应用KV-X线CBCT对头颈部癌调强放疗摆位误差的测量与分析
摘要
目的探讨锥形束CT用于头颈部肿瘤调强放疗摆位误差的测量,分析调强放射治疗中误差对靶区和危及器官物理剂量学的影响。
方法应用瓦里安21EX IGRT系统治疗头颈部肿瘤患者15例,每名患者每周行KVCBCT在线引导体位校正1次,在校位前、治疗后分别行1次CBCT扫描,共计204次CBCT扫描。得到两组X线容积图像(XVI),将两组XVI图像和原计划CT图像进行匹配比较,获得两组X、Y、Z三维方向的线性误差和Z轴向旋转误差。分析摆位误差分布情况及治疗前后摆位误差的变化。在计划系统中模拟10位鼻咽癌患者治疗时的摆位误差,重新计算剂量分布,明确摆位误差对靶区和危及器官物理剂量的影响。
结果15例头颈部癌患者共进行CBCT扫描204次,CBCT图像能清楚地将软组织分辨出来,显示患者肿瘤位置、大小及周围组织器官的情况。所有摆位误差在3.00mm以内的值为514次(83.99%),在5mm以内的值为597次(94.61%)。未出现大于3°的旋转误差。在校位前X、Y、Z方向的线性摆位误差为(-0.21±1.85)mm、(-0.24±2.10)mm、(0.36±1.92)mm;治疗后分别为(-0.09±0.87)mm、(0.18±0.95)mm、(0.05±0.91)mm。Z轴向旋转误差校位前、治疗后分别为(0.37±1.35)°、(0.18±0.29)°。大部分患者治疗后的摆位系统误差(包括线性误差及旋转误差)明显低于校位前的摆位系统误差,统计结果有显著性意义,CTV到PTV以及危机器官的外放边界为:左右方向(X)3.80mm,上下方向(Y)4.20mm,前后方向(Z)3.50mm;0.3~3.5mm。3mm以内的线性摆位误差对靶区及危及器官的剂量影响小。
结论头颈部癌患者摆位重复性较好,摆位误差较小,非每日的CBCT验证可以降低系统误差和随机误差,在一定程度提高放疗的精度,同时又可以使额外照射剂量尽量减少。
Objective To measure the setup error of the intensity modulated radiation therapy for head and neck cancers by cone-beam computed tomography, and to analyze the effect of the setup error on the physics dose of targets and peripheral organs at risk of the intensity modulated radiation therapy.
Methods 15 head and neck cancer patients were treated with the Varian 21EX IGRT system, all the patients had received kilovoltage cone-beam computed tomography (KV-CBCT) weekly before correct the setup error and after radiotherapy separately for a total of 204 times.The acquired two groups of X-ray volume image(XVI) were compared to planned CT images with calculated setup errors of X-axis, Y-axis and Z-axis both of translational and Z-axis rotational errors. Then analyze distribution of setup error and the changes of setup errors before correction and after radiotherapy. Ten nasopharyngeal carcinom patients were simulated three-dimensional errors in therapy on the treatment planning system,and recalculated their dose distribution again, and obtained the impact of the setup erors on the targets and organs at risk physics dose.
Results All the 15 head and neck cancer patients received a total of 204 CBCT scans, the acquired CBCT images had a high quality clearly showing soft tissue organs, especially the tumor location, size and the surrounding structures. In less than 3mm were 514 scans(83.99%), and in less than 5.00 mm were 597 scans(94.61%) in all of setup errors. There was no greater than 3°rotational errors. The setup errors on translational X, Y, Z directions befoer the correction were (-0.21±1.8)mm,(-0.24±2.10)mm, (0.36±1.92)mm; after radiotherapy were (-0.09±0.87)mm, (0.18±0.95)mm, (0.05±0.91)mm. The Z-axis rotational errors befoer the correction and after radiotherapy were (0.37±1.35)°, ( 0.18±0.29)°. Most of setup errors after radiotherapy (including translational and rotational errors) less than befoer the correction obviously,having statistics signification. The CTV to PTV margins of X-axis, Y-axis, Z-axis and PORV were 3.80 mm, 4.20 mm, 3.50mm, 0.3~3.5mm, respectively. The translational errors less than 3mm effected the targets and organs at risk dose unobviously.
Conclusion Setup errors for head and neck cancer patients were good repeatability, and minor.Non-everyday CBCT scans can reduce the systematic error and random error, improve the accuracy in a certain extent and reduce the additional dose as possible.
方法应用瓦里安21EX IGRT系统治疗头颈部肿瘤患者15例,每名患者每周行KVCBCT在线引导体位校正1次,在校位前、治疗后分别行1次CBCT扫描,共计204次CBCT扫描。得到两组X线容积图像(XVI),将两组XVI图像和原计划CT图像进行匹配比较,获得两组X、Y、Z三维方向的线性误差和Z轴向旋转误差。分析摆位误差分布情况及治疗前后摆位误差的变化。在计划系统中模拟10位鼻咽癌患者治疗时的摆位误差,重新计算剂量分布,明确摆位误差对靶区和危及器官物理剂量的影响。
结果15例头颈部癌患者共进行CBCT扫描204次,CBCT图像能清楚地将软组织分辨出来,显示患者肿瘤位置、大小及周围组织器官的情况。所有摆位误差在3.00mm以内的值为514次(83.99%),在5mm以内的值为597次(94.61%)。未出现大于3°的旋转误差。在校位前X、Y、Z方向的线性摆位误差为(-0.21±1.85)mm、(-0.24±2.10)mm、(0.36±1.92)mm;治疗后分别为(-0.09±0.87)mm、(0.18±0.95)mm、(0.05±0.91)mm。Z轴向旋转误差校位前、治疗后分别为(0.37±1.35)°、(0.18±0.29)°。大部分患者治疗后的摆位系统误差(包括线性误差及旋转误差)明显低于校位前的摆位系统误差,统计结果有显著性意义,CTV到PTV以及危机器官的外放边界为:左右方向(X)3.80mm,上下方向(Y)4.20mm,前后方向(Z)3.50mm;0.3~3.5mm。3mm以内的线性摆位误差对靶区及危及器官的剂量影响小。
结论头颈部癌患者摆位重复性较好,摆位误差较小,非每日的CBCT验证可以降低系统误差和随机误差,在一定程度提高放疗的精度,同时又可以使额外照射剂量尽量减少。
Objective To measure the setup error of the intensity modulated radiation therapy for head and neck cancers by cone-beam computed tomography, and to analyze the effect of the setup error on the physics dose of targets and peripheral organs at risk of the intensity modulated radiation therapy.
Methods 15 head and neck cancer patients were treated with the Varian 21EX IGRT system, all the patients had received kilovoltage cone-beam computed tomography (KV-CBCT) weekly before correct the setup error and after radiotherapy separately for a total of 204 times.The acquired two groups of X-ray volume image(XVI) were compared to planned CT images with calculated setup errors of X-axis, Y-axis and Z-axis both of translational and Z-axis rotational errors. Then analyze distribution of setup error and the changes of setup errors before correction and after radiotherapy. Ten nasopharyngeal carcinom patients were simulated three-dimensional errors in therapy on the treatment planning system,and recalculated their dose distribution again, and obtained the impact of the setup erors on the targets and organs at risk physics dose.
Results All the 15 head and neck cancer patients received a total of 204 CBCT scans, the acquired CBCT images had a high quality clearly showing soft tissue organs, especially the tumor location, size and the surrounding structures. In less than 3mm were 514 scans(83.99%), and in less than 5.00 mm were 597 scans(94.61%) in all of setup errors. There was no greater than 3°rotational errors. The setup errors on translational X, Y, Z directions befoer the correction were (-0.21±1.8)mm,(-0.24±2.10)mm, (0.36±1.92)mm; after radiotherapy were (-0.09±0.87)mm, (0.18±0.95)mm, (0.05±0.91)mm. The Z-axis rotational errors befoer the correction and after radiotherapy were (0.37±1.35)°, ( 0.18±0.29)°. Most of setup errors after radiotherapy (including translational and rotational errors) less than befoer the correction obviously,having statistics signification. The CTV to PTV margins of X-axis, Y-axis, Z-axis and PORV were 3.80 mm, 4.20 mm, 3.50mm, 0.3~3.5mm, respectively. The translational errors less than 3mm effected the targets and organs at risk dose unobviously.
Conclusion Setup errors for head and neck cancer patients were good repeatability, and minor.Non-everyday CBCT scans can reduce the systematic error and random error, improve the accuracy in a certain extent and reduce the additional dose as possible.
引文
[1] IMRT Collaborative Working Group.Intensity-modulated radiotherapy: current status and issues of interest.Int J Radiat Oncol Biol Phys 2 001;51:880- 914.
[2] Remeijer P,Geerlof E,Ploeger L,et al.3-D portal image analysis in clinical pratice:an evaluation of 2-D and 3-D analysis techniques as applied to 30 prostate cancer patients.Int J Radiat Oncol Biol Phy,2000,46:1281-1290.
[3] Prescribing recording and reposing photon beam therapy(Supplement to ICRU report 50) [R].ICRU.Report no.62.1999.
[4] Van Herk M. Errors and margins in radiotherapy[J]. Semin Radiat Oncol. 2004,l4:52-64
[5] McKenzie A,Van Herk M,Mijnheer B.Margins for geometric uncertainty around organs at risk in radiotherapy. Radiother Oncol,2002,62:299-307.
[6]岳金波,于金明,刘菁,等.锥形束CT测量鼻咽癌放疗计划靶区外放研究[J].中华放射肿瘤学杂志. 2007,16(3):223-224.
[7] Kim GY,Pawlicki T,Le QT,et a1. Linac-based on-board imaging feasibility and the dosimetric consequences of head roll in head-and-neck IMRT plans[J].Med Dosim.2008;33(1):93-9.
[8] Astrcinidou E ,BecA,Raaijmaker C.PJ,et a1.Adequate margins for random setup uncertainties in head-and-neck IMRT[J].Int J Radiat Oncol Biol Plays.2005;61(3):938-944.
[9] Guckenberger M,Meyer J,Vordermark D,et a1.Magnitude and clinical relevance of translational and rotational patient setup errors:a cone-beam CT study[J].Int J Radiat Oncol Biol Phys 2006;65(3):934-942.
[10] Hurkmans CW,Remeijer P,Lebesque JV,et a1.Set—up verification using portal images;review of current clinical practice [J]. Radiotherapy and Oncology,2001,58(2):105—120.
[11] Herman MG,Kruse GG,Hagness CR.Guide to clinical use of electronic portal imaging[J].J Appl Clin Med Phys,2000,1(2):38.
[12] Nielsen,Morten,Bertelsen,et al. Cone beam CT evaluation of patient set-up accuracy as a QA tool[J]. Acta Oncol. 2009, 48:271-276.
[13]许峰,柏森,王瑾,等.用锥形束CT图像测量放疗摆位误差[J].中华放射肿瘤学杂志. 2007, l6(6):461-464.
[14]王瑾,许峰,柏森,等.千伏级锥形束断层扫描在鼻咽癌适形调强放射治疗中的初步应用技术与方法[J].癌症. 2008, 27(7):761-765.
[15]郑步宏,潘建基,徐鹭英,等.垫内置标记点法测量鼻咽癌适形放疗摆位误差的研究[J].中华放射肿瘤学杂志.2005,14(3):218-221.
[16] Lawson JD,Elder E,Fox T,et a1.Quantification of Dosimetric Impact of Implementation of On-Board Imaging(OBD for IMRT Treatment of Head-And-Neck Malignancies.Med Dosim.2007;32(4):287-94.
[17] O’Daniel JC, AS Garden, DL Schwartz,et a1.Parotid gland dose in intensity-modulated radiotherapy for head and neck cancer:is what you plan what you get?[J] Int J Radiat Oncol Biol Phys.2007;69(4):1290-1296.
[18] Guckenberger M,Meyer J,Wilbeft J,et a1.Precision required for dose-escalated treatment of spinal metastases and implications for image-guided radiation therapy(IGRT)[J].Radiother Onc01.2007 Jul;84(1):56-63.
[19] Ding George X,Coffey Charles W.Radiation dose from kilovoltage cone beam computed tomography in an image-guided radiotherapy procedure[J].Int J Radiat Oncol Biol Phys,2009,73 (2):610-617.
[1]胡逸民.调强适形放射治疗.见:胡逸民,主编.肿瘤放射物理学.北京:原子能出版社.1999.538-605.
[2] Hunt MA,Zelefsky MJ,Wolden S,et al.Treatment planning and delivery of intensity-modulatedr adiation therapy for primary nasopharynx cancer.Int Radiat Oncol Biol Phs 2001;49(3):623-632.
[3] Ping X,Lee N,Liu YM,et al.A study of planning dose constraints for Treatment ofnasopharyngeal carcinoma using a commercial inverse treatment Planning system.Int Radiat Oncol Biol Phs 2004;59(3):886-896.
[4] Kam MK,Chau RM,Suen J,at aL.Intensity-modulated radiotherapy in Nasopharyngeal carcinoma:dosimetric advantage over conventional plans and feasibiilty of dose escalation.Int Radiat Oncol Biol Phs 2003;56(1):145-157.
[5] Fu WH, Wang LH, Zhou ZM, et al. Comparison of conformal and intensitymodulated techniques for simultaneous integrated boost radiotherapy of upper esophageal carcinoma [J].World J Gastroenterol , 2004,10(8):10981102.
[6] Stein J, Mohan R, Wang XH, et al. Number and orientations of beams in intensitymodulated radiation treatments [J]. Med Phys Feb,1997,24(2):149-160.
[7] EB Butler, BS Teh, WH GrantIII, BM Uhl, et al. Smart (simultaneous modulated accelerated radiation therapy) boost: a new accelerated fractionation schedule for the treatment of head and neck cancer with intensity modulated radiotherapy[J]. Int J Radiat Oncol Biol Phys, 1999,45(1):21-32.
[8]黄雄,张纬建.鼻咽癌调强放疗技术的临床应用进展[J].福建医药杂志, 2007,3:104-106.
[9]郑小康,陈龙华.三维适形放疗临床实践[M].第1版,北京:人民卫生出版社,2001.41-49.
[10] Li XA, Wang JZ, Jursinic PA, et al. Dosimetric advantages of IMRT simultaneous integrated boost for highrisk prostate cancer [J]. Int J Radiat Oncol Biol Phys, 2005, 61(4):1251-1257.
[11]袁智勇,高黎,徐国镇,等.初治鼻咽癌调强放疗的初步结果[J].中华放射肿瘤学杂志, 2006,15(4):237-243.
[12] Lee N,Xia P,Quivey J M,et al. Intensitymodulated radiotherapy in the treatment of nasopharyngeal carcinoma: an updated of the UCSF experience[J]. Int J Radiat Oncol Biol Phys, 2002,53(1):12-22.
[13] Mendenhall W M,Amdur R J,Palta J R. Intensitymodulated radiotherapy in the standard management of head and neck cancer: promises and pitfalls[J]. J Clin Oncol, 2006,24(17):2618-2623.
[14] Faivre S,Janot F,Armand J P. Optimal management of nasopharyngeal carcinoma[J]. Curr Opin Oncol, 2004,16(3):231-235.
[15] Sultanem K, Shu HK, Xia P, et al. Threedimensional intensitymodulatedradiotherapy in the treatment of nasopharyngeal carcinoma: the University of CaliforniaSan Francisco experience [ J ] . Int J Radiat Oncol Biol Phys,2000,48(3):711-722.
[16]吕庆文,陈超敏,周凌宏.一种检验X刀定位精度的方法[J].立体定向和功能性神经外科杂志,2000,(2):111.
[17]吕庆文,李光明,李树祥X刀治疗计划设计的研究[J].北京生物医学工程,20 01,(1):57.
[18] IMRT Collaborative Working Group.Intensity-modulated radiotheraphy: current status and issues of interest[ J]. Int. J. Radiation Oncology Biol.Phys. 2001,51(4):880.
[19]高磊,吕庆文,李树祥,等一种求调强放疗中最佳笔射束强度分布的改进方法[J].北京生物医学工程,1999,(3):166.
[20] Rasch C, Keus R, Pameijer FA, et al. The potential impact of CT-MRI matching on tumor volume delineation in advanced head and neck cancer[J]. Int J Radiat Oncol Biol Phys, 1997, 39(4):841-848.
[21] Emami B, Sethi A, Petruzzelli GJ. Influence of MRI on target volume delineation and IMRT planning in nasopharyngeal carcinoma[J]. Int J Radiat Oncol Biol Phys, 2003, 57(2):481-488.
[22] Nishioka T, Shiga T, Shirato H, et al. Image fusion between 18FDG-PET and MRI/CT for radiotherapy planning of oropharyngeal and nasopharyngeal carcinomas[J]. Int J Radiat Oncol Biol Phys, 2002, 53(4):1051-1057.
[23]陈波,易俊林,高黎,等.鼻咽癌IMRT靶区勾画与计划制定期间肿瘤体积的变化.中华放射肿瘤学杂志,2007,16(3):161-167.
[24]曹建忠,罗京伟,徐国镇,等.鼻咽癌调强放疗中靶区和正常器官变化规律及临床意义探讨.中华放射肿瘤学杂志,2007,16(2):81-85.
[25]郭明芳,郭雷鸣,赵娅琴,等.锥形束CT研究肺癌放射治疗中的摆位误差.中国肿瘤临床,2009,36(15):848-852.
[26] Dai JR,Hu YM;Implement of Image Guided Radiation Therapy. Chin J Radiat Oncol,2006,Vol 15,132-135.
[27] Downs,T.M.;Roach,M.;Gmssfeld,G.D.;et al.The University of California,San Francisco(UCSF)experience with permanently implanted gold markers for dailyprostate realignment during radiation therapy[J].Int. Radiat.Onco1.Bio1.Phys, 2002,54:80.
[2] Remeijer P,Geerlof E,Ploeger L,et al.3-D portal image analysis in clinical pratice:an evaluation of 2-D and 3-D analysis techniques as applied to 30 prostate cancer patients.Int J Radiat Oncol Biol Phy,2000,46:1281-1290.
[3] Prescribing recording and reposing photon beam therapy(Supplement to ICRU report 50) [R].ICRU.Report no.62.1999.
[4] Van Herk M. Errors and margins in radiotherapy[J]. Semin Radiat Oncol. 2004,l4:52-64
[5] McKenzie A,Van Herk M,Mijnheer B.Margins for geometric uncertainty around organs at risk in radiotherapy. Radiother Oncol,2002,62:299-307.
[6]岳金波,于金明,刘菁,等.锥形束CT测量鼻咽癌放疗计划靶区外放研究[J].中华放射肿瘤学杂志. 2007,16(3):223-224.
[7] Kim GY,Pawlicki T,Le QT,et a1. Linac-based on-board imaging feasibility and the dosimetric consequences of head roll in head-and-neck IMRT plans[J].Med Dosim.2008;33(1):93-9.
[8] Astrcinidou E ,BecA,Raaijmaker C.PJ,et a1.Adequate margins for random setup uncertainties in head-and-neck IMRT[J].Int J Radiat Oncol Biol Plays.2005;61(3):938-944.
[9] Guckenberger M,Meyer J,Vordermark D,et a1.Magnitude and clinical relevance of translational and rotational patient setup errors:a cone-beam CT study[J].Int J Radiat Oncol Biol Phys 2006;65(3):934-942.
[10] Hurkmans CW,Remeijer P,Lebesque JV,et a1.Set—up verification using portal images;review of current clinical practice [J]. Radiotherapy and Oncology,2001,58(2):105—120.
[11] Herman MG,Kruse GG,Hagness CR.Guide to clinical use of electronic portal imaging[J].J Appl Clin Med Phys,2000,1(2):38.
[12] Nielsen,Morten,Bertelsen,et al. Cone beam CT evaluation of patient set-up accuracy as a QA tool[J]. Acta Oncol. 2009, 48:271-276.
[13]许峰,柏森,王瑾,等.用锥形束CT图像测量放疗摆位误差[J].中华放射肿瘤学杂志. 2007, l6(6):461-464.
[14]王瑾,许峰,柏森,等.千伏级锥形束断层扫描在鼻咽癌适形调强放射治疗中的初步应用技术与方法[J].癌症. 2008, 27(7):761-765.
[15]郑步宏,潘建基,徐鹭英,等.垫内置标记点法测量鼻咽癌适形放疗摆位误差的研究[J].中华放射肿瘤学杂志.2005,14(3):218-221.
[16] Lawson JD,Elder E,Fox T,et a1.Quantification of Dosimetric Impact of Implementation of On-Board Imaging(OBD for IMRT Treatment of Head-And-Neck Malignancies.Med Dosim.2007;32(4):287-94.
[17] O’Daniel JC, AS Garden, DL Schwartz,et a1.Parotid gland dose in intensity-modulated radiotherapy for head and neck cancer:is what you plan what you get?[J] Int J Radiat Oncol Biol Phys.2007;69(4):1290-1296.
[18] Guckenberger M,Meyer J,Wilbeft J,et a1.Precision required for dose-escalated treatment of spinal metastases and implications for image-guided radiation therapy(IGRT)[J].Radiother Onc01.2007 Jul;84(1):56-63.
[19] Ding George X,Coffey Charles W.Radiation dose from kilovoltage cone beam computed tomography in an image-guided radiotherapy procedure[J].Int J Radiat Oncol Biol Phys,2009,73 (2):610-617.
[1]胡逸民.调强适形放射治疗.见:胡逸民,主编.肿瘤放射物理学.北京:原子能出版社.1999.538-605.
[2] Hunt MA,Zelefsky MJ,Wolden S,et al.Treatment planning and delivery of intensity-modulatedr adiation therapy for primary nasopharynx cancer.Int Radiat Oncol Biol Phs 2001;49(3):623-632.
[3] Ping X,Lee N,Liu YM,et al.A study of planning dose constraints for Treatment ofnasopharyngeal carcinoma using a commercial inverse treatment Planning system.Int Radiat Oncol Biol Phs 2004;59(3):886-896.
[4] Kam MK,Chau RM,Suen J,at aL.Intensity-modulated radiotherapy in Nasopharyngeal carcinoma:dosimetric advantage over conventional plans and feasibiilty of dose escalation.Int Radiat Oncol Biol Phs 2003;56(1):145-157.
[5] Fu WH, Wang LH, Zhou ZM, et al. Comparison of conformal and intensitymodulated techniques for simultaneous integrated boost radiotherapy of upper esophageal carcinoma [J].World J Gastroenterol , 2004,10(8):10981102.
[6] Stein J, Mohan R, Wang XH, et al. Number and orientations of beams in intensitymodulated radiation treatments [J]. Med Phys Feb,1997,24(2):149-160.
[7] EB Butler, BS Teh, WH GrantIII, BM Uhl, et al. Smart (simultaneous modulated accelerated radiation therapy) boost: a new accelerated fractionation schedule for the treatment of head and neck cancer with intensity modulated radiotherapy[J]. Int J Radiat Oncol Biol Phys, 1999,45(1):21-32.
[8]黄雄,张纬建.鼻咽癌调强放疗技术的临床应用进展[J].福建医药杂志, 2007,3:104-106.
[9]郑小康,陈龙华.三维适形放疗临床实践[M].第1版,北京:人民卫生出版社,2001.41-49.
[10] Li XA, Wang JZ, Jursinic PA, et al. Dosimetric advantages of IMRT simultaneous integrated boost for highrisk prostate cancer [J]. Int J Radiat Oncol Biol Phys, 2005, 61(4):1251-1257.
[11]袁智勇,高黎,徐国镇,等.初治鼻咽癌调强放疗的初步结果[J].中华放射肿瘤学杂志, 2006,15(4):237-243.
[12] Lee N,Xia P,Quivey J M,et al. Intensitymodulated radiotherapy in the treatment of nasopharyngeal carcinoma: an updated of the UCSF experience[J]. Int J Radiat Oncol Biol Phys, 2002,53(1):12-22.
[13] Mendenhall W M,Amdur R J,Palta J R. Intensitymodulated radiotherapy in the standard management of head and neck cancer: promises and pitfalls[J]. J Clin Oncol, 2006,24(17):2618-2623.
[14] Faivre S,Janot F,Armand J P. Optimal management of nasopharyngeal carcinoma[J]. Curr Opin Oncol, 2004,16(3):231-235.
[15] Sultanem K, Shu HK, Xia P, et al. Threedimensional intensitymodulatedradiotherapy in the treatment of nasopharyngeal carcinoma: the University of CaliforniaSan Francisco experience [ J ] . Int J Radiat Oncol Biol Phys,2000,48(3):711-722.
[16]吕庆文,陈超敏,周凌宏.一种检验X刀定位精度的方法[J].立体定向和功能性神经外科杂志,2000,(2):111.
[17]吕庆文,李光明,李树祥X刀治疗计划设计的研究[J].北京生物医学工程,20 01,(1):57.
[18] IMRT Collaborative Working Group.Intensity-modulated radiotheraphy: current status and issues of interest[ J]. Int. J. Radiation Oncology Biol.Phys. 2001,51(4):880.
[19]高磊,吕庆文,李树祥,等一种求调强放疗中最佳笔射束强度分布的改进方法[J].北京生物医学工程,1999,(3):166.
[20] Rasch C, Keus R, Pameijer FA, et al. The potential impact of CT-MRI matching on tumor volume delineation in advanced head and neck cancer[J]. Int J Radiat Oncol Biol Phys, 1997, 39(4):841-848.
[21] Emami B, Sethi A, Petruzzelli GJ. Influence of MRI on target volume delineation and IMRT planning in nasopharyngeal carcinoma[J]. Int J Radiat Oncol Biol Phys, 2003, 57(2):481-488.
[22] Nishioka T, Shiga T, Shirato H, et al. Image fusion between 18FDG-PET and MRI/CT for radiotherapy planning of oropharyngeal and nasopharyngeal carcinomas[J]. Int J Radiat Oncol Biol Phys, 2002, 53(4):1051-1057.
[23]陈波,易俊林,高黎,等.鼻咽癌IMRT靶区勾画与计划制定期间肿瘤体积的变化.中华放射肿瘤学杂志,2007,16(3):161-167.
[24]曹建忠,罗京伟,徐国镇,等.鼻咽癌调强放疗中靶区和正常器官变化规律及临床意义探讨.中华放射肿瘤学杂志,2007,16(2):81-85.
[25]郭明芳,郭雷鸣,赵娅琴,等.锥形束CT研究肺癌放射治疗中的摆位误差.中国肿瘤临床,2009,36(15):848-852.
[26] Dai JR,Hu YM;Implement of Image Guided Radiation Therapy. Chin J Radiat Oncol,2006,Vol 15,132-135.
[27] Downs,T.M.;Roach,M.;Gmssfeld,G.D.;et al.The University of California,San Francisco(UCSF)experience with permanently implanted gold markers for dailyprostate realignment during radiation therapy[J].Int. Radiat.Onco1.Bio1.Phys, 2002,54:80.