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基于OCTAVIUS 1500电离室矩阵的近距离放疗相对剂量分布验证 被引量:2
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作者 霍晓庆 王颖拓 +4 位作者 刘波 吴鹏 孙丹丹 路平 苗战会 《肿瘤基础与临床》 2021年第4期327-329,共3页
目的通过OCTAVIUS 1500电离室矩阵对高剂量率近距离放疗剂量分布进行可行性验证,探讨其剂量分布的验证方法。方法首先利用井型电离室对放射源的活度进行标定,然后对放有施源器的电离室矩阵进行计算机断层扫描,图像传至放疗计划系统进行... 目的通过OCTAVIUS 1500电离室矩阵对高剂量率近距离放疗剂量分布进行可行性验证,探讨其剂量分布的验证方法。方法首先利用井型电离室对放射源的活度进行标定,然后对放有施源器的电离室矩阵进行计算机断层扫描,图像传至放疗计划系统进行计划设计,最后利用OCTAVIUS 1500电离室矩阵对剂量分布进行验证。结果本研究共设计10例3根平行管后装治疗计划,其通过率均大于90%。结论OCTAVIUS 1500电离室矩阵在近距离放疗的剂量分布验证上具有可行性,且具有操作简单、成本低、方便快捷的优势。 展开更多
关键词 近距离放疗 octavius 1500电离室矩阵 剂量分布验证
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Octavius1500电离室矩阵基于模体和CT影像剂量验证的分析 被引量:3
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作者 郭逸潇 李亚洲 +2 位作者 刘志强 缪国英 蔡宏懿 《辐射研究与辐射工艺学报》 CAS CSCD 2021年第2期35-44,共10页
利用Octavius1500电离室矩阵进行RapidArc计划剂量验证,探讨基于CT影像重建3D剂量的可行性和影响剂量重建精度的因素。选取106例不同解剖部位RapidArc计划(31例头颈、36例胸部、39例盆腔)进行模体和CT影像的验证,分析标准取3%/3 mm、3%/... 利用Octavius1500电离室矩阵进行RapidArc计划剂量验证,探讨基于CT影像重建3D剂量的可行性和影响剂量重建精度的因素。选取106例不同解剖部位RapidArc计划(31例头颈、36例胸部、39例盆腔)进行模体和CT影像的验证,分析标准取3%/3 mm、3%/2 mm、2%/2 mm和2%/1 mm(全局归一,阈值10%)。结果表明,头颈、胸部和盆腔模体计划的平均通过率为99.31%、99.86%和98.36%(3%/3 mm,p=0.308),96.74%、97.91%和95.16%(3%/2 mm,p=0.193)。36例计划用Octavius 729矩阵复测,得3%/3 mm标准1500和729的通过率均值为99.05%和96.05%(95%置信区间(CI):[98.53,99.58]%和[95.16,96.93]%),3%/2 mm是96.78%和91.09%(95%-CI:[95.57,97.99]%和[89.56,92.63]%),2%/2 mm是91.49%和83.75%(95%-CI:[88.89,94.10]%和[81.41,86.09]%),2%/1 mm是79.90%和70.86%(95%-CI:[75.66,84.14]%和[67.68,74.05]%)。Octavius系统重建3D剂量的精度可能依赖于靶区的复杂程度,剂量梯度的陡峭程度及电离室矩阵分辨率,基于治疗计划CT影像不通过点(γ>1)的分析是可行的。 展开更多
关键词 octavius1500 电离室矩阵 快速旋转调强放疗 3D剂量重建 质量保证
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The Journey of SRS: An Initial Experience of Starting Sterotactic Radiosurgery Facility at Purbanchal Cancer Hospital—First in Nepal
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作者 Birendra Kumar Yadav Karthik Nagamuthu +11 位作者 Alok Thakur Kushal Rizal Umesh Kumar Sharma Ujwal Rai Dinesh Thapa Shishir Thapa Kumar Chinnappan Amit Kumar Dubey Suraj Gurung Aman Yadav Utpalkant Kumar Ranjay Kumar 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2023年第2期37-50,共14页
Introduction: Radiotherapy (RT) is a vital cancer treatment modality for both curative and palliative purposes. Nepal is a developing country with a population of around 30 million people. Cancer affects 100 - 120 peo... Introduction: Radiotherapy (RT) is a vital cancer treatment modality for both curative and palliative purposes. Nepal is a developing country with a population of around 30 million people. Cancer affects 100 - 120 people out of every 100,000, and the figure is increasing. The number of radiation facility machines in the country is still countable in fingers. Purbanchal Cancer Hospital, Nepal is the first comprehensive cancer facility capable of performing stereotactic radiosurgery (SRS). Our facility has cutting-edge Varian Truebeam Linear Accelerators with millennium MLC, which makes SRS and SRT’S for intracranial lesions such as small benign and malignant tumors much easier. In addition to SRS, we are the pioneers of SBRT for lung using 4DCT, interstitial & intraluminal brachytherapy, RPM Gated & DIBH modalities in Nepal. Methods & Materials: The purpose of this study is to share our experience in establishing an SRS facility in the country, which includes training the RT team on the importance of process accuracy, patient selection, patient assessment, mould preparation, and describing image data acquisition, target, and organ at risk delineation on CT and MRI images, treatment planning process, and quality assurance. Results & Discussion: The plans for all SRS and SRT cases are based on target coverage, OAR sparing, hotspot inside the target, conformity index, heterogeneity index, and dose fall off. To select the final plan, we used strict passing criteria such as a conformity index Paddick (CIPaddick) more than 0.85, a falloff between 100% and 50% of less than 5.5 mm (maximum 6 mm in irregular targets), and a hotspot inside the target between 115 to 140 percent, as per clinical standards. In addition, we determined the CILomax and CIRTOG for each case. Passing criteria for verification plans are set as minimum of 95% for a 2% percentage dose difference (% DD) and a 2-mm distance to an agreement (DTA). We also gathered demographic data from patients treated in the first year, such as diagnosis, lesion size, dose fraction, heterogeneity index (HI), conformity index (CI) and gamma index. SRS/SRT treatment was successfully implemented, and over 40 patients were treated with positive clinical outcomes. Conclusion: SRS now has a wider range of alternatives, thanks to technology advancements in recent years. SRS’s dosimetric advantages have steadily been extended to extracranial locations. Purbanchal Cancer Hospital, Birtamode, Nepal established a comprehensive cancer facility with qualified workforce with the goal of providing high-quality treatment to the people of Nepal. 展开更多
关键词 Conformity Index Double Shell Positioning System Electronic Portal Imaging Device Linear Accelerator Millennium MLC octavius Detector 1500 Setup Field
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常规QA设备对脊柱转移瘤SRS/SBRT计划的验证及存在问题探讨 被引量:1
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作者 郭逸潇 刘志强 +3 位作者 李鸿岩 冯维贵 张致远 李淑萍 《中国医学物理学杂志》 CSCD 2021年第12期1464-1471,共8页
目的:对比aSi-1200 EPID与Octavius 1500电离室矩阵在6 MV非均整脊柱转移瘤计划验证中的应用,探讨可能存在的问题。方法:23例计划在全局归一方式下以不同标准和阈值行2Dγ通过率(GPR)评估,将治疗计划系统(TPS)中患者数据导入Verisoft软... 目的:对比aSi-1200 EPID与Octavius 1500电离室矩阵在6 MV非均整脊柱转移瘤计划验证中的应用,探讨可能存在的问题。方法:23例计划在全局归一方式下以不同标准和阈值行2Dγ通过率(GPR)评估,将治疗计划系统(TPS)中患者数据导入Verisoft软件重建剂量。引入不同类型和量值的误差:MLC的透射率(TF)和剂量叶片间隙(DLG)、治疗等中心和MU误差,使用GPR方法量化Octavius 1500识别这些误差的灵敏度,并通过评估靶区和危及器官(OARs)剂量学指标变化研究TF和DLG误差的临床意义。结果:与Octavius 1500矩阵相比,EPID方式在同一标准不同阈值下GPR均值更大数据离散程度更小,重建与计算的剂量体积直方图分析表明临床靶区和计划靶区D_(min)、D_(max)和D_(mean)的百分剂量偏差(DD%)较大,其中临床靶区最大DD%值为50.00%、11.31%和-8.71%,计划靶区最大DD%值为-25.86%、9.31%和-8.22%。治疗等中心和+3%、+5%的MU误差都被检测到,所有标准均未检测到TF误差,+0.3 mm的DLG误差只被2%/3 mm的标准检测到。TF值增大0.0236%模型误差和DLG增加0.3 mm模型误差均导致靶区和OARs的剂量增加,其中OARs剂量增加较明显,尤其健侧肺的V_(20)分别增加9.80%和8.85%,脊髓D_(0.1 cc)均增加5.35%。结论:使用GPR方法识别引入误差的MLC模型可靠性不够,提示鉴别TPS问题的根源需要更有效的独立质量保证方法以确保通过TPS计算得出的陡峭剂量梯度的可信度。剂量验证系统软件算法的独立验证研究是有必要的,以确定算法局限性导致的重建剂量不确定性范围。 展开更多
关键词 脊柱转移瘤 aSi-1200 EPID octavius 1500 剂量验证 透射率 剂量叶片间隙
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