Background： Volumetric-modulated arc therapy （VMAT） can only be implemented on the new generation linacs such as the Varian Trilogy（R） and Elekta Synergy（R）.This prevents most existing linacs from delivering VM...Background： Volumetric-modulated arc therapy （VMAT） can only be implemented on the new generation linacs such as the Varian Trilogy（R） and Elekta Synergy（R）.This prevents most existing linacs from delivering VMAT.The purpose of this study was to investigate the feasibility of using a conventional linear accelerator delivering constant dose rate and constant angular spacing intensity-modulated arc therapy （CDR-CAS-IMAT） for treating cervical cancer.Methods： Twenty patients with cervical cancer previously treated with intensity-modulated radiation therapy （IMRT） using Varian Clinical 23EX were retreated using CDR-CAS-IMAT.The planning target volume （PTV） was set as 50.4 Gy in 28 fractions.Plans were evaluated based on the ability to meet the dose volume histogram.The homogeneity index （HI）, target volume conformity index （CI）, the dose to organs at risk, radiation delivery time, and monitor units （MUs） were also compared.The paired t-test was used to analyze the two data sets.All statistical analyses were performed using SPSS 19.0 software.Results： Compared to the IMRT group, the CDR-CAS-IMAT group showed better PTV CI （0.85 ＆#177; 0.03 vs.0.81 ＆#177; 0.03, P =0.001）, clinical target volume CI （0.46 ＆#177; 0.05 vs.0.43 ＆#177; 0.05, P =0.001）, HI （0.09＆#177;0.02 vs.0.11 ＆#177; 0.02, P =0.005） and D95 （5196.33 ＆#177; 28.24 cGy vs.5162.63 ＆#177; 31.12 cGy, P =0.000）, and cord D2 （3743.8 ＆#177; 118.7 cGy vs.3806.2 ＆#177; 98.7 cGy, P =0.017） and rectum V40 （41.9 ＆#177; 6.1% vs.44.2 ＆#177; 4.8%, P =0.026）.Treatment time （422.7 ＆#177; 46.7 s vs.84.6 ＆#177; 7.8 s, P =0.000） and the total plan Mus （927.4 ＆#177; 79.1 vs.787.5 ＆#177; 78.5, P =0.000） decreased by a factor of 0.8 and 0.15, respectively.The IMRT group plans were superior to the CDR-CAS-IMAT group plans considering decreasing bladder V50 （17.4 ＆#177; 4.5% vs.16.6 ＆#177; 4.2%, P =0.049）, bowel V30 （39.6 ＆#177; 6.5% vs.36.6 ＆#177; 7.5%, P =0.008）, and low-dose irradiation volume;there were no significant differences in other statistical indexes.Conclusions： Patients with cervical cancer treated with CDR-CAS-IMAT using Varian Clinical 23EX can get equivalent or superior dose distribution compared to those treated with IMRT.CDR-CAS-IMAT has a less treatment time and MU, which can reduce the uncertainty factor and patient discomfort in treatment.展开更多
本文主要是对植入科学公司生产的模型3500碘-125植入治疗粒子源的一系列剂量学特征的研究。粒子源的各个剂量学参量通过使用蒙特卡罗方法计算得到。计算模型材料采用了两种等效水:固体水和液态水。粒子源的剂量学参量如剂量率常数、径...本文主要是对植入科学公司生产的模型3500碘-125植入治疗粒子源的一系列剂量学特征的研究。粒子源的各个剂量学参量通过使用蒙特卡罗方法计算得到。计算模型材料采用了两种等效水:固体水和液态水。粒子源的剂量学参量如剂量率常数、径向剂量函数和各项异性函数等的确定依照美国医学物理学家协会(American Association of Physicists in Medicine AAPM)第43次工作报告。蒙特卡罗模拟得到液态水的剂量率为0.997 cGyh-1U-1,固态水的为1.027 cGyh-1U-1。与前同类研究比较,本次研究的剂量率常数与同类研究所报道的数据较为一致。展开更多
Before clinical application of a new source, the dosimetric parameters of the source should be accu- rately determined. This work is dedicated to the Monte Carlo method to calculate dosimetric parameters as recommende...Before clinical application of a new source, the dosimetric parameters of the source should be accu- rately determined. This work is dedicated to the Monte Carlo method to calculate dosimetric parameters as recommended by the American Association of Physicists in Medicine (AAPM) TG-43 guidelines for model ADVANTAGETM palladium-103 source and, through comparison with data from another published report for the same source, presents a suggested dataset for clinical applications. From these calcula- tions, tables are presented for the radial dose function and the anisotropy function of palladium-103 brachytherapy source. The dose rate constants are found to be 0.671 (cGyh-1U-1) in liquid water and 0.673 (cGyh-1U-1) in Solid WaterTM. And the anisotropy constants in liquid water and Solid WaterTM are found to be 0.864 and 0.865 respectively. Comparison with the previous study shows that our results of dosimetric parameters are in good agreement with those measured and calculated by Meigooni et al. (2006) both in Water and Solid WaterTM.展开更多
基金This study was partially supported by a grant from the Medical Science Foundation of the Health Department of Hebei Province
文摘Background： Volumetric-modulated arc therapy （VMAT） can only be implemented on the new generation linacs such as the Varian Trilogy（R） and Elekta Synergy（R）.This prevents most existing linacs from delivering VMAT.The purpose of this study was to investigate the feasibility of using a conventional linear accelerator delivering constant dose rate and constant angular spacing intensity-modulated arc therapy （CDR-CAS-IMAT） for treating cervical cancer.Methods： Twenty patients with cervical cancer previously treated with intensity-modulated radiation therapy （IMRT） using Varian Clinical 23EX were retreated using CDR-CAS-IMAT.The planning target volume （PTV） was set as 50.4 Gy in 28 fractions.Plans were evaluated based on the ability to meet the dose volume histogram.The homogeneity index （HI）, target volume conformity index （CI）, the dose to organs at risk, radiation delivery time, and monitor units （MUs） were also compared.The paired t-test was used to analyze the two data sets.All statistical analyses were performed using SPSS 19.0 software.Results： Compared to the IMRT group, the CDR-CAS-IMAT group showed better PTV CI （0.85 ＆#177; 0.03 vs.0.81 ＆#177; 0.03, P =0.001）, clinical target volume CI （0.46 ＆#177; 0.05 vs.0.43 ＆#177; 0.05, P =0.001）, HI （0.09＆#177;0.02 vs.0.11 ＆#177; 0.02, P =0.005） and D95 （5196.33 ＆#177; 28.24 cGy vs.5162.63 ＆#177; 31.12 cGy, P =0.000）, and cord D2 （3743.8 ＆#177; 118.7 cGy vs.3806.2 ＆#177; 98.7 cGy, P =0.017） and rectum V40 （41.9 ＆#177; 6.1% vs.44.2 ＆#177; 4.8%, P =0.026）.Treatment time （422.7 ＆#177; 46.7 s vs.84.6 ＆#177; 7.8 s, P =0.000） and the total plan Mus （927.4 ＆#177; 79.1 vs.787.5 ＆#177; 78.5, P =0.000） decreased by a factor of 0.8 and 0.15, respectively.The IMRT group plans were superior to the CDR-CAS-IMAT group plans considering decreasing bladder V50 （17.4 ＆#177; 4.5% vs.16.6 ＆#177; 4.2%, P =0.049）, bowel V30 （39.6 ＆#177; 6.5% vs.36.6 ＆#177; 7.5%, P =0.008）, and low-dose irradiation volume;there were no significant differences in other statistical indexes.Conclusions： Patients with cervical cancer treated with CDR-CAS-IMAT using Varian Clinical 23EX can get equivalent or superior dose distribution compared to those treated with IMRT.CDR-CAS-IMAT has a less treatment time and MU, which can reduce the uncertainty factor and patient discomfort in treatment.
文摘本文主要是对植入科学公司生产的模型3500碘-125植入治疗粒子源的一系列剂量学特征的研究。粒子源的各个剂量学参量通过使用蒙特卡罗方法计算得到。计算模型材料采用了两种等效水:固体水和液态水。粒子源的剂量学参量如剂量率常数、径向剂量函数和各项异性函数等的确定依照美国医学物理学家协会(American Association of Physicists in Medicine AAPM)第43次工作报告。蒙特卡罗模拟得到液态水的剂量率为0.997 cGyh-1U-1,固态水的为1.027 cGyh-1U-1。与前同类研究比较,本次研究的剂量率常数与同类研究所报道的数据较为一致。
基金Supported by the National Natural Science Foundation of China (Grant Nos. 10775174 and 90206044)
文摘Before clinical application of a new source, the dosimetric parameters of the source should be accu- rately determined. This work is dedicated to the Monte Carlo method to calculate dosimetric parameters as recommended by the American Association of Physicists in Medicine (AAPM) TG-43 guidelines for model ADVANTAGETM palladium-103 source and, through comparison with data from another published report for the same source, presents a suggested dataset for clinical applications. From these calcula- tions, tables are presented for the radial dose function and the anisotropy function of palladium-103 brachytherapy source. The dose rate constants are found to be 0.671 (cGyh-1U-1) in liquid water and 0.673 (cGyh-1U-1) in Solid WaterTM. And the anisotropy constants in liquid water and Solid WaterTM are found to be 0.864 and 0.865 respectively. Comparison with the previous study shows that our results of dosimetric parameters are in good agreement with those measured and calculated by Meigooni et al. (2006) both in Water and Solid WaterTM.
