图像引导下宫颈癌容积旋转调强放疗中膀胱和直肠实际受照剂量评估
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摘要
目的:研究宫颈癌容积旋转调强放疗过程中,利用图像引导技术评估膀胱与直肠因平移摆位误差因素对受照剂量的影响。方法:入组2017年2～4月的25例行容积旋转调强放疗的宫颈癌病人。在计划CT图像和首次摆位的锥形束CT(CBCT)图像中勾画出膀胱和直肠。然后根据首次摆位误差,对膀胱和直肠在前后、左右、头脚方向上进行相应的平移。分别比较计划设计与加入平移摆位误差下的膀胱和直肠剂量差异,并用配对t检验分析差异。结果:在计划CT与CBCT图像上勾画出的直肠体积为(33.0±16.0)和(21.8±16.5)cm3,膀胱体积为(387.1±222.3)和(227.8±107.3)cm3。在计划CT图像与考虑平移摆位误差的CBCT图像上,直肠的V50为(17.27±13.42)%和(23.9±26.58)%,膀胱的V50为(33.59±12.2)%和(44.27±22.61)%,直肠的最大剂量为(5 324±383)和(5 370±441)c Gy,膀胱的最大剂量为(5 547±365)和(5 513±328)c Gy。直肠和膀胱的V50均有统计学意义(t=-3.60, P<0.01;t=-2.98, P<0.01),直肠和膀胱的最大剂量均无统计学意义(t=-1.18, P=0.20;t=0.66, P=0.51)。结论:宫颈癌放射治疗中,膀胱和直肠在计划CT和首次治疗时的体积与剂量均有较大差异,故应该多次采集图像来评估剂量分布,才能准确评价放射治疗的真正疗效。
Objective To evaluate the effects of translational setup errors on the doses to bladder and rectum during imageguided volumetric modulated arc therapy for cervical cancer. Methods Twenty-five patients receiving volumetric modulated arc therapy for cervical cancer from February 2017 to April 2017 were enrolled in this study. Bladder and rectum were delineated on the planning computed tomography(CT) images and the cone beam CT(CBCT) images obtained in the first treatment fraction. Then, bladder and rectum were shifted in the anterior-posterior, left-right, and superior-inferior directions according to the first setup errors. The planned dose of bladder and rectum were compared by those data obtained with CBCT images considering setup errors, and the dosimetric differences were compared with paired t-test. Results The rectum volumes delineated on the planning CT and CBCT images were(33.0±16.0) cm3 and(21.8±16.5) cm3, respectively,and the bladder volumes were(387.1±222.3) and(227.8±107.3) cm3, respectively. The V50 of rectum based on the planning CT and CBCT images was(17.27±13.42) % and(23.9±26.58) %, respectively; and the V50 of bladder was(33.59±12.2) %and(44.27±22.61) %, respectively, with statistical differences(t=-3.60, P<0.01; t=-2.98,P<0.01). The maximum dose of rectum based on the planning CT and CBCT images was(5 324±383) and(5 370±441) cGy, respectively; and the maximum dose of bladder was(5 547±365) and(5 513±328) cGy, respectively, with no statistical differences(t=-1.18, P=0.20; t=0.66,P=0.51). Conclusion During the radiotherapy course for cervical cancer, the volumes and doses of bladder and rectum in planning CT are significantly different from those in the first treatment fraction. CT images should be obtained for multiple fractions to evaluate the dose distribution and further assess the benefits of radiotherapy.
Objective To evaluate the effects of translational setup errors on the doses to bladder and rectum during imageguided volumetric modulated arc therapy for cervical cancer. Methods Twenty-five patients receiving volumetric modulated arc therapy for cervical cancer from February 2017 to April 2017 were enrolled in this study. Bladder and rectum were delineated on the planning computed tomography(CT) images and the cone beam CT(CBCT) images obtained in the first treatment fraction. Then, bladder and rectum were shifted in the anterior-posterior, left-right, and superior-inferior directions according to the first setup errors. The planned dose of bladder and rectum were compared by those data obtained with CBCT images considering setup errors, and the dosimetric differences were compared with paired t-test. Results The rectum volumes delineated on the planning CT and CBCT images were(33.0±16.0) cm3 and(21.8±16.5) cm3, respectively,and the bladder volumes were(387.1±222.3) and(227.8±107.3) cm3, respectively. The V50 of rectum based on the planning CT and CBCT images was(17.27±13.42) % and(23.9±26.58) %, respectively; and the V50 of bladder was(33.59±12.2) %and(44.27±22.61) %, respectively, with statistical differences(t=-3.60, P<0.01; t=-2.98,P<0.01). The maximum dose of rectum based on the planning CT and CBCT images was(5 324±383) and(5 370±441) cGy, respectively; and the maximum dose of bladder was(5 547±365) and(5 513±328) cGy, respectively, with no statistical differences(t=-1.18, P=0.20; t=0.66,P=0.51). Conclusion During the radiotherapy course for cervical cancer, the volumes and doses of bladder and rectum in planning CT are significantly different from those in the first treatment fraction. CT images should be obtained for multiple fractions to evaluate the dose distribution and further assess the benefits of radiotherapy.
引文
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[10]ZHU J, BAI T, GU J, et al. Effects of megavoltage computedtomographic scan methodology on setup verification and adaptivedose calculation in helical Tomo Therapy[J]. Radiat Oncol, 2018, 13:80.
[11]TAYLOR A, POWELL M E. An assessment of interfractional uterineand cervical motion:implications for radiotherapy target volumedefinition in gynecological cancer[J]. Radiother Oncol, 2008, 88:250-257.
[12]OH Y, BAEK J, KIM O, et al. Assessment of setup uncertainties forvarious tumor sites when using daily CBCT for more than 2200 VMATtreatments[J]. J Appl Clin Med Phys, 2014, 15(2):85-99.
[13]YAO L, ZHU L, WANG J, et al. Positioning accuracy during VMATof gynecologic malignancies and the resulting dosimetric impact bya 6-degree-of-freedom couch in combination with daily kilovoltagecone beam computed tomography[J]. Radiat Oncol, 2015, 10:104.
[14]JI S, HU Q, ZHU J, et al. Combined pretreatment with18F-FDG PET/CT and comet assay guides the concurrent chemoradiotherapy oflocally advanced cervical cancer:study protocol for a randomizedcontrolled trial[J]. Trials, 2018, 19(1):416.
[15]YIN Y J, LI H Q, SHENG X G, et al. The treatment of pelviclocoregional recurrence of cervical cancer after radical surgery withintensity-modulated radiation therapy compared with conventionalradiotherapy:a retrospective study[J]. Int J Gynecol Cancer, 2015, 25(6):1058-1065.
[16]KWAK Y K, LEE S W, KAY C S, et al. Intensity-modulatedradiotherapy reduces gastrointestinal toxicity in pelvic radiationtherapy with moderate dose[J]. PLoS One, 2017, 12(8):e0183339.
[17]林原,周莉均,徐志勇,等.宫颈癌术后盆腔三维适形与调强放疗剂量学与技术的研究[J].中华放射肿瘤学杂志, 2008, 17(5):372-376.LIN Y, ZHOU L J, XU Z Y, et al. Technical and dosimetric study ofthree-dimensional conformal and intensity-modulated pelvicradiothrapy for post-hysterectonmy cervical carcinoma[J]. ChineseJournal of Radiation Oncology, 2008, 17(5):372-376.
[18]YUE N J, KNISELY J P, SONG H, et al. A method to implement fullsix-degree target shift corrections for rigid body in image-guidedradiotherapy[J]. Med Phys, 2006, 33(1):21-31.
[19]KAISER A, SCHULTHEISS T E, WONG J Y, et al. Pitch, roll, andyaw variations in patient positioning[J]. Int J Radiat Oncol Biol Phys,2006, 66(3):949-955.
[2] LEE T F, TING H M, CHAO P J, et al. Dual arc volumetric-modulatedarc radiotherapy(VMAT)of nasopharyngeal carcinomas:asimultaneous integrated boost treatment plan comparison withintensity-modulated radiotherapies and single arc VMAT[J]. ClinOncol, 2012, 24(3):196-207.
[3] POPESCU C C, OLIVOTTO I A, BECKHAM W A, et al. Volumetricmodulated arc therapy improves dosimetry and reduces treatment timecompared to conventional intensity-modulated radiotherapy forlocoregional radiotherapy of left-sided breast cancer and internalmammary nodes[J]. Int J Radiat Oncol Biol Phys, 2010, 76(1):287-295.
[4] RAO M, YANG W, CHEN F, et al. Comparison of Elekta VMAT withhelical tomotherapy and fixed field IMRT:plan quality, deliveryefficiency and accuracy[J]. Med Phys, 2010, 37(3):1350-1359.
[5] GUO M, HUANG E, LIU X, et al. Volumetric modulated arc therapyversus fixed-field intensity-modulated radiotherapy in radicalirradiation for cervical cancer without lymphadenectasis:dosimetricand clinical results[J]. Oncol Res Treat, 2018, 41(3):105-109.
[6] DU X L, TAO J, SHENG X G, et al. Intensity-modulated radiationtherapy for local advanced cervical cancer:a comparison of dosimetricand clinical outcomes with conventional radiotherapy[J]. GynecolOncol, 2012, 125(1):151-157.
[7] HERRERA F G, CALLAWAY S, DELIKGOZ-SOYKUT E, et al.Retrospective feasibility study of simultaneous integrated boost incervical cancer using tomotherapy:the imapct of organ motion andtumor regression[J]. Radiat Oncol, 2013, 8(5):1-10.
[8] JADON R, PEMBROKE C A, HANNA C L, et al. A systematic reviewof organ motion and image-guided strategies in external beamradiotherapy for cervical cancer[J]. Clin Oncol, 2014, 26(4):185-196.
[9] GEORG D, KIRISTS C, HILLBRAND M, et al. Image-guidedradiotherapy for cervix cancer:high-tech external beam therapy versushigh-tech brachytherapy[J]. Int J Radiat Oncol Biol Phys, 2008, 71(4):1272-1278.
[10]ZHU J, BAI T, GU J, et al. Effects of megavoltage computedtomographic scan methodology on setup verification and adaptivedose calculation in helical Tomo Therapy[J]. Radiat Oncol, 2018, 13:80.
[11]TAYLOR A, POWELL M E. An assessment of interfractional uterineand cervical motion:implications for radiotherapy target volumedefinition in gynecological cancer[J]. Radiother Oncol, 2008, 88:250-257.
[12]OH Y, BAEK J, KIM O, et al. Assessment of setup uncertainties forvarious tumor sites when using daily CBCT for more than 2200 VMATtreatments[J]. J Appl Clin Med Phys, 2014, 15(2):85-99.
[13]YAO L, ZHU L, WANG J, et al. Positioning accuracy during VMATof gynecologic malignancies and the resulting dosimetric impact bya 6-degree-of-freedom couch in combination with daily kilovoltagecone beam computed tomography[J]. Radiat Oncol, 2015, 10:104.
[14]JI S, HU Q, ZHU J, et al. Combined pretreatment with18F-FDG PET/CT and comet assay guides the concurrent chemoradiotherapy oflocally advanced cervical cancer:study protocol for a randomizedcontrolled trial[J]. Trials, 2018, 19(1):416.
[15]YIN Y J, LI H Q, SHENG X G, et al. The treatment of pelviclocoregional recurrence of cervical cancer after radical surgery withintensity-modulated radiation therapy compared with conventionalradiotherapy:a retrospective study[J]. Int J Gynecol Cancer, 2015, 25(6):1058-1065.
[16]KWAK Y K, LEE S W, KAY C S, et al. Intensity-modulatedradiotherapy reduces gastrointestinal toxicity in pelvic radiationtherapy with moderate dose[J]. PLoS One, 2017, 12(8):e0183339.
[17]林原,周莉均,徐志勇,等.宫颈癌术后盆腔三维适形与调强放疗剂量学与技术的研究[J].中华放射肿瘤学杂志, 2008, 17(5):372-376.LIN Y, ZHOU L J, XU Z Y, et al. Technical and dosimetric study ofthree-dimensional conformal and intensity-modulated pelvicradiothrapy for post-hysterectonmy cervical carcinoma[J]. ChineseJournal of Radiation Oncology, 2008, 17(5):372-376.
[18]YUE N J, KNISELY J P, SONG H, et al. A method to implement fullsix-degree target shift corrections for rigid body in image-guidedradiotherapy[J]. Med Phys, 2006, 33(1):21-31.
[19]KAISER A, SCHULTHEISS T E, WONG J Y, et al. Pitch, roll, andyaw variations in patient positioning[J]. Int J Radiat Oncol Biol Phys,2006, 66(3):949-955.