静态调强放疗等中心点对鼻咽癌剂量学的影响
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摘要
目的:分析调强放射治疗等中心点的选择对鼻咽癌剂量学的影响,为治疗计划的设计提供参考依据。方法:选取17例鼻咽癌病例,分别以原发肿瘤和咽后淋巴结临床治疗靶区PGTVnx的中心点(以AP表示)和预防照射区临床治疗靶区PTV的中心点(以BP表示)作为治疗计划的等中心点,设计调强放疗计划。比较靶区的适形度指数以及均匀性指数、危及器官的最高剂量以及正常组织的低剂量体积。结果:两种治疗计划均能满足临床剂量要求。在所有靶区剂量体积百分比没有明显统计学差异情况下,AP组和BP组的靶区的适形度指数以及均匀性指数差异无统计学意义。但是AP组的视交叉_(D0.03 cm~3)剂量要明显低于BP组,分别为(36.7±12.1)Gy和(38.8±11.2)Gy(t=-3.070, P<0.01);AP组的正常组织V<30 Gy明显大于BP组,分别为(8 250±1 686)cm3和(8 166±1 669)cm~3(t=3.799, P<0.01)。结论:AP能明显降低视交叉的最高剂量,并且能降低正常组织的高剂量体积,减少病人的正常组织放疗并发症概率。
Objective To analyze the dosimetric effects of different isocenters on intensity-modulated radiotherapy(IMRT) for nasopharyngeal carcinoma(NPC) for providing reference for the design of treatment plan. Methods Seventeen patients with NPC were enrolled in this study. Two different kinds of IMRT plans were designed with different isocenters, namely one with the center of the primary tumor and pharyngeal lymph nodes clinical target area PGTVnx(AP) and the other with the center of prophylactic irradiation area clinical target area PTV(BP). The conformity index and homogeneity index of target areas, the maximum dose of organs-at-risk, and the low dose volume of normal tissues were compared between two different plans. Results Both two different kinds of IMRT plans met clinic dosimetric requirements. In the case of no statistical differences were found in the dose volume percentage of target areas, the homogeneity index and conformity index of target areas were similar in AP group and BP group, but compared with BP group, AP group had lower D_(0.03 cm~3) of the optic chiasm [(36.7±12.1) Gy vs(38.8±11.2) Gy; t=-3.070,P<0.01] and higher V<30 Gyof normal tissues [(8 250±1 686) cm~3 vs(8 166±1 669) cm~3; t=3.799, P<0.01]. Conclusion AP can significantly decrease the maximum dose of optic chiasm and the high dose volume of normal tissues, so as to lower the normal tissue complication probability.
Objective To analyze the dosimetric effects of different isocenters on intensity-modulated radiotherapy(IMRT) for nasopharyngeal carcinoma(NPC) for providing reference for the design of treatment plan. Methods Seventeen patients with NPC were enrolled in this study. Two different kinds of IMRT plans were designed with different isocenters, namely one with the center of the primary tumor and pharyngeal lymph nodes clinical target area PGTVnx(AP) and the other with the center of prophylactic irradiation area clinical target area PTV(BP). The conformity index and homogeneity index of target areas, the maximum dose of organs-at-risk, and the low dose volume of normal tissues were compared between two different plans. Results Both two different kinds of IMRT plans met clinic dosimetric requirements. In the case of no statistical differences were found in the dose volume percentage of target areas, the homogeneity index and conformity index of target areas were similar in AP group and BP group, but compared with BP group, AP group had lower D_(0.03 cm~3) of the optic chiasm [(36.7±12.1) Gy vs(38.8±11.2) Gy; t=-3.070,P<0.01] and higher V<30 Gyof normal tissues [(8 250±1 686) cm~3 vs(8 166±1 669) cm~3; t=3.799, P<0.01]. Conclusion AP can significantly decrease the maximum dose of optic chiasm and the high dose volume of normal tissues, so as to lower the normal tissue complication probability.
引文
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[5]张烨,黄晓东,高黎,等.鼻咽癌IMRT后长期存活者晚期损伤及其变化趋势-患者评价和医生评价结果[J].中华放射肿瘤学杂志, 2018,27(8):721-726.ZHANG Y, HUANG X D, GAO L, et al. The change trend of late complications in patients with nasopharyngeal carcinoma treated by intensity-modulated radiotherapy:the clinician-and patient-reported outcomes[J]. Chinese Journal of Radiation Oncology, 2018, 27(8):721-726.
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[10]WU Q J, LI T, YUAN L, et al. Single institution's dosimetry and IGRT analysis of prostate SBRT[J]. Radiat Oncol, 2013, 8(1):215.
[11]LEE T F, FANG F M, CHAO P J, et al. Dosimetric comparisons of helical tomotherapy and step-and-shoot intensity-modulated radiotherapy in nasopharyngeal carcinoma[J]. Radiat Oncol, 2008, 89(1):89-96.
[12]LEE T F, CHAO P J, TING H M, et al. Comparative analysis of SmartArc-based dual arc volumetric-modulated arc radiotherapy(VMAT)versus intensity-modulated radiotherapy(IMRT)for nasopharyngeal carcinoma[J]. J Appl Clin Med Phys, 2011, 12(4):3591-3592.
[13]WANG J Q, CHEN Z, LI W W, et al. A new strategy for volumetricmodulated arc therapy planning using AutoPlanning based multicriteria optimization for nasopharyngeal carcinoma[J]. Radiat Oncol, 2018, 13:94-104.
[14]LU S H, CHENG J C, KUO S H, et al. Volumetric modulated arc therapy for nasopharyngeal carcinoma:a dosimetric comparison with Tomo Therapy and step-and-shoot IMRT[J]. Radiother Oncol, 2012,104(3):324-330.
[15]SHENG K, MOLLOY J A, READ P W. Intensity-modulated radiation therapy(IMRT)dosimetry of the head and neck:a comparison of treatment plans using linear accelerator-based IMRT and helical tomotherapy[J]. Int J Radiat Oncol Biol Phys, 2006, 65(3):917-923.
[16]CHO Y B, LAPERRIERE N, HODAIE M, et al. Hybrid isocenter technique for Gamma-Knife Perfexion treatment of trigeminal neuralgia[J]. Med Dosim, 2016, 41(4):271-276.
[17]RUGGIERI R, NACCARATO S, MAZZOLA R, et al. Linac-based VMAT radiosurgery for multiple brain lesions:comparison between a conventional multi-isocenter approach and a new dedicated monoisocenter technique[J]. Radiat Oncol, 2018, 13(1):38.
[18]BOMAN E, ROSSI M, KAPANEN M. The robustness of dual isocenter VMAT radiation therapy for bilateral lymph node positive breast cancer[J]. Phys Med, 2017, 44:11-17.
[19]JIN X C, WU S X, YU J Y, et al. Technical and dosimetric considerations in multi-isocenter intensity modulated radiotherapy for nasopharyngeal carcinoma with small multileaf collimator[J]. Med Dosim, 2009, 34(1):9-15.
[20]易俊林,高黎,徐国镇,等. 147例鼻咽癌调强放疗结果分析[J].中华放射肿瘤学杂志, 2008, 17(5):329-334.YI J L, GAO L, XU G Z, et al. Treatment results of intensity modulated radiotherapy for nasopharyngeal carcinoma:an analysis of 147 patients[J]. Chinese Journal of Radiation Oncology, 2008,17(5):329-334.
[2] FERLAY J, SOERJOMATARAM I, DIKSHIT R, et al. Cancer incidence and mortality worldwide:sources, methods and major patterns in GLOBOCAN 2012[J]. Int J Cancer, 2015, 136(5):E359-E386.
[3] YU M C, YUAN J M. Epidemiology of nasopharyngeal carcinoma[J].Semin Cancer Biol, 2002, 12(6):421-429.
[4] WU L R, LIU Y T, JIANG N, et al. Ten-year survival outcomes for patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy:an analysis of 614 patients from a single center[J]. Oral Oncol, 2017, 69:26-32.
[5]张烨,黄晓东,高黎,等.鼻咽癌IMRT后长期存活者晚期损伤及其变化趋势-患者评价和医生评价结果[J].中华放射肿瘤学杂志, 2018,27(8):721-726.ZHANG Y, HUANG X D, GAO L, et al. The change trend of late complications in patients with nasopharyngeal carcinoma treated by intensity-modulated radiotherapy:the clinician-and patient-reported outcomes[J]. Chinese Journal of Radiation Oncology, 2018, 27(8):721-726.
[6]刘志萍,田源,王洪智,等.鼻咽癌IMRT中气腔对靶区及OAR剂量影响[J].中华放射肿瘤学杂志, 2017, 26(8):862-866.LIU Z P, TIAN Y, WANG H Z, et al. Dosimetric effects of air cavity on target volume and organs at risk during intensity-modulated radiation therapy for nasopharyngeal carcinoma[J]. Chinese Journal of Radiation Oncology, 2017, 26(8):862-866.
[7] LEE T F, TING H M, CHAO P J, et al. Dual arc volumetric-modulated radiotherapy(VMAT)of nasopharyngeal carcinomas:a simultaneous integrated boost treatment plan comparison with intensity-modulated radiotherapies and single arc VMAT[J]. Clin Oncol, 2011, 24(3):196-207.
[8]蒋璐,邱小平,单国平,等.鼻咽癌放疗中摆位误差及解剖结构变化对剂量学的影响[J].中国医学物理学杂志, 2017, 34(4):348-354.JIANG L, QIU X P, SHAN G P, et al. Influence of anatomical changes and setup error on radiotherapy dosimetry in patients with nasopharyngeal carcinoma[J]. Chinese Journal of Medical Physics,2017, 34(4):348-354.
[9] EMAMI B, LYMAN J, BROWN A, et al. Tolerance of normal tissue to therapeutic irradiation[J]. Int J Radiat Oncol Biol Phys, 1991, 21(1):109-122.
[10]WU Q J, LI T, YUAN L, et al. Single institution's dosimetry and IGRT analysis of prostate SBRT[J]. Radiat Oncol, 2013, 8(1):215.
[11]LEE T F, FANG F M, CHAO P J, et al. Dosimetric comparisons of helical tomotherapy and step-and-shoot intensity-modulated radiotherapy in nasopharyngeal carcinoma[J]. Radiat Oncol, 2008, 89(1):89-96.
[12]LEE T F, CHAO P J, TING H M, et al. Comparative analysis of SmartArc-based dual arc volumetric-modulated arc radiotherapy(VMAT)versus intensity-modulated radiotherapy(IMRT)for nasopharyngeal carcinoma[J]. J Appl Clin Med Phys, 2011, 12(4):3591-3592.
[13]WANG J Q, CHEN Z, LI W W, et al. A new strategy for volumetricmodulated arc therapy planning using AutoPlanning based multicriteria optimization for nasopharyngeal carcinoma[J]. Radiat Oncol, 2018, 13:94-104.
[14]LU S H, CHENG J C, KUO S H, et al. Volumetric modulated arc therapy for nasopharyngeal carcinoma:a dosimetric comparison with Tomo Therapy and step-and-shoot IMRT[J]. Radiother Oncol, 2012,104(3):324-330.
[15]SHENG K, MOLLOY J A, READ P W. Intensity-modulated radiation therapy(IMRT)dosimetry of the head and neck:a comparison of treatment plans using linear accelerator-based IMRT and helical tomotherapy[J]. Int J Radiat Oncol Biol Phys, 2006, 65(3):917-923.
[16]CHO Y B, LAPERRIERE N, HODAIE M, et al. Hybrid isocenter technique for Gamma-Knife Perfexion treatment of trigeminal neuralgia[J]. Med Dosim, 2016, 41(4):271-276.
[17]RUGGIERI R, NACCARATO S, MAZZOLA R, et al. Linac-based VMAT radiosurgery for multiple brain lesions:comparison between a conventional multi-isocenter approach and a new dedicated monoisocenter technique[J]. Radiat Oncol, 2018, 13(1):38.
[18]BOMAN E, ROSSI M, KAPANEN M. The robustness of dual isocenter VMAT radiation therapy for bilateral lymph node positive breast cancer[J]. Phys Med, 2017, 44:11-17.
[19]JIN X C, WU S X, YU J Y, et al. Technical and dosimetric considerations in multi-isocenter intensity modulated radiotherapy for nasopharyngeal carcinoma with small multileaf collimator[J]. Med Dosim, 2009, 34(1):9-15.
[20]易俊林,高黎,徐国镇,等. 147例鼻咽癌调强放疗结果分析[J].中华放射肿瘤学杂志, 2008, 17(5):329-334.YI J L, GAO L, XU G Z, et al. Treatment results of intensity modulated radiotherapy for nasopharyngeal carcinoma:an analysis of 147 patients[J]. Chinese Journal of Radiation Oncology, 2008,17(5):329-334.