CBCT在线校准技术对宫颈癌术后调强放射治疗外放边界影响及剂量学差异分析
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摘要
通过锥形束计算机断层扫描(Cone beam computed tomography,CBCT)在线校准与非在线校准所得误差数据,推导出两个不同的计划靶区(Planning target volume,PTV)外放边界,分别设计计划,分析不同外放边界对靶区及危及器官的剂量学差异。推导计算可知,未行CBCT在线校准PTV的外放边界X、Y、Z方向分别为5.50、9.89、5.83 mm,行CBCT在线校准PTV的外放边界X、Y、Z方向分别为3.73、5.16、4.36 mm;两种不同外放所得膀胱及直肠的V_(30)、V_(40)、V_(50)、D_(mean),小肠的V_(20)、V_(30)、V_(40)、V_(50)、D_(mean),盆骨髓的V_(10)、V_(20)、V_(30)、V_(40)、V_(50)、D_(mean),左右股骨头的V_(50)、D_(mean)均有显著的统计学差异(p<0.05);临床靶区(Clinical target volume,CTV)的D_2、D_5、D_(50)、D_(mean)及均匀性指数(I_H)、适形度指数(I_C)均有显著的统计学差异(p<0.05);行CBCT在线校准若PTV外放过大,危及器官的受量将明显偏高,未行CBCT在线校准若PTV外放过小,靶区受量将明显欠量。使用CBCT在线校准技术可以大幅度减小摆位误差,提高摆位精度,同时PTV外放边界应需和行CBCT在线校准与否密切联动,以避免靶区欠量及危及器官受量偏高的现象,保证治疗质量。
Two designs of planning target volume(PTV)of target margins were derived from the setup errors with or without cone-beam computed tomography(CBCT)online alignment.Different plans were designed with these two sets of PTV target margins using treatment planning systems(TPS).We analyzed dosimetric differences in the target and organ at risk(OAR)caused by different designs of PTV target margins.The two designs of PTV target margins in the X,Y and Z directions,respectively,were as follows:3.73,5.16 and 4.36 mm and 5.5,9.89 and 5.83 mm;these designs were derived from setup errors with or without CBCT online alignment.Significant statistical differences(p<0.05)were found among V_(30),V_(40),V_(50) and D_(mean )of the bladder and rectum;V_(20),V_(30),V_(40),V_(50) and D_(mean) of tne small intestine;V_(10),V_(20),V_(30),V_(40),V_(50) and D_(mean )of the marrow;and V_(50) and D_(mean) of the left and right femoral head.Significant statistical differences(p<0.05)were also found in D_2,D_5,D_(50) and D_(mean) of clinical target volume(CTV),homogeneity index(I_H)and conformity index(I_C).The dose in the OAR will on the high side if using larger target margin of PTV with CBCT online alignment,and the dose deficiency was significant in the target if using smaller target margin of PTV without CBCT online alignment.CBCT online alignment can reduce the setup errors and improve the accuracy of the patient positioning.The choice of PTV target margin should be related with the choice of CBCT online alignment,so as to avoid dose deficiency in the target and excessive radiation in the OAR to improve the radiotherapy quality.
Two designs of planning target volume(PTV)of target margins were derived from the setup errors with or without cone-beam computed tomography(CBCT)online alignment.Different plans were designed with these two sets of PTV target margins using treatment planning systems(TPS).We analyzed dosimetric differences in the target and organ at risk(OAR)caused by different designs of PTV target margins.The two designs of PTV target margins in the X,Y and Z directions,respectively,were as follows:3.73,5.16 and 4.36 mm and 5.5,9.89 and 5.83 mm;these designs were derived from setup errors with or without CBCT online alignment.Significant statistical differences(p<0.05)were found among V_(30),V_(40),V_(50) and D_(mean )of the bladder and rectum;V_(20),V_(30),V_(40),V_(50) and D_(mean) of tne small intestine;V_(10),V_(20),V_(30),V_(40),V_(50) and D_(mean )of the marrow;and V_(50) and D_(mean) of the left and right femoral head.Significant statistical differences(p<0.05)were also found in D_2,D_5,D_(50) and D_(mean) of clinical target volume(CTV),homogeneity index(I_H)and conformity index(I_C).The dose in the OAR will on the high side if using larger target margin of PTV with CBCT online alignment,and the dose deficiency was significant in the target if using smaller target margin of PTV without CBCT online alignment.CBCT online alignment can reduce the setup errors and improve the accuracy of the patient positioning.The choice of PTV target margin should be related with the choice of CBCT online alignment,so as to avoid dose deficiency in the target and excessive radiation in the OAR to improve the radiotherapy quality.
引文
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15 Siebers J V,Keall P J,Wu Q,et al.Effect of patient set-up errors onsimultaneously integrated boost head and neck IMRT treatment plans[J].International Journal of Radiation Oncology Biology Physics,2005,63(2):422-433.DOI:10.1016/j.ijrobp.2005.02.029.
16 Engelsman M,Sharp G C,Bortfied T,et al.How much marign reduction is possible through gating or breath hold[J].Physics in Medicin and Biology,2011,50(3):477-490.DOI:10.1088/0031-9155/50/3/006.
17尚凯,迟子峰,王军,等.胸段食管癌IGRT中摆位误差分析[J].中华放射肿瘤学杂志,2015,24(1):70-73.DOI:10.3760/cma.j.issn.1004-4221.2015.01.019.SHANG Kai,CHI Zifeng,WANG Jun,et al.The analysis of set-up error inimage-guided radiotherapy with thoracic esophageal carcinoma[J].Chinese Journal of Radiation Oncology,2015,24(1):70-73.DOI:10.3760/cma.j.issn.1004-4221.2015.01.019.
18刘利彬,吴君心,瞿宜艳,等.应用CBCT研究胸腹部肿瘤IMRT两种体位固定技术的摆位误差[J].中华放射肿瘤学杂志,2014,23(1):48-51.DOI:10.3760/cma.j.issn.1004-4221.2014.01.013.LIU Libin,WU Junxin,QU Yiyan,et al.Study the setup errors by CBCT in radiotherapy with two different immobilization techniques for thoracic and abdominal tumors[J].Chinese Journal of Radiation Oncology,2014,23(1):48-51.DOI:10.3760/cma.j.issn.1004-4221.2014.01.013.
19 Schiffner D C,Schultheiss T E,Chen Y J,et al.Can less-than-daily image guided radiation therapy(IGRT)be used to treat esophageal cancer?A study of patient positioning errors and their dosimetric consequences[J].International Journal of Radiation Oncology Biology Physics,2008,72(1):S537-S538.DOI:10.1016/j.ijrobp.2008.06.078.
20 Christodoulou M,Bayman N,Mccloskey P,et al.New radiotherapy approaches in locally advanced non-small cell lung cancer[J].European Journal of Cancer,2014,50(3):525-534.DOI:10.1016/j.ejca.2013.11.027.
21 Chang J Y,Bezjak A,Mornex F.Stereotactic ablativeradiotherapy for centrally located early stage nonsmall-cell lungcancer:what we have learned[J].Journal of Thoracic Oncology,2015,10(4):577-585.DOI:10.1097/JTO.0000000000000453.
22 Kong F M,Zhao J,Wang J,et al.Radiation dose effect inlocally advanced non-small cell lung cancer[J].Journal of Thoracic Disease,2014,6(4):336-347.DOI:10.3978/j.issn.2072-1439.2014.01.23.
2 Mackie T R,Kapatoes J,Ruchala K,et al.Image guidance for perciseconformal radiotherapy[J].International Journal of Radiation Oncology Biology Physics,2003,56(1):89-105.DOI:org/10.1016/S0360-3016(03)00090-7.
3 Havrilesky L J,Kulasingam S L,Matchar D B,et al.FDG-PET formanagement of cervical and ovarian cancer[J].Gynecol Oncol,2005,97(1):183-191.DOI:10.1016/j.ygyno.2004.12.007.
4 Feuvret L,No?l G,Mazeron J J,et al.Conformity index:a review[J].International Journal of Radiation Oncology Biology Physics,2006,64(2):333-342.DOI:10.1016/j.ijrobp.2005.09.028.
5 Hodapp N.The ICRU Report 83:prescribing,recording and reporting photon-beam intensity-modulated radiation therapy(IMRT)[J].Strahlentherapie Und Onkologie,2012,188(1):97-99.DOI:10.1007/s00066-011-0015-x.
6 Stroom J C,Heijmen B J.Geometrical uncertainties,radiotherapy planning margins,and the ICRU-62 report[J].Radiotherapy and Oncology,2002,64(1):75-83.DOI:10.1016/S0167-8140(02)00140-8.
7 Remeijer P,Geerlof E,Ploeger L,et al.3-D portal image analysis in clinical practice:an evalution of 2-D and3-Danalysis techniques as applied to 30 prostate cancer patients[J].International Journal of Radiation Oncology Biology Physics,2000,46(5):1281-1290.DOI:10.1016/S0360-3016(99)00468-X.
8 Stroom J C,de Boer H C,Huizenga H,et al.Inclusion of geometrical uncertainties in radiotherapy treatment planning by means of coverage probalibility[J].International Journal of Radiation Oncology Biology Physics,1999,43(6):905-915.DOI:10.1016/S0360-3016(98)00468-4.
9 Stroom J C,Koper P C,Korevaar G A,et al.Internal organ motion in prostate cancer patients treated in prone and supine treatment position[J].Radiotherapy&Oncology Journal of the European Society for Therapeutic Radiology&Oncology,1999,51(3):237-248.DOI:10.1016/S0167-8140(99)00061-4.
10 Van H M,Remeijer P,Lebesque J V.Inclusion of geometric uncertainties in treatment plan evaluation[J].International Journal of Radiation Oncology Biology Physics,2002,52(5):1407-1422.DOI:10.1016/S0360-3016(01)02805-X.
11 Van H M.Errors and margins in radiotherapy[J].Seminars in Radiation Oncology,2004,14(1):52-64.DOI:10.1053/j.semradonc.2003.10.003.
12 Van H M,Remeijer P,Rasch C.The probability of corret target dosage:dose-population histograms for deriving treatment margins in radiotherapy[J].International Journal of Radiation Oncology Biology Physics,2000,47(4):1121-1135.DOI:10.1016/S0360-3016(00)00518-6.
13 Hurkmans C W,Remeijer P,Lebesque J V,et al.Set-up verification using portal imaging:Review of current clinical practice[J].Radiotherapy and Oncology,2001,58(2):105-120.DOI:10.1016/S0167-8140(00)00260-7.
14 Rietzel E,Pan T,Chen G T.Four-dimensional computed tomography:Image formation and clinical protocol[J].Medical Physics,2005,32(4):874-889.DOI:10.1118/1.1869852.
15 Siebers J V,Keall P J,Wu Q,et al.Effect of patient set-up errors onsimultaneously integrated boost head and neck IMRT treatment plans[J].International Journal of Radiation Oncology Biology Physics,2005,63(2):422-433.DOI:10.1016/j.ijrobp.2005.02.029.
16 Engelsman M,Sharp G C,Bortfied T,et al.How much marign reduction is possible through gating or breath hold[J].Physics in Medicin and Biology,2011,50(3):477-490.DOI:10.1088/0031-9155/50/3/006.
17尚凯,迟子峰,王军,等.胸段食管癌IGRT中摆位误差分析[J].中华放射肿瘤学杂志,2015,24(1):70-73.DOI:10.3760/cma.j.issn.1004-4221.2015.01.019.SHANG Kai,CHI Zifeng,WANG Jun,et al.The analysis of set-up error inimage-guided radiotherapy with thoracic esophageal carcinoma[J].Chinese Journal of Radiation Oncology,2015,24(1):70-73.DOI:10.3760/cma.j.issn.1004-4221.2015.01.019.
18刘利彬,吴君心,瞿宜艳,等.应用CBCT研究胸腹部肿瘤IMRT两种体位固定技术的摆位误差[J].中华放射肿瘤学杂志,2014,23(1):48-51.DOI:10.3760/cma.j.issn.1004-4221.2014.01.013.LIU Libin,WU Junxin,QU Yiyan,et al.Study the setup errors by CBCT in radiotherapy with two different immobilization techniques for thoracic and abdominal tumors[J].Chinese Journal of Radiation Oncology,2014,23(1):48-51.DOI:10.3760/cma.j.issn.1004-4221.2014.01.013.
19 Schiffner D C,Schultheiss T E,Chen Y J,et al.Can less-than-daily image guided radiation therapy(IGRT)be used to treat esophageal cancer?A study of patient positioning errors and their dosimetric consequences[J].International Journal of Radiation Oncology Biology Physics,2008,72(1):S537-S538.DOI:10.1016/j.ijrobp.2008.06.078.
20 Christodoulou M,Bayman N,Mccloskey P,et al.New radiotherapy approaches in locally advanced non-small cell lung cancer[J].European Journal of Cancer,2014,50(3):525-534.DOI:10.1016/j.ejca.2013.11.027.
21 Chang J Y,Bezjak A,Mornex F.Stereotactic ablativeradiotherapy for centrally located early stage nonsmall-cell lungcancer:what we have learned[J].Journal of Thoracic Oncology,2015,10(4):577-585.DOI:10.1097/JTO.0000000000000453.
22 Kong F M,Zhao J,Wang J,et al.Radiation dose effect inlocally advanced non-small cell lung cancer[J].Journal of Thoracic Disease,2014,6(4):336-347.DOI:10.3978/j.issn.2072-1439.2014.01.23.