative dosimetric study of dose volume histograms[J].Gynecol Oncol,2003,91(1):39 -45.
10 Roeske JC,Lujan A,Rotmensch J,et al.Intensity-modulated whole pelvis radiation therapy in patients with gynecologic malignancies[J].Int J Radiat Oncol Biol Phys,2000,48(5):1613-1621.
11 Mundt AJ,Mell LK,Roeske JC,et al.Preliminary analysis of chron ic gastrointestinal toxicity in gynecologic patients treated with inten sity-modulated whole pelvic radiation therapy[J].Int J Radiat On col Biol Phys,2003,56(5):1354-1360.
12 Oliver M,Ansbacher W,Beckham WA,et al.Comparing planning time,delivery time and plan quality for IMRT,RapidArc and To motherapy[J].J Appl Clin Med Phys,2009,10(4):3068.
13 Cozzi L,Dinshaw KA,Shrivastava SK,et al.A treatment planning study comparing volumetric arc modulation with RapidArc and fixed field IMRT for cervix uteri radiotherapy[J].Radiother Oncol,2008,89(2):180-191.
14 刘翔宇,柳先锋,何亚男,等.宫颈癌放疗中的快速旋转调强计划和调强计划的比较[J].中华放射医学与防护杂志,2011,31(3):326-328.
15 蒋军,张利文,廖珊,等.宫颈癌术后旋转拉弧适形放疗和五野调强放疗计划的对比研究[J].现代医院,2012,12(7):16-18.
2 Chang WC,Li CH,Huang SC,et al.Clinical significance of regula tory T cells and CD8+effector populations in patients with human endometrial carcinoma[J].Cancer,2010,116(24):5777-5788.
3 Foldert MR,Shih KK,Abu-Rustum NR,et al.Postoperative pelvic intensity-modulated radiotherapy and concurrent chemothera py in intermediate-and high-risk cervical cancer[J].Gynecol On col,2013,128(2):288-293.
4 Ezzell GA,GaNin JM,Low D,et al.Guidance document on deliv ery,treatment planning,and clinical implement of IMRT:report of the IMRT subcommittee of the AAPM radiation therapy committee[J].Med Phys,2003,30(8):2089-2115.
5 Liu HH,Wang XC,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.
6 Van't Riet A,Mak AC,Moerland MA,et al.A conformation num ber to quantify the degree of conformality in brachytherapy and ex ternal beam irradiation:application to the prostate[J].Int J Radiat Oncol Biol Phys,1997,37(3):731-736.
7 Bragg CM,Conway J,Robinson MH.The role of intensity-modu lated radiotherapy in the treatment of parotid tumors[J].Int J Radi at Oneol Biol Phys,2002,52(3):729-738.
8 Portelancel,Chao KS,Grigsby PW,et al.Intensity-modulated radi ation therapy(IMRT)reduces small bowel,rectum,and bladder dos es in patients with cervical cancer receiving pelvic and para-aortic irradiation[J].Int J Radiat Oncol Biol Phys,2001,51(1):261-266.
9 Heron DE,Gerszten K,Selvaraj RN,et al.Conventional 3D confor mal versus intensity-modulated radiation therapy for the adjuvant treatment of gynecologic malignancies:a comparative dosimetric study of dose volume histograms[J].Gynecol Oncol,2003,91(1):39 -45.
10 Roeske JC,Lujan A,Rotmensch J,et al.Intensity-modulated whole pelvis radiation therapy in patients with gynecologic malignancies[J].Int J Radiat Oncol Biol Phys,2000,48(5):1613-1621.
11 Mundt AJ,Mell LK,Roeske JC,et al.Preliminary analysis of chron ic gastrointestinal toxicity in gynecologic patients treated with inten sity-modulated whole pelvic radiation therapy[J].Int J Radiat On col Biol Phys,2003,56(5):1354-1360.
12 Oliver M,Ansbacher W,Beckham WA,et al.Comparing planning time,delivery time and plan quality for IMRT,RapidArc and To motherapy[J].J Appl Clin Med Phys,2009,10(4):3068.
13 Cozzi L,Dinshaw KA,Shrivastava SK,et al.A treatment planning study comparing volumetric arc modulation with RapidArc and fixed field IMRT for cervix uteri radiotherapy[J].Radiother Oncol,2008,89(2):180-191.
14 刘翔宇,柳先锋,何亚男,等.宫颈癌放疗中的快速旋转调强计划和调强计划的比较[J].中华放射医学与防护杂志,2011,31(3):326-328.
15 蒋军,张利文,廖珊,等.宫颈癌术后旋转拉弧适形放疗和五野调强放疗计划的对比研究[J].现代医院,2012,12(7):16-18.