Purpose: We performed both, dosimetric and positional accuracy verification of dynamic tumor tracking (DTT) intensity modulated radiation therapy (IMRT), with the Vero4DRT system using a moving phantom (QUASAR respira...Purpose: We performed both, dosimetric and positional accuracy verification of dynamic tumor tracking (DTT) intensity modulated radiation therapy (IMRT), with the Vero4DRT system using a moving phantom (QUASAR respiratory motion platform;QUASAR phantom) and system log files. Methods: The QUASAR phantom was placed on a treatment couch. Measurement of the point dose and dose distribution was performed for conventional IMRT, with the QUASAR phantom static and moving;for DTT IMRT, this was performed with the phantom moving for pyramid shaped, prostate, paranasal sinus, and pancreas targets. The QUASAR phantom was driven by a sinusoidal signal in the superior-inferior direction. Furthermore, predicted positional errors induced by the Vero4DRT system and mechanical positional errors of the gimbal head, were calculated using the system log files. Results and Conclusion: For DTT IMRT, the dose at the evaluation point was within 3% compared with the verification plan, and the dose distribution in the passing rates of γ was 97.9%, with the criteria of 3% dose and 3 mm distance to agreement. The position error calculated from the log files was within 2 mm, suggesting the feasibility of employing DTT IMRT with high accuracy using the Vero4DRT system.展开更多
AIM: To study the leakage-penumbra(LP) effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS: Leakage-penumbra dose profiles from 10 randomly selected pros...AIM: To study the leakage-penumbra(LP) effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS: Leakage-penumbra dose profiles from 10 randomly selected prostate IMRT plans were studied. The IMRT plans were delivered by a Varian 21 EX linear accelerator equipped with a 120-leaf multileaf collimator(MLC). For each treatment plan created by the Pinnacle3 treatment planning system,a 3-dimensional LP dose distribution generated by 5 coplanar photon beams,starting from 0o with equal separation of 72 o,was investigated. For each photon beam used in the stepand-shoot IMRT plans,the first beam segment was set to have the largest area in the MLC leaf-sequencing,and was equal to the planning target volume(PTV). The overshoot effect(OSE) and the segment positional errors were measured using a solid water phantom with Kodak(TL and X-OMAT V) radiographic films. Film dosimetric analysis and calibration were carried out using a film scanner(Vidar VXR-16). The LP dose profiles were determined by eliminating the OSE and segment positional errors with specific individual irradiations. RESULTS: A non-uniformly distributed leaf LP dose ranging from 3% to 5% of the beam dose was measured in clinical IMRT beams. An overdose at the gap between neighboring segments,represented as dose peaks of up to 10% of the total BP,was measured. The LP effect increased the dose to the PTV and surrounding critical tissues. In addition,the effectdepends on the number of beams and segments for each beam. Segment positional error was less than the maximum tolerance of 1 mm under a dose rate of 600 monitor units per minute in the treatment plans. The OSE varying with the dose rate was observed in all photon beams,and the effect increased from 1 to 1.3 Gy per treatment of the rectal intersection. As the dosimetric impacts from the LP effect and OSE may increase the rectal post-radiation effects,a correction of LP was proposed and demonstrated for the central beam profile for one of the planned beams. CONCLUSION: We concluded that the measured dosimetric impact of the LP dose inaccuracy from photon beam segment in step-and-shoot IMRT can be corrected.展开更多
目的探究医科达Agility多叶准直器直线加速器在调强放射治疗计划中的剂量学优势。方法选择采用Monaco系统的30例肿瘤患者,其中男性14例,女性16例;年龄44~69岁,平均年龄58岁;肿瘤类型,头部肿瘤5例,颈部肿瘤5例,胸部肿瘤5例,乳腺癌5例,腹...目的探究医科达Agility多叶准直器直线加速器在调强放射治疗计划中的剂量学优势。方法选择采用Monaco系统的30例肿瘤患者,其中男性14例,女性16例;年龄44~69岁,平均年龄58岁;肿瘤类型,头部肿瘤5例,颈部肿瘤5例,胸部肿瘤5例,乳腺癌5例,腹部肿瘤5例,盆腔肿瘤5例。先用MLCi2多叶准直器进行放射治疗设计(MLCi2 MLC计划)。不改变计划,再用Agility多叶准直器进行放射治疗设计(Agility MLC计划)。加速器升级成Agility多叶准直器前后调强放射治疗计划的适形度指数、均匀性指数及各类危及器官剂量的差异性进行比较。结果不同放射治疗设计下,30例癌症患者计划靶区的均匀性指数(0.13±0.07 vs 0.10±0.05)和适形度指数(0.73±0.17 vs 0.75±0.13),腹部肿瘤患者计划靶区的均匀性指数(0.12±0.09 vs 0.09±0.03)和适形度指数(0.78±0.05 vs 0.81±0.06),以及肺(V20)[(23.53±11.80)cm^(3)vs(20.85±9.23)cm^(3)]、小肠(D_(max))[(5344.67±407.89)cGy vs(5244.76±361.13)cGy]、腮腺(V_(50))[(18.34±7.72)cm^(3)vs(12.23±10.27)cm^(3)]重要危及器官差异具有统计学意义(P<0.05)。Agility多叶准直器会产生大量的孤岛野,孤岛野达到总射野数的50.0%、52.3%、55.6%,孤岛野会大幅度提高双靶区患者的靶区适形度和均匀性。结论Agility多叶准直器对肿瘤的调强放射治疗计划的靶区均匀性和危及器官的保护限制均具有优势,尤其针对腹部肿瘤和双靶区患者。展开更多
目的探讨胸部肿瘤调强放疗(IMRT)后动态心电图(DCG)改变的影响因素。方法接受IMRT的胸部肿瘤患者87例,分别于治疗前后进行24 h DCG监测,分析患者临床资料及剂量-体积直方图(DVH)参数对IMRT后DCG改变的影响。结果 IMRT后出现DCG改变37例(...目的探讨胸部肿瘤调强放疗(IMRT)后动态心电图(DCG)改变的影响因素。方法接受IMRT的胸部肿瘤患者87例,分别于治疗前后进行24 h DCG监测,分析患者临床资料及剂量-体积直方图(DVH)参数对IMRT后DCG改变的影响。结果 IMRT后出现DCG改变37例(43%),将患者临床资料及物理因素进行Logistic分析,发现性别、心脏V40和DCG改变密切相关(OR=1.64、1.25、P<0.05)。结论胸部肿瘤患者IMRT治疗后性别及心脏V40是DCG发生改变的独立危险因素。展开更多
目的探讨调强放疗(IMRT)对胸部肿瘤患者不同时间段、不同类型肿瘤、不同治疗方法动态心电图(DCG)的改变。方法接受IMRT的胸部肿瘤患者126例,按照肿瘤类型分为左肺癌组43例,左乳癌组39例,食管癌组44例,按照治疗方法分为单纯放疗组36例,...目的探讨调强放疗(IMRT)对胸部肿瘤患者不同时间段、不同类型肿瘤、不同治疗方法动态心电图(DCG)的改变。方法接受IMRT的胸部肿瘤患者126例,按照肿瘤类型分为左肺癌组43例,左乳癌组39例,食管癌组44例,按照治疗方法分为单纯放疗组36例,同步放化组46例,序贯放化组44例,分别于治疗前、后,治疗结束半年后进行24 h DCG监测,比较治疗前、治疗结束时、半年后DCG异常发生率及各组治疗前后DCG异常例数。结果偶发房(室)性心律失常、ST-T改变在治疗后较治疗前明显增加,差异有统计学意义(χ2=6.21,P=0.013;χ2=15.14,P=0.000),两者在治疗前与治疗结束半年后比较,差异无统计学意义(P>0.05);治疗前、后不同类型三组肿瘤、不同治疗方法三组患者比较,DCG异常发生例数差异均无统计学意义(P>0.05)。结论胸部肿瘤患者IMRT后DCG改变多出现在治疗早期,为可逆性的;不同类型胸部肿瘤,由于IMRT的精确性,其放疗后DCG改变相似;紫杉类+铂类化疗方案对DCG影响较小,其心脏毒性相对较低。展开更多
目的探讨胸部恶性肿瘤患者行调强放疗（IMRT）后动态心电图（DCG）变化的特点及其影响因素。方法随机选取于2009年9月~2015年3月在河北省沧州市中心医院就诊并治疗的97例胸部恶性肿瘤患者,在患者行IMRT治疗前、后行24 h DCG监测,对比分...目的探讨胸部恶性肿瘤患者行调强放疗（IMRT）后动态心电图（DCG）变化的特点及其影响因素。方法随机选取于2009年9月~2015年3月在河北省沧州市中心医院就诊并治疗的97例胸部恶性肿瘤患者,在患者行IMRT治疗前、后行24 h DCG监测,对比分析患者年龄、性别等临床资料和剂量-体积直方图（DVH）参数与患者行IMRT后DCG改变的关系。结果经IMRT治疗后,47例患者出现DCG改变（48.4%）。临床资料和DVH参数经Logistic分析显示：患者的性别和放疗心脏不同体积的参数其中心脏V40与患者行IMRT后DCG改变有关（OR=1.584、1.289,P〈0.05）。结论患者的性别和DVH参数中的心脏V40是胸部恶性肿瘤患者行调强放疗治疗后动态心电图改变的独立危险因素。展开更多
文摘Purpose: We performed both, dosimetric and positional accuracy verification of dynamic tumor tracking (DTT) intensity modulated radiation therapy (IMRT), with the Vero4DRT system using a moving phantom (QUASAR respiratory motion platform;QUASAR phantom) and system log files. Methods: The QUASAR phantom was placed on a treatment couch. Measurement of the point dose and dose distribution was performed for conventional IMRT, with the QUASAR phantom static and moving;for DTT IMRT, this was performed with the phantom moving for pyramid shaped, prostate, paranasal sinus, and pancreas targets. The QUASAR phantom was driven by a sinusoidal signal in the superior-inferior direction. Furthermore, predicted positional errors induced by the Vero4DRT system and mechanical positional errors of the gimbal head, were calculated using the system log files. Results and Conclusion: For DTT IMRT, the dose at the evaluation point was within 3% compared with the verification plan, and the dose distribution in the passing rates of γ was 97.9%, with the criteria of 3% dose and 3 mm distance to agreement. The position error calculated from the log files was within 2 mm, suggesting the feasibility of employing DTT IMRT with high accuracy using the Vero4DRT system.
基金supported by the Medical Physics Department of GRRCC,Kitchener,Ontario
文摘AIM: To study the leakage-penumbra(LP) effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS: Leakage-penumbra dose profiles from 10 randomly selected prostate IMRT plans were studied. The IMRT plans were delivered by a Varian 21 EX linear accelerator equipped with a 120-leaf multileaf collimator(MLC). For each treatment plan created by the Pinnacle3 treatment planning system,a 3-dimensional LP dose distribution generated by 5 coplanar photon beams,starting from 0o with equal separation of 72 o,was investigated. For each photon beam used in the stepand-shoot IMRT plans,the first beam segment was set to have the largest area in the MLC leaf-sequencing,and was equal to the planning target volume(PTV). The overshoot effect(OSE) and the segment positional errors were measured using a solid water phantom with Kodak(TL and X-OMAT V) radiographic films. Film dosimetric analysis and calibration were carried out using a film scanner(Vidar VXR-16). The LP dose profiles were determined by eliminating the OSE and segment positional errors with specific individual irradiations. RESULTS: A non-uniformly distributed leaf LP dose ranging from 3% to 5% of the beam dose was measured in clinical IMRT beams. An overdose at the gap between neighboring segments,represented as dose peaks of up to 10% of the total BP,was measured. The LP effect increased the dose to the PTV and surrounding critical tissues. In addition,the effectdepends on the number of beams and segments for each beam. Segment positional error was less than the maximum tolerance of 1 mm under a dose rate of 600 monitor units per minute in the treatment plans. The OSE varying with the dose rate was observed in all photon beams,and the effect increased from 1 to 1.3 Gy per treatment of the rectal intersection. As the dosimetric impacts from the LP effect and OSE may increase the rectal post-radiation effects,a correction of LP was proposed and demonstrated for the central beam profile for one of the planned beams. CONCLUSION: We concluded that the measured dosimetric impact of the LP dose inaccuracy from photon beam segment in step-and-shoot IMRT can be corrected.
文摘目的探究医科达Agility多叶准直器直线加速器在调强放射治疗计划中的剂量学优势。方法选择采用Monaco系统的30例肿瘤患者,其中男性14例,女性16例;年龄44~69岁,平均年龄58岁;肿瘤类型,头部肿瘤5例,颈部肿瘤5例,胸部肿瘤5例,乳腺癌5例,腹部肿瘤5例,盆腔肿瘤5例。先用MLCi2多叶准直器进行放射治疗设计(MLCi2 MLC计划)。不改变计划,再用Agility多叶准直器进行放射治疗设计(Agility MLC计划)。加速器升级成Agility多叶准直器前后调强放射治疗计划的适形度指数、均匀性指数及各类危及器官剂量的差异性进行比较。结果不同放射治疗设计下,30例癌症患者计划靶区的均匀性指数(0.13±0.07 vs 0.10±0.05)和适形度指数(0.73±0.17 vs 0.75±0.13),腹部肿瘤患者计划靶区的均匀性指数(0.12±0.09 vs 0.09±0.03)和适形度指数(0.78±0.05 vs 0.81±0.06),以及肺(V20)[(23.53±11.80)cm^(3)vs(20.85±9.23)cm^(3)]、小肠(D_(max))[(5344.67±407.89)cGy vs(5244.76±361.13)cGy]、腮腺(V_(50))[(18.34±7.72)cm^(3)vs(12.23±10.27)cm^(3)]重要危及器官差异具有统计学意义(P<0.05)。Agility多叶准直器会产生大量的孤岛野,孤岛野达到总射野数的50.0%、52.3%、55.6%,孤岛野会大幅度提高双靶区患者的靶区适形度和均匀性。结论Agility多叶准直器对肿瘤的调强放射治疗计划的靶区均匀性和危及器官的保护限制均具有优势,尤其针对腹部肿瘤和双靶区患者。
文摘目的探讨胸部肿瘤调强放疗(IMRT)后动态心电图(DCG)改变的影响因素。方法接受IMRT的胸部肿瘤患者87例,分别于治疗前后进行24 h DCG监测,分析患者临床资料及剂量-体积直方图(DVH)参数对IMRT后DCG改变的影响。结果 IMRT后出现DCG改变37例(43%),将患者临床资料及物理因素进行Logistic分析,发现性别、心脏V40和DCG改变密切相关(OR=1.64、1.25、P<0.05)。结论胸部肿瘤患者IMRT治疗后性别及心脏V40是DCG发生改变的独立危险因素。
文摘目的探讨调强放疗(IMRT)对胸部肿瘤患者不同时间段、不同类型肿瘤、不同治疗方法动态心电图(DCG)的改变。方法接受IMRT的胸部肿瘤患者126例,按照肿瘤类型分为左肺癌组43例,左乳癌组39例,食管癌组44例,按照治疗方法分为单纯放疗组36例,同步放化组46例,序贯放化组44例,分别于治疗前、后,治疗结束半年后进行24 h DCG监测,比较治疗前、治疗结束时、半年后DCG异常发生率及各组治疗前后DCG异常例数。结果偶发房(室)性心律失常、ST-T改变在治疗后较治疗前明显增加,差异有统计学意义(χ2=6.21,P=0.013;χ2=15.14,P=0.000),两者在治疗前与治疗结束半年后比较,差异无统计学意义(P>0.05);治疗前、后不同类型三组肿瘤、不同治疗方法三组患者比较,DCG异常发生例数差异均无统计学意义(P>0.05)。结论胸部肿瘤患者IMRT后DCG改变多出现在治疗早期,为可逆性的;不同类型胸部肿瘤,由于IMRT的精确性,其放疗后DCG改变相似;紫杉类+铂类化疗方案对DCG影响较小,其心脏毒性相对较低。
文摘目的探讨胸部恶性肿瘤患者行调强放疗（IMRT）后动态心电图（DCG）变化的特点及其影响因素。方法随机选取于2009年9月~2015年3月在河北省沧州市中心医院就诊并治疗的97例胸部恶性肿瘤患者,在患者行IMRT治疗前、后行24 h DCG监测,对比分析患者年龄、性别等临床资料和剂量-体积直方图（DVH）参数与患者行IMRT后DCG改变的关系。结果经IMRT治疗后,47例患者出现DCG改变（48.4%）。临床资料和DVH参数经Logistic分析显示：患者的性别和放疗心脏不同体积的参数其中心脏V40与患者行IMRT后DCG改变有关（OR=1.584、1.289,P〈0.05）。结论患者的性别和DVH参数中的心脏V40是胸部恶性肿瘤患者行调强放疗治疗后动态心电图改变的独立危险因素。
