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Sparing lung tissue with virtual block method in VMAT planning for locally advanced non-small cell lung cancer

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Nuclear Science and Techniques 2022年第4期33卷 136-150页

作者： Jia-Yun Chen Da-Quan Wang Xiao-Dong Zhang Qi Fu Xue-Na Yan Kuo Men Jian-Rong Dai Nan Bi Department of Radiation Oncology National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China Department of Radiation Oncology State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat-Sen University Cancer CenterGuangzhou 510060China Department of Radiation Physics The University of Texas MD Anderson Cancer CenterHoustonTXUSA

This study aimed to exploit a new virtual block method to spare normal lung tissue in VMAT planning for patients with locally advanced non-small cell lung cancer(LA-NSCLC).The previous method was used to manually restrict the angle of the beam passing through,which ignored the location and shape of large targets that varied between different slices and did not block the beamlets precisely.Unlike the previous method,this new virtual block method was used to block the beamlets when necessary by closing the multi-leaf collimator(MLC)at prerequisite angles.The algorithm for closing the MLC depended on the thickness of the beamlets passing through the lungs and avoided only the entrance radiation beamlet.Moreover,this block can be automatically contoured.A retrospective study was performed to compare the VMAT plans with and without the virtual block method for 17 LANSCLC patients,named the block plan(B-plan)/non-block plan(N-plan).All cases were selected in this study because of the large tumor size and unmet dose constraints of the lungs.In addition to the maximum dose constraint for the virtual block,B-plans adopted identical optimization parameters to N-plans for each patient.These two types of plans were compared in terms of dosimetric indices and plan scores.The results were statistically analyzed using the Wilcoxon nonparametric signed-rank test.B-plans have advantages in the following dosimetric metrics that have statistical significance(p<0.05):(1)lower V_(5)/V_(10)/D_(mean)/normal tissue complication probability(NTCP)of total lungs;(2)reductions in V_(5)/V_(10)for the contralateral lung;(3)decrease in Dmean/V_(40)of the heart;(4)decrease in esophagus V_(40);(5)reductions in Dmean,V_(5)/V_(10) of normal tissue.B-plans(82.51±7.07)achieved higher-quality scores than N-plans(80.74±7.22).The new virtual block spared the lungs as well as other normal structures in VMAT planning for LA-NSCLC.Thus,the block method may decrease the risk of radiation-related toxicity in patients.

关键词： Virtual block VMAT Normal tissue sparing Lung cancer

Effect of Swirl Preset Vorticity on Combustion Performance of Lobe Nozzle Combustor Chamber

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第5期36卷 828-837页

作者： WANG Lijun JIANG Jintao YUAN Weiwei men kuo XU Yijun College of Energy and Environment ShenyangShenyang Aerospace University

To improve the combustor performance of multi-point injection combustion,lobe nozzle design was applied to the aero-engine model combustor,by presetting the swirl through a certain twisted angle of the edge of the lobe outlet.Numerical simulation in combination with modelling test is used in this paper.The effects of swirl vorticity presetting onto the vortex structure,the characteristics of combustion temperature field,the combustor exit temperature field quality,the combustion efficiency,and the NOx emissions of multi-point injection combustion chamber are investigated.Compared with the conventional vortex flow at the lobe outlet edge,the results of numerical simulation and water modelling test of the swirl vorticity presetting show that the swirl presetting can efficiently enhance the range and intensity of the lobe-induced vorticities.Besides,it can improve the uniformity of the combustion temperature in the combustor chamber,together with the reduced emissions of the pollutant NOx.Moreover,compared with the conventional lobe nozzle chamber,the swirl vortex presetting can effectively improve its combustion performance.The flow simulation test results demonstrate the fluid vortex structure in the combustion chamber and validate the simulation results.

关键词： lobe nozzle vortex structure multi-point injection combustor chamber combustion performance combustion characteristics

Numerical Investigation of Flow and Aerothermodynamic Characteristics in a Scramjet Flowpath with Tare Condition

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Numerical Investigation of Flow and Aerothermodynamic Charac...

Facile synthesis of bimodal macroporous g-C_3N_4/SnO_2 nanohybrids with enhanced photocatalytic activity

第六届空天动力联合会议暨中国航天第三专业信息网第四十二...

作者： Lijun Wang Weiwei Yuan Yijun Xu Kuo Men Jingpeng Fan College of Energy and Environment Shenyang Aerospace University

The HIFiRE 2(The Hypersonic International Flight Research Experimentation Flight 2) flowpath have been investigated by a Shear Stress Transport(SST) turbulent model in present work. The simulation results were compared to experimental data of the ground test, wherein the results show the validation of the simulation results. Flow separations, due to shock wave-turbulent boundary layer interactions(SBLI), were analyzed in detail. The inlet Mach number has been involved in the investigations, which has an important effect on ultrasonic flowfield and separation bubble size of the boundary layer. Besides, the simulation results indicated that with the increasing inlet Mach number, the separation region decreased and the locations moved downstream. In addition, the aerodynamic heating effect, namely, the influence on the ultrasonic flow, was analyzed, with its influences of various inlet Mach numbers being evaluated. The results show that after the aerodynamic heating dissipation source term added in the governing equations, the flow field temperature rises significantly.

关键词： Flow separation aerodynamic heating effect boundary layer thickness numerical simulation

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Science Bulletin 2019年第1期64卷 44-53页

作者： Yingzhi Chen Wenhao Li Dongjian Jiang Kuo Men Zhen Li Ling Li Shizheng Sun Jingyuan Li Zheng-Hong Huang Lu-Ning Wang School of Materials Science and Engineering University of Science and Technology Beijing State Key Laboratory of Advanced Materials for Smart Sensing General Research Institute for Non-Ferrous Metals Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

It is of vital importance to construct highly interconnected,macroporous photocatalyst to improve its efficiency and applicability in solar energy conversion and environment remediation.Graphitic-like C_3N_4(g-C_3N_4),as an analogy to two-dimensional(2D)graphene,is highly identified as a visible-lightresponsive polymeric semiconductor.Moreover,the feasibility of g-C_3N_4 in making porous structures has been well established.However,the preparation of macroporous g-C_3N_4 with abundant porous networks and exposure surface,still constitutes a difficulty.To solve it,we report a first facile preparation of bimodal macroporous g-C_3N_4 hybrids with abundant in-plane holes,which is simply enabled by in-situ modification through thermally treating the mixture of thiourea and SnCl_4(pore modifier)after rotary evaporation.For one hand,the formed in-plane macropores endow the g-C_3N_4 system with plentiful active sites and short,cross-plane diffusion channels that can greatly speed up mass transport and transfer.For another,the heterojunctions founded between g-C_3N_4 and SnO_2 consolidate the electron transfer reaction to greatly reduce the recombination probability.As a consequence,the resulted macroporous gC_3N_4/SnO_2 nanohybrid had a high specific surface area(SSA)of 44.3 m^2/g that was quite comparable to most nano/mesoporous g-C_3N_4 reported.The interconnected porous network also rendered a highly intensified light absorption by strengthening the light penetration.Together with the improved mass transport and electron transfer,the macroporous g-C_3N_4/SnO_2 hybrid exhibited about 2.4-fold increment in the photoactivity compared with pure g-C_3N_4.Additionally,the recyclability of such hybrid could be guaranteed after eight successive uses.

关键词： Highly macroporous g-C3N4 Nanohybrid Interconnected network Photocatalysis

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牙周病患者种植治疗的相关风险因素

临床医药文献电子杂志 2018年第53期5卷 196-197页

作者：门阔北方医院口腔科

牙周病作为口腔疾病之一,在临床上具有很高的发病率,是一种比较常见的口腔科疾病,主要发生在牙周组织上。基于患者不重视牙周病的早期症状,致使牙周组织长时间的处于感染与发炎状态,导致炎症发作反复,在一定程度上已经对患者的日常生活... 详细信息

牙周病作为口腔疾病之一,在临床上具有很高的发病率,是一种比较常见的口腔科疾病,主要发生在牙周组织上。基于患者不重视牙周病的早期症状,致使牙周组织长时间的处于感染与发炎状态,导致炎症发作反复,在一定程度上已经对患者的日常生活与工作造成炎症影响,给患者所造成的痛苦十分巨大。

关键词：牙周病种植治疗风险因素

基于4D-CT高通气功能肺组织避让的胸部肿瘤放疗计划可行性研究

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中华放射医学与防护杂志 2024年第2期44卷 105-110页

作者：刘志强田源门阔戴建荣国家癌症中心、国家肿瘤临床医学研究中心、中国医学科学院北京协和医学院肿瘤医院放疗科北京100021

目的建立基于4D-CT肺通气功能图像的胸部肿瘤高通气功能肺避让(HVFLA)的放疗计划设计流程,确定HVFLA的放疗计划策略,为胸部肿瘤患者开展HVFLA放疗临床试验提供支持。方法基于前期已经建立的4D-CT肺通气功能图像深度学习模型,搭建计算平... 详细信息

目的建立基于4D-CT肺通气功能图像的胸部肿瘤高通气功能肺避让(HVFLA)的放疗计划设计流程,确定HVFLA的放疗计划策略,为胸部肿瘤患者开展HVFLA放疗临床试验提供支持。方法基于前期已经建立的4D-CT肺通气功能图像深度学习模型,搭建计算平台将其融入放疗计划流程,进一步回顾性入组10例行4D-CT模拟定位的胸部肿瘤患者,根据建立的模型获取每位患者的4D-CT肺通气功能图像,根据肺通气量相对值高低自动将肺通气功能区域三等分为高、中和低通气功能肺,并导入Pinnacle3治疗计划系统。对于每位患者,根据靶区处方剂量和危及器官的剂量限值要求,采用容积旋转调强技术,分别设计临床计划和HVFLA计划,要求每个计划均满足临床要求,其中,HVFLA计划增加限制高功能肺的优化条件。通过比较靶区、危及器官(双肺、心脏和脊髓)和高功能肺的剂量学参数评价计划,剂量学参数包括靶区的D2、D98和平均剂量,双肺和高功能肺的V_(5)、V_(10)、V_(20)、V_(30)和平均剂量,心脏的V_(30)、V40和平均剂量,脊髓的D1 cm^(3)等。采用配对t检验的方法对两组计划统计分析。结果临床计划和HVFLA计划的靶区和危及器官均满足临床要求,HVFLA计划高功能肺的平均剂量、V_(5)、V_(10)、V_(20)和V_(30)平均分别减少1.2 Gy、5.9%、4.2%、2.6%和2.3%,均具有统计学意义(t=-8.07、4.02、-6.02、-7.06、-6.77,P0.05)。结论建立了基于4D-CT肺通气功能图像的高功能肺避让的放疗计划设计流程,HVFLA计划可以显著降低高功能肺的受照剂量,双肺、心脏和脊髓受照剂量无显著变化。HVFLA放疗计划策略可行,可以为胸部肿瘤患者开展HVFLA放疗提供支持。

关键词： 4D-CT肺通气功能肺功能避让放疗计划深度学习

利用深度反卷积神经网络自动勾画放疗危及器官

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中国医学物理学杂志 2018年第3期35卷 256-259页

作者：门阔戴建荣国家癌症中心/中国医学科学院北京协和医学院肿瘤医院北京100021

目的:勾画危及器官是放射治疗中非常重要的常规工作。然而,目前的人工勾画非常耗时,而且依赖于医生的知识和经验。为此,本研究提出一种深度反卷积神经网络,用于自动和精确地勾画危及器官。方法:深度反卷积神经网络是一个用于自动分割的... 详细信息

目的:勾画危及器官是放射治疗中非常重要的常规工作。然而,目前的人工勾画非常耗时,而且依赖于医生的知识和经验。为此,本研究提出一种深度反卷积神经网络,用于自动和精确地勾画危及器官。方法:深度反卷积神经网络是一个用于自动分割的端到端框架。实验使用了230例头颈部患者的数据,在其中随机选择了184例作为训练集,用于调制自动分割模型的参数,其余46例用作测试集评估方法的性能。用于分割的危及器官包括脑干、脊髓、左腮腺、右腮腺、左颞叶、右颞叶、甲状腺、喉、气管9个危及器官。自动分割精度的量化指标使用戴斯相似性系数和豪斯多夫距离。结果:所有危及器官自动分割的戴斯相似性系数值均在0.70以上(平均值为0.81),豪斯多夫距离值在5.0 mm内(平均值为4.3mm),表明本研究提出的自动分割方法能准确地分割危及器官。结论:利用深度反卷积神经网络建立了一种自动分割危及器官的方法,可以得到较准确的结果,为放射治疗流程自动化提供了技术支持。

关键词：深度学习自动分割放射治疗危及器官勾画深度反卷积神经网络

航空发动机燃烧室叉排波瓣喷嘴的分级喷射及气动特性

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过程工程学报 2021年第5期21卷 506-515页

作者：王力军门阔徐义俊沈阳航空航天大学能源与环境学院辽宁沈阳110136

搭建了由13个波瓣喷嘴采用5×5叉排方式布置的航空发动机分级燃烧室水模型实验台,通过改变各喷嘴的分级喷射方式实现不同的工作载荷。对30%及巡航两种载荷下的模型燃烧室,分别采用2级和3级两种燃烧组织方式下的空气动力学流场特性进行... 详细信息

搭建了由13个波瓣喷嘴采用5×5叉排方式布置的航空发动机分级燃烧室水模型实验台,通过改变各喷嘴的分级喷射方式实现不同的工作载荷。对30%及巡航两种载荷下的模型燃烧室,分别采用2级和3级两种燃烧组织方式下的空气动力学流场特性进行了水模拟示踪实验和数值模拟研究。对两种分级燃烧方式,通过实验和数值模拟研究了改变两种载荷下的油气比时,各级波瓣喷嘴所诱发的复杂涡系结构和涡量的大小、形态、相互作用和演变规律等气动特性。结果表明,两种分级喷射方式的涡系结构均可分为初始段、过渡段和发展段;各涡系之间历经了从独立到合并重组、再变成新涡系等演变和相互作用过程;增加油气比对两种分级喷射的过渡段影响均较大。空气模型、水模型流场的计算结果与实验结果吻合良好,验证了研究结果的可行性和可信度。

关键词：波瓣喷嘴分级喷射方式涡系结构水模实验气动特性数值模拟

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波瓣喷嘴径向分级燃烧室的燃烧性能研究

Transactions of Nanjing University of Aeronautics and Astronautics 2022年第5期39卷 619-636页

作者：王力军范荆鹏门阔徐义俊沈阳航空航天大学能源与环境学院沈阳110136

为了探究波瓣喷嘴径向分级方式对流场组织方式的影响,搭建了13点波瓣喷嘴径向分级燃烧室冷态水模实验台。对比辛辛那提大学测试的一系列燃烧羟基发光实验,选取空载、部分载荷、巡航和起飞4种对应的工况,对当量比、燃料喷射方式和燃料喷... 详细信息

为了探究波瓣喷嘴径向分级方式对流场组织方式的影响,搭建了13点波瓣喷嘴径向分级燃烧室冷态水模实验台。对比辛辛那提大学测试的一系列燃烧羟基发光实验,选取空载、部分载荷、巡航和起飞4种对应的工况,对当量比、燃料喷射方式和燃料喷射比例等因素下波瓣喷嘴径向分级燃烧室内的流场涡系结构、涡量值、燃烧多物量场以及燃烧特性,进行了数值研究。结果表明:在不同影响因素下,波瓣燃烧室的羟基火焰场变化规律与旋流燃烧室羟基发光实验变化规律基本相同,但其火焰场形状存在较大差别。局部当量比对燃烧室的相关燃烧性能影响较大。较低当量比、3级空气和燃料喷射方式以及将先导回路燃料流逐渐转移到外部回路的条件下,燃烧室的温场、火焰场分布比较均匀,出口温度场品质较好,燃烧效率较高,NO_(X)排放量比较低,与冷态实验结果基本符合。冷态实验结果说明了流场组织方式对燃烧组织方式影响的重要性,同时也验证了计算结果的可靠性。

关键词：波瓣喷嘴径向分级燃烧室气动特性燃烧特性