首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
目的 :比较肺部<5cm病灶5野调强放射治疗(5-field intensity modulated radiotherapy,5F-IMRT),容积调强放射治疗(volume modulated arc therapy,VMAT)立体定向放射治疗(stereotactic body radiotherapy, SBRT)计划的剂量参数,观察两种放疗设计方法在计划靶区和正常组织剂量。方法 :对收治的56例(共68个病灶)采用大分割立体定向放射治疗肺部<5cm病灶,设计处方计划靶区剂量的SBRT计划(IMRT和VMAT),处方剂量500cGy*10fx包括95%PTV,对两种计划的适形度指数(conformity index,CI)、均匀指数(homogeneity index,HI)、全肺平均剂量以及肺V_5,V_(10),V_(20),V_(30),以及串联器官脊髓、食管最大受量进行比较。结果 :5F-IMRT与VMAT计划的PTVmax, PTVDmean和PTVmin差异无统计学意义。靶区CI和HI值比较VMAT均优于5F-IMRT。全肺V_5和全肺平均受量比较,VMAT显著低于5F-IMRT,组间差异有统计学意义,而V_(10),V_(20)和V_(30)两种方式差异无统计学意义。两种放疗计划患侧肺受量V_5,V_(10),V_(20),V_(30)和患侧肺平均剂量值差异无统计学意义。健侧肺组织V_5值VMAT显著低于5F-IMRT,差异有统计学意义,V_(10),V_(20),V_(30),健侧肺平均肺剂量差异无统计学意义。食管和脊髓最高剂量差异无统计学意义。结论:5F-IMRT和VMAT计划可满足临床要求,VMAT计划的靶区适形度更优。对于小体积肺癌病灶,综合考虑可优先选择VMAT。  相似文献   

2.
FDS团队发展了剂量引导实时验证系统KylinRay-DGRT,该系统集射野透射影像采集、射野透射剂量标定、三维剂量重建、剂量评价、计划重优化等功能于一体,可进行强度和三维剂量验证,并引导物理师对放疗计划进行精确修正,从而有效地保证病人受照剂量的精准性。本文对KylinRay-DGRT的总体设计和关键技术方法进行了介绍;采用美国医学物理学家协会(AAPM)TG119号报告中的"模拟C形靶区"测试例题对KylinRay-DGRT进行正确性测试举例,结果表明KylinRay-DGRT重建的剂量与参考TPS计算的计划剂量,以及实测剂量的符合率达到94.8%以上;采用头颈部肿瘤病例对KylinRay-DGRT进行了临床验证,结果表明KylinRay-DGRT重建的剂量满足临床要求。  相似文献   

3.
目的 :通过与标准流程制作的4D放疗计划剂量分布对比分析,探讨四维计划设计过程简化可行性。方法 :选取原发性肝癌患者10例,每例患者都采用两种方案进行4D放疗计划设计,分别定义为准4D计划和4D计划。两种方案基于相同的4D轮廓勾画方式、射野方向和处方剂量,准4D计划在参考时相上进行布野及射野优化,而4D计划在各个时相上各自进行优化,然后变形叠加到参考时相。最终对比分析两种方案的剂量差异。结果 :在肝癌危及器官保护和处方剂量提升方面,4D计划都略优于准4D计划,但无统计学意义差异。结论 :临床应用肝癌的四维放射治疗技术,可以对4D计划优化过程进行部分简化,提高该技术临床应用的可操作性。但对于个别呼吸幅度较大或靶区与危及器官结构相对复杂患者,需要后续研究中进一步探讨。  相似文献   

4.
目的:探讨术前三维适形放疗联合FOLFOX方案治疗直肠癌的临床疗效及治疗安全性。方法 :选取2008年2月~2012年1月在我科治疗而且病理证实为局部晚期直肠癌患者65例,随机分为适形放疗加化疗组(观察组)35例,常规放疗加化疗组(对照组)30例,观察并比较两组的临床疗效和不良反应情况。结果 :两组总有效率(CR+PR)分别是63.3%和82.9%。术前肿瘤分期明显降低,治疗后原诊断为T 3期的35例患者中6例降为T 1期,13例降为T 2期,16例仍为T 3期;其侵犯淋巴结均有缩小,其中12例转阴。对照组放射性膀胱炎、皮肤反应和放射性直肠炎的发生率高于观察组(P<0.05)。结论 :术前三维适形放疗联合FOLFOX方案化疗治疗局部晚期直肠癌的安全有效的方法,值得临床应用。  相似文献   

5.
本文简要介绍核通放射治疗计划系统Oncentra MasterPlan3.3的临床应用,分析该TPS在实际应用中的优缺点,并针对系统速度慢、易死机以及剂量稳定性差等相关问题提出合理实用的解决方案。  相似文献   

6.
靶器官与关键器官二维轮廓线序列的三维重建,是三维放射治疗计划系统(3 dimension therapy planning system,3D-TPS)的重要组成部分,它能帮助计划者以任意视角获取病人内部组织和病变体的大小、位置、形状等三维空间信息.本文在回顾3D Delaunay三角剖分的定义、性质和基本算法的基础上,运用可视化类库Visualization Toolkit(VTK)中封装的3D Delaunay类,编程实现了脊柱和肿瘤二维轮廓线序列的三维重建.结果表明,Delaunay三角剖分方法具有稳定、耗时少、内存占用量小等优点,对轮廓线点集的数据三维分布没有特殊限制等优点.  相似文献   

7.
探讨医用电子直线加速器检测中的使用方法和临床应用体会,并评价其性能的优缺点。直线加速器的机械精度和剂量的稳定性在使用中会出现偏差,通过前指针法和两维剂量仪对加速器的机械精度和剂量参数进行定期检测,是对放射治疗计划有效实施的有利保证。依据国家放射卫生防护相关的标准及规定的方法、国家(卫生部)确认的医用电子直线加速器的性能质控和安全性评价QA检测方法,测量了SIEMENS PRIMUS M医用电子直线加速器的主要技术指标和QA内容。每周治疗前由放疗物理工程师按照国家(卫生部)质量保证规程对直线加速器进行周检,该医用直线加速器符合国家相关标准的要求。  相似文献   

8.
本文旨在讨论肿瘤放射治疗下患者生命体征的实时同步监测方法。放射治疗是一种非常有效的肿瘤治疗方法,约70%的恶性肿瘤患者需要采用放射治疗,但是在治疗过程中,患者的生命体征需要被严密监测以确保治疗的安全性和有效性。针对放射治疗中患者安全监护系统的不完善,本文构建全方位放射治疗患者安全监护系统,加强对放射治疗中患者的监控观察。安全监护系统采用基于血氧饱和度信号的呼吸率检测技术,用血氧探头测量患者的血氧饱和度、脉率、呼吸率等重要的生命体征信息,并传输至中央监护系统,在医技工作站跨区域实时同步显示,保障了患者在放射治疗环境下的生命安全监测。  相似文献   

9.
目的 :分析术前放疗和术后放疗对软组织肉瘤患者的临床效果及并发症的影响,为治疗方案的制定提供参考依据。方法 :选择我院2010年6月至2015年6月期间收治的114例确诊为软组织肉瘤的患者,采用随机数字发将所有患者平均分为术前组57例和术后组57例,所有患者均采用常规扩大根治手术切除术,前组患者手术前给予照射总剂量为30 Gy的放射治疗,共治疗2周;术后组患者于手术后1~3周后开始放射治疗,照射总剂量为50 Gy,共治疗5周,如果患者术后有残留肿瘤灶,则增加照射剂量至60~70 Gy。结果 :术前组患者的3年生存率显著高于术后组,3年转移复发率均明显低于术后组,差异具有统计学意义(P<0.05);术前组患者的伤口愈合延迟的发生率均显著高于术后组患者,但皮肤毒性反应和关节功能障碍等并发症发生率显著低于术后组,差异均具有统计学意义(P<0.05)。结论 :术前放疗对于软组织肉瘤患者较术后放疗能够获得更高的3年生存率,减少患者术后3年的转移率和复发率,但术前放疗的患者伤口并发症发生风险高,皮肤毒性反应的发生率低,临床上应全面评估患者病情,根据肿瘤灶的大小和部位选择合适的放疗时机,以提高患者的治疗效果和安全性。  相似文献   

10.
目的 :观察肺癌患者放疗前后肺灌注显像及放疗前血浆中IL-6、TGF-β1、ACE含量变化,探讨其与放射性肺炎发生的相关性。方法 :30例肺癌患者接受三维适形放疗,放疗前后行肺灌注显像检查,比较前后两次肺灌注显像变化。放疗前采血冻存,采用酶联免疫吸附法检测血液中IL-6、TGF-β1、ACE含量。放射性肺炎根据美国肿瘤放射治疗组(RTOG)标准评定。分析治疗前后肺灌注显像变化情况及血浆IL-6、TGF-β1、ACE水平与放射性肺炎发生的相关性。结果 :30例肺癌患者中10例(33.3%)发生了≥2级放射性肺炎。肺灌注受损加重者≥2级放射性肺炎发生率为63.6%,肺灌注受损改善者≥2级放射性肺炎发生率为10.5%,差异有统计学意义。放疗前血浆TGF-β1水平高者及ACE水平低者,放疗后出现≥2级放射性肺炎比率高。放疗前后肺灌注显像变化联合放疗前血浆TGF-β1水平分组,各组间发生2级以上放射性肺炎差异有统计学意义。结论 :放疗前后肺灌注显像变化联合放疗前血浆TGF-β1水平对放射性肺炎有一定预测价值。  相似文献   

11.
An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...  相似文献   

12.
The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...  相似文献   

13.
黑棣  郑美茹 《机电工程》2016,(11):1315-1321
针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。  相似文献   

14.
The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.  相似文献   

15.
The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...  相似文献   

16.
The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....  相似文献   

17.
马立新  王宏宇 《机电工程》2015,32(1):118-122
针对传统的电力系统多目标粒子群优化算法采用权重系数法将多目标转化为单目标,从而忽视了各目标函数间的竞争关系这一问题,提出将非支配解提取法运用到电力系统多目标无功优化中,并设定了一套提取规则,以电力系统中的有功网损、电压偏差和电压稳定裕度为目标,使目标在充分竞争的情况下得出Pareto最优解,利用IEEE-14节点系统对多目标非支配解提取法的电力系统无功优化进行了仿真测试。研究结果表明,该算法一次运行可以得出多组非支配解,既有偏向单个目标的解也有兼顾所有目标的解,克服了权重系数法的盲目性和单一性,可使电力决策者根据实际问题选择最优解,具有较好的灵活性与多样性。  相似文献   

18.
A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.  相似文献   

19.
This article describes designing, implementation and tuning processes of multiple-tapped-delay-line (MTDL). Obtained MTDL can be implemented in various field-programmable-logic-devices (FPGA) devices and applied for time-to-digital-converters (TDC) construction. The task of tuning process is the tapped-delay-line (TDL) linearisation, and consists of two stages. The first stage depends on selecting an appropriate configurable-logic-block (CLB) for particular delay-segment realization and selecting proper connection between these blocks. The second tuning stage, that is essential from this article viewpoint, depends on inter CLBs connecting wires delay regulation realized directly by load regulation. The Load regulation depends on connecting an appropriate number of unused three-state-buffers or CLB inputs to the wire which delay is adjusted. Depending on the number of inputs connected to the wire its capacitance changes that influences its time-constant and finally changes its time-delay.The MTDL mathematical model, obtained characteristics and results of time-interval (TI) measurements are also presented. The derived TDL model provides information about how the particular wire delay should be changed and in which order the changes should be executed. This makes the designing process predictable and easy to carry out. Presented characteristics confirm the proper operation of presented linearisation technique. The proper operation of the whole measuring module is confirmed by obtained TIs histograms presentation.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号