目的:建立一种可以对TomoTherapy治疗计划剂量进行验证的方法。方法:根据IAEA TRS 277号报告提供的水下吸收剂量测量计算的基本原理,采用待检的TomoTherapy辐射源以及在权威计量部门检定过的0.65 cc Farmer电离室,参照交叉校准的方法将...目的:建立一种可以对TomoTherapy治疗计划剂量进行验证的方法。方法:根据IAEA TRS 277号报告提供的水下吸收剂量测量计算的基本原理,采用待检的TomoTherapy辐射源以及在权威计量部门检定过的0.65 cc Farmer电离室,参照交叉校准的方法将标准量值传递给0.015 cc针尖电离室测量系统。之后采用固体水球型模体对治疗计划剂量进行检测和验证。结果:采用所建立的方法,剂量检测结果与治疗计划剂量相对偏差分别为1.35%、-2.30%、2.88%和0,皆小于±3%。结论:采用本研究所建立的方法可以与设备生产厂家的剂量治疗计划、检测结果进行比对、核查和控制,对于TomoTherapy项目的防护与应用质量检测具有重要的现实意义。展开更多
目的通过研究不同密度模体创建的CT值密度曲线(Image Value to Density Table,IVDT)对剂量计算精度的影响,探讨如何在Tomotherapy计划系统中正确创建IVDT。方法分别用Gammex和CIRS两种密度模体创建立应的IVDT表,其中以是否含有空气密度...目的通过研究不同密度模体创建的CT值密度曲线(Image Value to Density Table,IVDT)对剂量计算精度的影响,探讨如何在Tomotherapy计划系统中正确创建IVDT。方法分别用Gammex和CIRS两种密度模体创建立应的IVDT表,其中以是否含有空气密度点和在CT值-100~100 HU范围内是否包含除水以外的物质密度点分别创建IVDT表。调用不同IVDT表设计4组调强计划,同时生成7组剂量传输验证计划(Delivery Quality Assurance,DQA),测量上述11组调强计划的剂量偏差并进行配对t检验判断IVDT表是否符合要求。结果IVDT表中含有-100~100 HU计划组剂量偏差为1.55%±0.9%,与标准计划组剂量偏差比,有统计学差异(P<0.01),同理,不含空气密度点组的剂量偏差也有明显剂量学差异。7组DQA计划中调用CIRS IVDT Abdo(-100~100 HU)、Gammex IVDT Abdo(standard)的5组DQA计划剂量偏差,无统计学差异(P>0.05);调用CIRS IVDT Abdo(-100~100 HU)的2组DQA计划平均剂量偏差均为1.77%±1%,与对照组剂量偏差相比,有统计学差异。结论创建IVDT表时需要确保CT值在-100~100 HU范围内除水以外不含任何其他物质密度点,同时曲线中应该加入空气密度点,此两点对剂量计算精度影响较大。展开更多
TomoTherapy HD放射治疗系统的产热部件包括加速管、磁控管、固态调制器、高压电源、微波循环控制器等[1-2]。这些部件只有在恒温条件下才能保证稳定工作。因此,温度控制系统(themal control system,TCS)是TomoTherapy HD放射治疗系统...TomoTherapy HD放射治疗系统的产热部件包括加速管、磁控管、固态调制器、高压电源、微波循环控制器等[1-2]。这些部件只有在恒温条件下才能保证稳定工作。因此,温度控制系统(themal control system,TCS)是TomoTherapy HD放射治疗系统的重要组成部分,其稳定性直接影响着射频和束流部件的寿命及整机系统的故障率。本文首先介绍TomoTherapy HD放射治疗系统的TCS工作原理,然后对TCS的常见故障及维修过程进行总结,以供参考。展开更多
Objective： To evaluate the short-term clinical outcomes of intracranial germinoma patients treated with craniospinal irradiation （CSI） using helical tomotherapy （HT） system in our center. Methods： Twenty-three p...Objective： To evaluate the short-term clinical outcomes of intracranial germinoma patients treated with craniospinal irradiation （CSI） using helical tomotherapy （HT） system in our center. Methods： Twenty-three patients who were treated with CSI in our center from January 2008 to July 2012 were collected, with an average age of 20. M1 of the patients＇ CSI used the HT system. The total doses were 27-36 Gy/15-20 F （1.5-2 Gy per fraction）, and total local doses were 46-60 Gy/30-50 F （5 fractions per week）. M1 female patients for CSI were treated with left-right parallel-opposed field irradiation to protect their ovarian functions. Median follow-up time was 30.9 months （range, 5-67 months）. The SPSS19.0 software was used, and the overall survival （OS） was calculated using the Kaplan-Meier method. Results： Among 17 patients with assessable tumors, 9 cases （52.9%） were CR, 7 cases （41.2%） were PR, and 1 case （5.9%） was SD. Hematological toxicity was the severest side-effect occurred in the procedure of CSI. The level 1-4 acute leukopenia were 8.7%, 30.4%, 34.8% and 21.7% and the level 1-4 acute thrombopenia were 8.7%, 30.4%, 21.7% and 8.7%, respectively. Conclusions： For primary intracranial germinomas, HT can be used to implement CSI for simplifying radiotherapy procedures, improving radiotherapy accuracy, enhancing protection of peripheral organs at risk （ORA） and guaranteeing therapeutic effects. With the acceptable acute and long-term toxicity, CSI using HT in intracranial germinoma patients can be a safe and alternative mode.展开更多
Whole brain radiotherapy (WBRT) remains the standard management of breast cancer patients with brain metastases, allowing for symptomatic improvement and good local control in most patients. However, its results remai...Whole brain radiotherapy (WBRT) remains the standard management of breast cancer patients with brain metastases, allowing for symptomatic improvement and good local control in most patients. However, its results remain suboptimal in terms of both efficacy and toxicity. In highly selected breast cancer patients, stereotaxic radiotherapy demonstrates a very good local control with a low toxicity. With the purpose of improving the efficacy/toxicity ratio, we report the association of integrated boost with WBRT in a breast cancer patient with brain metastases. Two and a half years after completion of helical tomotherapy (HT), the patient experienced clinical and radiological complete remission of her brain disease. No delayed toxicity occurred and the patient kept her hair without need of radiosurgical procedure. The HT provided a high dosimetric homogeneity, delivering integrated radiation boosts, and avoiding critical structures involved in long-term neurological toxicity. Further assessment is required and recruitment of breast cancer patients into clinical trials is encouraged.展开更多
Purpose: Craniospinal axis irradiation (CSI) is a method of treating various central nervous system malignancies. The large target volume typically includes entire spinal cord and whole brain. Dosimetric comparison wa...Purpose: Craniospinal axis irradiation (CSI) is a method of treating various central nervous system malignancies. The large target volume typically includes entire spinal cord and whole brain. Dosimetric comparison was performed between tomotherapy, volumetric modulated arc therapy (VMAT), and 3D conformal radiation therapy (3D-CRT) for CSI. Methods and Materials: Five (n = 5) CSI patients were planned using 3D-CRT, VMAT, and tomotherapy (normalized such that 95% of PTV received at least 23.4 Gy in 13 fractions). Plans were compared using PTV conformity number (CN) and homogeneity index (HI), normal tissue (NT) dose statistics, integral dose, and treatment time. Results: On average, tomotherapy plans showed higher CN (0.932 vs. 0.860 and 0.672 for SmartArc and 3D-CRT). In terms of HI, VMAT plans consistently showed better dose homogeneity (1.07 vs. 1.15 and 1.13 for tomotherapy and 3D-CRT). SmartArc delivered lower maximum dose for majority of NT, but higher mean dose. 3D-CRT plans delivered higher maximum dose but lower mean dose to NT. Conclusions: SmartArc treatments achieved better PTV homogeneity and reduced maximum dose to NT. Tomotherapy showed better target conformity, but 3D-CRT was shown to reduce mean dose to NT. Integral doses were similar between treatment modalities, but tomotherapy treatment times were much longer.展开更多
介绍了TomoTherapy Hi.Art放射治疗系统的基本组成及多叶光栅(multi-leaf collimator,MLC)的工作原理,详细分析了单片MLC故障、MLC初始化失败故障、MLC over travelled故障等产生的原因并给出了具体的排除方法,为同行维修类似故障提供...介绍了TomoTherapy Hi.Art放射治疗系统的基本组成及多叶光栅(multi-leaf collimator,MLC)的工作原理,详细分析了单片MLC故障、MLC初始化失败故障、MLC over travelled故障等产生的原因并给出了具体的排除方法,为同行维修类似故障提供参考。展开更多
Objective: The aim of this study was to evaluate the functional characteristics of ArcCheck? array detectors and the application for Tomotherapy IMRT plan verification. Method and Materials: The basic character of the...Objective: The aim of this study was to evaluate the functional characteristics of ArcCheck? array detectors and the application for Tomotherapy IMRT plan verification. Method and Materials: The basic character of the ArcCheck applying on Tomotherapy system was tested. The diode testing procedures included the followings: The short term reproducibility, linearity, dose rate dependence, the profile measurement compared to ion chamber. The effect of insert on gamma passing rate was also studied. A total number of 602 Tomotherapy Delivery Quality Assurance (DQA) plans were retrospectively analyzed to obtain the action limit results with statistical significance evaluation. Results: The short term reproducibility, linearity, dose rate dependence, profile to ion chamber correlation and clinical application were all compared with satisfactory outcome with this device. If anterior diode points were properly calibrated with machine absolute output, then there was no significant difference between the ArcCheck phantom with and without insert on gamma passing rate. The average passing rate was 97.5% and the recommend action level was established at 92% based on the 602 patients’ clinical data with 95% confidence level criteria. Conclusion: This comprehensive study shows that ArcCheck is an accurate and efficient device for quality assurance of Tomotherapy with remarkable consistency of 3D volume analysis of arc therapy.展开更多
文摘Objective： To evaluate the short-term clinical outcomes of intracranial germinoma patients treated with craniospinal irradiation （CSI） using helical tomotherapy （HT） system in our center. Methods： Twenty-three patients who were treated with CSI in our center from January 2008 to July 2012 were collected, with an average age of 20. M1 of the patients＇ CSI used the HT system. The total doses were 27-36 Gy/15-20 F （1.5-2 Gy per fraction）, and total local doses were 46-60 Gy/30-50 F （5 fractions per week）. M1 female patients for CSI were treated with left-right parallel-opposed field irradiation to protect their ovarian functions. Median follow-up time was 30.9 months （range, 5-67 months）. The SPSS19.0 software was used, and the overall survival （OS） was calculated using the Kaplan-Meier method. Results： Among 17 patients with assessable tumors, 9 cases （52.9%） were CR, 7 cases （41.2%） were PR, and 1 case （5.9%） was SD. Hematological toxicity was the severest side-effect occurred in the procedure of CSI. The level 1-4 acute leukopenia were 8.7%, 30.4%, 34.8% and 21.7% and the level 1-4 acute thrombopenia were 8.7%, 30.4%, 21.7% and 8.7%, respectively. Conclusions： For primary intracranial germinomas, HT can be used to implement CSI for simplifying radiotherapy procedures, improving radiotherapy accuracy, enhancing protection of peripheral organs at risk （ORA） and guaranteeing therapeutic effects. With the acceptable acute and long-term toxicity, CSI using HT in intracranial germinoma patients can be a safe and alternative mode.
文摘Whole brain radiotherapy (WBRT) remains the standard management of breast cancer patients with brain metastases, allowing for symptomatic improvement and good local control in most patients. However, its results remain suboptimal in terms of both efficacy and toxicity. In highly selected breast cancer patients, stereotaxic radiotherapy demonstrates a very good local control with a low toxicity. With the purpose of improving the efficacy/toxicity ratio, we report the association of integrated boost with WBRT in a breast cancer patient with brain metastases. Two and a half years after completion of helical tomotherapy (HT), the patient experienced clinical and radiological complete remission of her brain disease. No delayed toxicity occurred and the patient kept her hair without need of radiosurgical procedure. The HT provided a high dosimetric homogeneity, delivering integrated radiation boosts, and avoiding critical structures involved in long-term neurological toxicity. Further assessment is required and recruitment of breast cancer patients into clinical trials is encouraged.
文摘Purpose: Craniospinal axis irradiation (CSI) is a method of treating various central nervous system malignancies. The large target volume typically includes entire spinal cord and whole brain. Dosimetric comparison was performed between tomotherapy, volumetric modulated arc therapy (VMAT), and 3D conformal radiation therapy (3D-CRT) for CSI. Methods and Materials: Five (n = 5) CSI patients were planned using 3D-CRT, VMAT, and tomotherapy (normalized such that 95% of PTV received at least 23.4 Gy in 13 fractions). Plans were compared using PTV conformity number (CN) and homogeneity index (HI), normal tissue (NT) dose statistics, integral dose, and treatment time. Results: On average, tomotherapy plans showed higher CN (0.932 vs. 0.860 and 0.672 for SmartArc and 3D-CRT). In terms of HI, VMAT plans consistently showed better dose homogeneity (1.07 vs. 1.15 and 1.13 for tomotherapy and 3D-CRT). SmartArc delivered lower maximum dose for majority of NT, but higher mean dose. 3D-CRT plans delivered higher maximum dose but lower mean dose to NT. Conclusions: SmartArc treatments achieved better PTV homogeneity and reduced maximum dose to NT. Tomotherapy showed better target conformity, but 3D-CRT was shown to reduce mean dose to NT. Integral doses were similar between treatment modalities, but tomotherapy treatment times were much longer.
文摘Objective: The aim of this study was to evaluate the functional characteristics of ArcCheck? array detectors and the application for Tomotherapy IMRT plan verification. Method and Materials: The basic character of the ArcCheck applying on Tomotherapy system was tested. The diode testing procedures included the followings: The short term reproducibility, linearity, dose rate dependence, the profile measurement compared to ion chamber. The effect of insert on gamma passing rate was also studied. A total number of 602 Tomotherapy Delivery Quality Assurance (DQA) plans were retrospectively analyzed to obtain the action limit results with statistical significance evaluation. Results: The short term reproducibility, linearity, dose rate dependence, profile to ion chamber correlation and clinical application were all compared with satisfactory outcome with this device. If anterior diode points were properly calibrated with machine absolute output, then there was no significant difference between the ArcCheck phantom with and without insert on gamma passing rate. The average passing rate was 97.5% and the recommend action level was established at 92% based on the 602 patients’ clinical data with 95% confidence level criteria. Conclusion: This comprehensive study shows that ArcCheck is an accurate and efficient device for quality assurance of Tomotherapy with remarkable consistency of 3D volume analysis of arc therapy.
