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The Association between Lower Incisal Inclination and Morphology of the Supporting Alveolar Bone—A Cone-Beam CT Study 被引量:19
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作者 Quan Yu Xiao-gang Pan Guo-ping Ji Gang Shen 《International Journal of Oral Science》 SCIE CAS CSCD 2009年第4期217-223,共7页
Aim To investigate the relationship between the positioning of the lower central incisor and physical morphology of the surrounding alveolar bone. Methodology Thirty-eight patients (18 males, 20 females), with mean ... Aim To investigate the relationship between the positioning of the lower central incisor and physical morphology of the surrounding alveolar bone. Methodology Thirty-eight patients (18 males, 20 females), with mean age of 13.4 years, were included in this study. As part of orthodontic treatment planning the patients were required to take dental Cone-beam CT (CBCT) covering the region of lower incisors, the sur- rounding alveolar bone and the mandibular symphysis. The cephalometric parameters were designed and measured to indicate the inclination of lower central incisor and physical morphology of the adjacent alveolar bone. Computer-aided descriptive statistical analysis was performed using SPSS 15.0 software package for Windows. A correlation analysis and a linear regression analysis between the incisor inclination and the alveolar bone morphology were performed. Results Significant positive correlations were found between the lower central incisor inclination and the morphological contour of the alveolar bone (P〈0.05). The lower central incisor root apex was closer to the lingual alveolar crest when it was buccally inclined. Conclusion The morphology of the alveolar bone may be affected by incisal inclination. 展开更多
关键词 cone-beam ct (CBct alveolar bone incisorinclination
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利用Cone-Beam CT探讨支抗微螺钉周围骨密度与其稳定性的关系 被引量:2
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作者 秦璐 邵奕奕 赵颖 《口腔医学研究》 CAS CSCD 2013年第6期547-550,共4页
目的:利用Cone-Beam CT测量支抗微螺钉周围骨密度值,探讨其与微螺钉稳定性的关系。方法:选取颌骨左右对称植入微螺钉后一侧松动而另一侧稳固的7名(共18枚微螺钉)正畸患者。拍摄CBCT,所得三维影像重建后用OnDemand 3DApplication软件对... 目的:利用Cone-Beam CT测量支抗微螺钉周围骨密度值,探讨其与微螺钉稳定性的关系。方法:选取颌骨左右对称植入微螺钉后一侧松动而另一侧稳固的7名(共18枚微螺钉)正畸患者。拍摄CBCT,所得三维影像重建后用OnDemand 3DApplication软件对微螺钉骨内部分周围2mm范围内骨密度(以Hounsfield Unit表示)进行测量,自身对照比较分析双侧对称部位所植入微螺钉周围骨密度测量值间的差异。结果:松动微螺钉与稳定微螺钉骨内部分周围2mm范围内骨密度无统计学差异,两侧微螺钉钉尖部1/3、钉中部1/3及钉颈部1/3周围骨密度均无统计学差异。结论:微螺钉种植支抗的稳定性与其周围骨密度间未发现明显相关性。 展开更多
关键词 微螺钉 cone-beam ct 骨密度
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Cone-beam CT技术及其在口腔正畸学中的应用进展 被引量:28
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作者 王婷 厉松 《北京口腔医学》 CAS 2011年第2期113-115,共3页
在正畸的诊断治疗过程中,Cone-beam CT已广泛应用于口腔界的各个领域,本文旨在对Cone-beamCT的原理、特点及其在口腔正畸领域中的应用进行综述,以期增加正畸医师对于Cone-beam CT的理解。
关键词 口腔正畸学 ct技术 应用 诊断治疗 正畸医师
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Detail-preserving ring artifact correction method for cone-beam CT
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作者 侯慧玲 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第2期165-170,共6页
Ring artifact is the major factor that seriously influence quality of computed tomography(CT)image reconstruction,especially in testing large-scale workpieces.To remove ring artifact quickly and efficiently,a kind of ... Ring artifact is the major factor that seriously influence quality of computed tomography(CT)image reconstruction,especially in testing large-scale workpieces.To remove ring artifact quickly and efficiently,a kind of ring artifact correction method is improved based on the post-processing CT image reconstruction in this paper.At first,transform the CT image from the rectangular coordinates into polar coordinates.Next,design multidimensional filter to filter the image and calculate the mean and variance of each filtered pixel in polar coordinates.The location of artifact point is determined by the double precision.One is the comparison of calculated variance and variance threshold,and another is the comparison of pixel value and pixel value threshold.Then,process the artifact points in a reasonable manner and do details remain to CT image in particular.At last,convert corrected polar image into rectangular coordinates.The actual experiment shows that compared with the original method,improved method can better correct the ring artifacts and keep the image details for CT images.It is a kind of practical ring artifact correction methods for subsequent processing and quantitative analysis. 展开更多
关键词 cone beam computed tomography(ct) Feldkamp-Davis-Kress(FDK)algorithm ring artifacts detail-preserving
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Slice-wise reconstruction for low-dose cone-beam CT using a deep residual convolutional neural network 被引量:4
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作者 Hong-Kai Yang Kai-Chao Liang +1 位作者 Ke-Jun Kang Yu-Xiang Xing 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第4期53-61,共9页
Because of the growing concern over the radiation dose delivered to patients, X-ray cone-beam CT(CBCT) imaging of low dose is of great interest. It is difficult for traditional reconstruction methods such as Feldkamp ... Because of the growing concern over the radiation dose delivered to patients, X-ray cone-beam CT(CBCT) imaging of low dose is of great interest. It is difficult for traditional reconstruction methods such as Feldkamp to reduce noise and keep resolution at low doses. A typical method to solve this problem is using optimizationbased methods with careful modeling of physics and additional constraints. However, it is computationally expensive and very time-consuming to reach an optimal solution. Recently, some pioneering work applying deep neural networks had some success in characterizing and removing artifacts from a low-dose data set. In this study,we incorporate imaging physics for a cone-beam CT into a residual convolutional neural network and propose a new end-to-end deep learning-based method for slice-wise reconstruction. By transferring 3D projection to a 2D problem with a noise reduction property, we can not only obtain reconstructions of high image quality, but also lower the computational complexity. The proposed network is composed of three serially connected sub-networks: a cone-to-fan transformation sub-network, a 2D analytical inversion sub-network, and an image refinement sub-network. This provides a comprehensive solution for end-to-end reconstruction for CBCT. The advantages of our method are that the network can simplify a 3D reconstruction problem to a 2D slice-wise reconstruction problem and can complete reconstruction in an end-to-end manner with the system matrix integrated into the network design. Furthermore, reconstruction can be less computationally expensive and easily parallelizable compared with iterative reconstruction methods. 展开更多
关键词 cone-beam ct Slice-wise RESIDUAL U-net Low dose Image DENOISING
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Clinically relevant human temporal bone measurements using novel high-resolution cone-beam CT 被引量:10
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作者 Jing Zou Jaakko Laahelma +1 位作者 Antti Arnisalo Ilmari Pyykko 《Journal of Otology》 CSCD 2017年第1期9-17,共9页
Objective: To test the feasibility of measuring fine temporal bone structures using a newly established cone-beam computed tomography(CBCT)system.Materials and methods: Six formalin-fixed human cadaver temporal bones ... Objective: To test the feasibility of measuring fine temporal bone structures using a newly established cone-beam computed tomography(CBCT)system.Materials and methods: Six formalin-fixed human cadaver temporal bones were imaged using a high-resolution CBCT system that has 900 frames and copper t aluminum filtration. Fine temporal bone structures, including those of the facial nerve canal and vestibular structures, were identified and measured.Results: The fine structures of the middle ear, including the tympanic membrane, tendon of the tensor tympani, cochleariform process of the semicanal of the tensor tympani, pyramidal eminence, footplate of the stapes, full path of the facial nerve within the temporal bone, supralabyrinthine space, semicircular canals, pathway of the subarcuate canal, and full path of the vestibular aqueduct, were clearly demonstrated. The vestibular aqueduct has a midpoint width of 0.4 ± 0.0 mm and opercular width of 0.5 ± 0.1 mm(mean ± SD). The length of the internal acoustic meatus was 10.6 ± 1.2 mm(mean ± SD), and the diameter of the internal acoustic meatus was 3.7 ± 0.3 mm(mean ± SD).Conclusion: This novel high-resolution CBCT system has potentially broad applications in the diagnosis of inner ear disease and in monitoring associated pathological changes, surgical planning, navigation for the ear surgery, and temporal bone training. 展开更多
关键词 ct Temporal bone ANATOMY VESTIBULE FACIAL NERVE
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Validation of a novel imaging approach using multi-slice CT and cone-beam CT to follow-up on condylar remodeling after bimaxillary surgery 被引量:7
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作者 laura ferreira pinheiro nicolielo jeroen van dessel +5 位作者 eman shaheen carolina letelier marina codari constantinus politis ivo lambrichts reinhilde jacobs 《International Journal of Oral Science》 SCIE CAS CSCD 2017年第3期139-144,共6页
The main goal of this study was to introduce a novel three-dimensional procedure to objectively quantify both inner and outer condylar remodelling on preoperative multi-slice computed tomography (MSCT) and postopera... The main goal of this study was to introduce a novel three-dimensional procedure to objectively quantify both inner and outer condylar remodelling on preoperative multi-slice computed tomography (MSCT) and postoperative cone-beam computed tomography (CBCT) images. Second, the reliability and accuracy of this condylar volume quantification method was assessed. The mandibles of 20 patients (11 female and 9 male) who underwent bimaxillary surgery were semi-automatically extracted from MSCT/CBCT scans and rendered in 3D. The resulting condyles were spatially matched by using an anatomical landmark-based registration procedure. A standardized sphere was created around each condyle, and the condylar bone volume within this selected region of interest was automatically calculated. To investigate the reproducibility of the method, inter- and intra-observer reliability was calculated for assessments made by two experienced radiologists twice five months apart in a set of ten randomly selected patients. To test the accuracy of the bone segmentation, the inner and outer bone structures of one dry mandible, scanned according to the clinical set-up, were compared with the gold standard, micro-CT. Thirty-eight condyles showed a significant (P〈O.05) mean bone volume decrease of 26.4%_ 11.4% (502.9 mm3+ 268.1 mm3). No significant effects of side, sex or age were found. Good to excellent (ICC〉 0.6) intra- and inter-observer reliability was observed for both MSCT and CBCT. Moreover, the bone segmentation accuracy was less than one voxel (0.4 mm) for MSCT (0.3 mm __. 0.2 mm) and CBCT (0.4 mm _ 0.3 mm), thus indicating the clinical potential of this method for objective follow-up in pathological condylar resorption. 展开更多
关键词 condylar resorption cone-beam computed tomography mandibular condyle multi-slice computed tomography three-dimensional imaging
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Scatter correction method for cone-beam CT based on interlacing-slit scan 被引量:3
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作者 黄魁东 张华 +2 位作者 史仪凯 张亮 徐哲 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第9期515-521,共7页
Cone-beam computed tornography (CBCT) has the notable features of high efficiency and high precision, and is widely used in areas such as medical imaging and industrial non-destructive testing. However, the presence... Cone-beam computed tornography (CBCT) has the notable features of high efficiency and high precision, and is widely used in areas such as medical imaging and industrial non-destructive testing. However, the presence of the ray scatter reduces the quality of CT images. By referencing the slit collimation approach, a scatter correction method for CBCT based on the interlacing-slit scan is proposed. Firstly, according to the characteristics of CBCT imaging, a scatter suppression plate with interlacing slits is designed and fabricated. Then the imaging of the scatter suppression plate is analyzed, and a scatter correction Calculation method for CBCT based on the image fusion is proposed, which can splice out a complete set of scatter suppression projection images according to the interlacing-slit projection images of the left and the right imaging regions in the scatter suppression plate, and simultaneously complete the scatter correction within the fiat panel detector (FPD). Finally, the overall process of scatter suppression and correction is provided. The experimental results show that this method can significantly improve the clarity of the slice images and achieve a good scatter correction. 展开更多
关键词 cone-beam computed tomography scatter correction interlacing slits image fusion
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Multiple helical scans and the reconstruction of over FOV-sized objects in cone-beam CT 被引量:1
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作者 韩玉 闫镔 +3 位作者 李磊 宇超群 李建新 包尚联 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第6期588-594,共7页
In cone-beam computed tomography (CBCT), there are often cases where the size of the specimen is larger than the field of view (FOV) (referred to as over FOV-sized (OFS)). To acquire the complete projection da... In cone-beam computed tomography (CBCT), there are often cases where the size of the specimen is larger than the field of view (FOV) (referred to as over FOV-sized (OFS)). To acquire the complete projection data for OFS objects, some scan modes have been developed for long objects and short but over-wide objects. However, these modes still cannot meet the requirements for both longitudinally long and transversely wide objects. In this paper, we propose a multiple helical scan mode and a corresponding reconstruction algorithm for both longitudinally long and transversely wide objects. The simulation results show that our model can deal with the problem and that the results are acceptable, while the OFS object is twice as long compared with the FOV in the same latitude. 展开更多
关键词 large object multiple helical scans reconstruction algorithm cone-beam computed to-mography
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An analytical simulation technique for cone-beam CT and pinhole SPECT
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作者 ZHANG Xuezhu QI Yuj in 《Nuclear Science and Techniques》 SCIE CAS CSCD 2011年第6期338-343,共6页
This study was aimed at developing an efficient simulation technique with an ordinary PC.The work involved derivation of mathematical operators,analytic phantom generations,and effective analytical projectors developi... This study was aimed at developing an efficient simulation technique with an ordinary PC.The work involved derivation of mathematical operators,analytic phantom generations,and effective analytical projectors developing for cone-beam CT and pinhole SPECT imaging.The computer simulations based on the analytical projectors were developed by ray-tracing method for cone-beam CT and voxel-driven method for pinhole SPECT of degrading blurring.The 3D Shepp-Logan,Jaszczak and Defrise phantoms were used for simulation evaluations and image reconstructions.The reconstructed phantom images were of good accuracy with the phantoms.The results showed that the analytical simulation technique is an efficient tool for studying cone-beam CT and pinhole SPECT imaging. 展开更多
关键词 锥束ct 仿真技术 SPE 针孔 ct分析 射线追踪方法 模拟技术 ct成像
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Derivative-Hilbert-Backprojection based image reconstruction from truncated projections in helical cone-beam CT
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作者 张峰 闫镔 +5 位作者 李磊 席晓琦 江桦 魏星 张翔 崔进鲜 《Nuclear Science and Techniques》 SCIE CAS CSCD 2015年第2期45-53,共9页
In helical cone-beam computed tomography(CT), Feldkamp-Davis-Kress(FDK) based image reconstruction algorithms are by far the most popular. However, artifacts are commonly met in the presence of lateral projection trun... In helical cone-beam computed tomography(CT), Feldkamp-Davis-Kress(FDK) based image reconstruction algorithms are by far the most popular. However, artifacts are commonly met in the presence of lateral projection truncation. The reason is that the ramp filter is global. To restrain the truncation artifacts, an approximate reconstruction formula is proposed based on the Derivative-Hilbert-Backprojection(DHB) framework. In the method, the first order derivative filter is followed by the Hilbert transform. Since the filtered projection values are almost zero by the first order derivative filter, the following Hilbert transform has little influence on the projection values, even though the projections are laterally truncated. The proposed method has two main advantages. First, it has comparable computational efficiency and image quality as well as the conventional helical FDK algorithm for non-truncated projections. The second advantage is that images can be reconstructed with acceptable quality and much lower computational cost in comparison to the Laplace operator based algorithm in cases with truncated projections. To point out the advantages of our method, simulations on the computer and real data experiments on our laboratory industrial cone-beam CT are conducted. The simulated and experimental results demonstrate that the method is feasible for image reconstruction in the case of projection truncation. 展开更多
关键词 图像重建算法 希尔伯特变换 锥束ct 反投影 衍生物 截短 螺旋 锥形
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Delivered Dose Verification for Lung Cancer Stereotactic Body Radiotherapy Using Cone-Beam CT
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作者 Yechao Feng Xi Liu +4 位作者 Xiang Pan Chang Hu Ning Zhan Zongda Zhu Zhenxiang Deng 《Journal of Cancer Therapy》 2021年第7期453-459,共7页
<strong>Purpose: </strong><span><span style="font-family:""><span style="font-family:Verdana;">Verified the delivered dose distribution of lung cancer Stereotacti... <strong>Purpose: </strong><span><span style="font-family:""><span style="font-family:Verdana;">Verified the delivered dose distribution of lung cancer Stereotactic </span><span><span style="font-family:Verdana;">Body Radiotherapy (SBRT) using the cone-beam CT images. </span><b><span style="font-family:Verdana;">Methods:</span></b></span><b> </b><span style="font-family:Verdana;">Twenty </span><span style="font-family:Verdana;">lung cancer patients </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">who </span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">underwent SBRT with 100 CBCT images were</span></span><span><span style="font-family:""> <span style="font-family:Verdana;">enrolled in this study. Delivered dose distributions were recalculated on</span><span style="font-family:Verdana;"> CBCT images with </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">the </span></span><span><span style="font-family:""><span style="font-family:Verdana;">deformed and non-deformed metho</span><span style="font-family:Verdana;">d</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span><span><span style="font-family:""><span style="font-family:Verdana;">, respectively. The </span><span style="font-family:Verdana;">planned and delivered dose distributions were compared using the</span><span style="font-family:Verdana;"> dose-volume histograms. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">The delivered target coverage (V100) per patient inside target volume deviated on average were 0.83% ± 0.86% and 1.38% ±</span></span></span><span><span style="font-family:""> </span></span><span><span style="font-family:""><span style="font-family:Verdana;">1.40% for Pct </span><i><span style="font-family:Verdana;">vs</span></i><span style="font-family:Verdana;">. Pcbct and Pct </span><i><span style="font-family:Verdana;">vs</span></i><span style="font-family:Verdana;">. Pdcbct, respectively. The Conformity Index (CI) and Gradient Index (GI) showed a good agreement among the plans. For the critical organs, only minor differences were observed between the planned dose and </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">the </span></span><span><span style="font-family:""><span style="font-family:Verdana;">delivered dose. </span><b><span style="font-family:Verdana;">Conclusions: </span></b><span style="font-family:Verdana;">CBCT images were </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">a </span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">useful tool for setup and dose deliver</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">y</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"> verification for lung cancer patients </span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">who </span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;">underwent SBRT.</span></span> 展开更多
关键词 Lung Cancer Stereotactic Body Radiotherapy Cone Beam ct Dose Verification
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Iodized oil uptake assessment with cone-beam CT in chemoembolization of small hepatocellular carcinomas 被引量:8
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作者 Ung Bae Jeon Jun Woo Lee +5 位作者 Ki Seok Choo Chang Won Kim Suk Kim Tae Hong Lee Yeon Joo Jeong Dae Hwan Kang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第46期5833-5837,共5页
AIM:To evaluate the utility of assessing iodized oil uptake with cone-beam computed tomography(CT)in transarterial chemoembolization(TACE)for small he-patocellular carcinoma(HCC).METHODS:Cone-beam CT provided by a bip... AIM:To evaluate the utility of assessing iodized oil uptake with cone-beam computed tomography(CT)in transarterial chemoembolization(TACE)for small he-patocellular carcinoma(HCC).METHODS:Cone-beam CT provided by a biplane flat-panel detector angiography suite was performed on eighteen patients(sixteen men and two women;41-76 years;mean age,58.9 years)directly after TACE for small HCC(26 nodules under 30 mm;mean diam-eter,11.9 mm;range,5-28 mm).The pre-procedural locations of the tumors were evaluated using tripha-sic multi-detector row helical computed tomography(MDCT).The tumor locations on MDCT and the iodized oil uptake by the tumors were analyzed on cone-beam CT and on spot image directly after the procedures.RESULTS:All lesions on preprocedural MDCT were de-tected using iodized oil uptake in the lesions on cone-beam CT(sensitivity 100%,26/26).Spot image depictediodized oil uptake in 22 of the lesions(sensitivity 85%).The degree of iodized oil uptake was overestimated(9%,2/22)or underestimated(14%,3/22)on spot image in f ive nodules compared with that of cone-beam CT.CONCLUSION:Cone-beam CT is a useful and conve-nient tool for assessing the iodized oil uptake of small hepatic tumors(< 3 cm)directly after TACE. 展开更多
关键词 CHEMOEMBOLIZATION Computed tomography Hepatocellular carcinoma LIVER
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Three-dimensional weighting reconstruction algorithm for circular cone-beam CT under large scan angles 被引量:3
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作者 Ya-Fei Yang Ding-Hua Zhang +2 位作者 Kui-Dong Huang Fu-Qiang Yang Zong-Zhao Gao 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第8期75-82,共8页
Improving imaging quality of cone-beam CT under large cone angle scan has been an important area of CT imaging research. Considering the idea of conjugate rays and making up missing data, we propose a three-dimensiona... Improving imaging quality of cone-beam CT under large cone angle scan has been an important area of CT imaging research. Considering the idea of conjugate rays and making up missing data, we propose a three-dimensional(3D) weighting reconstruction algorithm for cone-beam CT. The 3D weighting function is added in the back-projection process to reduce the axial density drop and improve the accuracy of FDK algorithm. Having a simple structure, the algorithm can be implemented easily without rebinning the native cone-beam data into coneparallel beam data. Performance of the algorithm is evaluated using two computer simulations and a real industrial component, and the results show that the algorithm achieves better performance in reduction of axial intensity drop artifacts and has a wide range of application. 展开更多
关键词 重建算法 锥束ct 三维 角度扫描 加权 性能评价 轴向强度 FDK算法
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Method for Converting Cone-Beam CT Values into Hounsfield Units for Radiation Treatment Planning
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作者 Tadanori Abe Kunihiko Tateoka +6 位作者 Yuichi Saito Takuya Nakazawa Masaki Yano Kensei Nakata Masanori Someya Masakazu Hori Koichi Sakata 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2017年第4期361-375,共15页
Cone-beam CT (CBCT) images acquired during radiation treatment can be used to recalculate the dose distribution as well as to confirm the treatment location. However, it is difficult to obtain the electron densities (... Cone-beam CT (CBCT) images acquired during radiation treatment can be used to recalculate the dose distribution as well as to confirm the treatment location. However, it is difficult to obtain the electron densities (EDs) necessary for dose calculation from CBCT images because of the effects of scatter contamination during CBCT image acquisition. This paper presents a mathematical method for converting the pixel values of CBCT images (CBCT values) into Hounsfield units (HUs) of radiation treatment simulation CT (simCT) images for use in radiation treatment planning. CBCT values are converted into HUs by matching the histograms of the CBCT values with the histograms of the HUs for each slice via linear scaling of the CBCT values. For prostate cancer and head-and-neck cancer patients, the EDs obtained from converted CBCT values (mCBCT values) show good agreement with the EDs obtained from HUs, within approximately 3.0%, and the dose calculated on the basis of CBCT images shows good agreement with the dose calculated on the basis of the simCT images, within approximately 2.0%. Because the CBCT values are converted for each slice, this conversion method can account for variation in the CBCT values associated with differences in body size, body shape, and inner tissue structures, as well as in longitudinally displaced positions from the isocenter, unlike conventional methods that use electron density phantoms. This method improves on conventional CBCT-ED conversion and shows considerable potential for improving the accuracy of radiation treatment planning using CBCT images. 展开更多
关键词 cone-beam COMPUTED TOMOGRAPHY Hounsfield Unit Electron Density Ra-diation Treatment Planning
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Cone-beam computed tomography noise reduction method based on U-Net with convolutional block attention module in proton therapy
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作者 Xing-Yue Ruan Xiu-Fang Li +4 位作者 Meng-Ya Guo Mei Chen Ming Lv Rui Li Zhi-Ling Chen 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第7期89-100,共12页
Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therap... Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved U-Net neural network named CBAM-U-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised U-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised U-Net network, sCTU-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-U-Net and the original sCTU-Net are called CBAM-SCT and U-Net-SCT images, respectively. The HU accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 HU, 64.63 HU, 52.27 dB, and 0.9919, respectively,which were superior to those of the U-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original U-Net and CBAM-U-Net on the dose calculation results. CBAM-U-Net reduced noise more effectively than sCTU-Net, particularly in high-density tissues. We proposed a CBAM-U-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-U-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future. 展开更多
关键词 Proton therapy cone-beam ct CBAM-U-Net γ-index
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优化双下肢动脉能谱CT血管造影成像方案 被引量:1
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作者 胡莹莹 张珂 +3 位作者 何辰宇 孙宏亮 王蕾 谢晟 《中国介入影像与治疗学》 北大核心 2024年第4期242-246,共5页
目的优化双下肢动脉能谱CT血管造影(CTA)成像方案。方法回顾性分析30例疑诊双下肢动脉硬化性闭塞症(ASO)患者双下肢动脉能谱CTA资料,经重建获得40~80 keV(间隔5 keV)单能量(共9种)及100 kVp混合能量图像,对比双下肢动脉在不同图像中的C... 目的优化双下肢动脉能谱CT血管造影(CTA)成像方案。方法回顾性分析30例疑诊双下肢动脉硬化性闭塞症(ASO)患者双下肢动脉能谱CTA资料,经重建获得40~80 keV(间隔5 keV)单能量(共9种)及100 kVp混合能量图像,对比双下肢动脉在不同图像中的CT值、噪声(SD)值、信噪比(SNR)及对比度噪声比(CNR);针对50、60 keV单能量和100 kVp混合能量图像质量及血管节段的可诊断性进行主观评估,观察40、45、50、60 keV单能量和100 kVp混合能量图像的自动去骨能力。结果40~80 keV范围内,随keV升高,各动脉在图像中的CT值、SD值、SNR及CNR均逐渐降低。相比100 kVp,腘动脉(PA)及其近端动脉的CT值、CNR及SNR均在40~55 keV图像中升高(P均<0.05);50~55 keV图像中SD值升高(P均<0.05),而60 keV图像中差异无统计学意义(P>0.05)。50及60 keV图像质量主观评分及可诊断动脉节段数与100 kVp差异均无统计学意义(P均>0.05)。PA以远节段的SNR及CNR在各单能量图像及100 kVp图像中差异均无统计学意义,其CT值在40~45 keV图像中、SD在40 keV图像中均高于100 kVp(P均<0.05),但SD在45 keV与100 kVp图像中差异无统计学意义(P>0.05);50 keV图像中,PA以远节段图像质量主观评分及可诊断节段数均高于60 keV及100 kVp(P均<0.05)。40 keV图像对9例(9/30,30.00%)、45 keV图像对6例(6/30,20.00%)不能自动去骨,50及60 keV、100 kVp对30例(30/30,100%)均可自动去骨。结论行双下肢动脉能谱CTA时,对PA及其近端节段以60 keV单能量成像较佳,对其以远或双下肢全程则以50 keV单能量成像较佳。 展开更多
关键词 下肢 动脉 ct血管成像 能谱ct
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基于CT技术的黄原胶加固土干湿循环条件下力学性能和微观结构劣化机制研究 被引量:1
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作者 刘瑾 车文越 +6 位作者 郝社锋 马晓凡 喻永祥 王颖 陈志昊 李婉婉 钱卫 《岩土工程学报》 EI CAS CSCD 北大核心 2024年第5期1119-1126,共8页
干湿循环对岩土体的工程特性具有重要影响。采用CT扫描技术和力学测试,对加入不同含量黄原胶(0%,0.5%,1.5%)加固的黏土在经历不同次数(0,1,4,8,12次)干湿循环作用下的力学性能和微观结构劣化机制进行了研究,得到结论:(1)黄原胶能够有效... 干湿循环对岩土体的工程特性具有重要影响。采用CT扫描技术和力学测试,对加入不同含量黄原胶(0%,0.5%,1.5%)加固的黏土在经历不同次数(0,1,4,8,12次)干湿循环作用下的力学性能和微观结构劣化机制进行了研究,得到结论:(1)黄原胶能够有效提高土体的抗压强度和耐干湿循环效果。随着黄原胶含量的增加,干湿循环作用后的强度损失逐渐减小,当循环次数从0次增加到4次时,对于加入黄原胶含量分别为0%,0.5%,1.5%的试样,抗压强度分别损失了42.75%,17.2%,14.04%。(2)加固土的抗压强度与干湿循环次数之间保持指数下降的关系,当循环次数达到4次后,随着循环次数的进一步增加,抗压强度和弹性模量均在较小的变化范围内波动。(3)随着干湿循环次数的增加,黄原胶加固土的孔隙率表现出先增加后减小的趋势,连通孔隙不断扩展,而孤立孔隙表现出先增加后减小的趋势。(4)随着试样的干燥,黄原胶在土颗粒间形成网状基质,提高土体的强度和耐干湿循环能力。 展开更多
关键词 生物聚合物 黄原胶 抗压强度 ct扫描 微观结构 劣化机制
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基于岩石CT扫描的冻融作用对花岗岩细观结构及力学强度影响研究 被引量:1
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作者 侯圣山 何箫 +6 位作者 孟宪森 陈亮 冯振 刘明学 李昂 郭长宝 吉锋 《地质力学学报》 CSCD 北大核心 2024年第3期462-472,共11页
近年来随着西部地区的基础工程建设数量及规模不断增加,西部高原地区的季节性冻融循环效应的影响也随之增强,开展冻融循环作用下岩石细观特性及强度劣化性质研究对指导西部寒区基础工程建设至关重要。首先在偏光显微镜下对岩石薄片进行... 近年来随着西部地区的基础工程建设数量及规模不断增加,西部高原地区的季节性冻融循环效应的影响也随之增强,开展冻融循环作用下岩石细观特性及强度劣化性质研究对指导西部寒区基础工程建设至关重要。首先在偏光显微镜下对岩石薄片进行观察,获取岩石的矿物成分和微结构;接着利用CT扫描技术,对冻融后的花岗岩进行扫描,对扫描图层利用阈值分割进行二值化处理,堆叠得到样品内外结构的高分辨3D数据及影像;结合分形理论计算图像计盒维数并由此对图像复杂度做出量化判断,由此对冻融循环对花岗岩内部结构演化分布特点进行分析;进而揭示其强度演化规律,探究结构演化与强度之间的关系。偏光显微镜下,岩石呈块状构造,具有似斑状粗粒不等粒花岗结构,局部见交代蠕虫结构。似斑晶矿物主要为碱性长石;其他矿物粒径0.25~4.0 mm为主,矿物成分主要为石英、斜长石、碱性长石,次要矿物为黑云母、绿帘石,副矿物有磷灰石、锆石、黄铁矿等,镜下鉴定为似斑状粗粒不等粒黑云二长花岗岩。CT扫描显示,冻融循环效应在影响花岗岩细观结构时,会导致花岗岩内部孔隙率的整体上升,但岩石渗透性变化不大,岩石渗透率仅上升0.003×10^(-3)μm^(2);内部孔隙发育不均匀,试样整体结构改变以萌生较多新的微孔隙为主。冻融循环后岩石内部结构复杂度有所下降,但岩石整体完整性仍然较好,分形维数仍保持在较高水平。分形研究显示,20次冻融循环并未导致花岗岩的结构复杂度发生较大变化,同时试样整体力学特性出现下降,黏性增加以及长期强度出现较大幅度的衰减,进入蠕变试验阶段的应变阈值提高。在评价此类原生结构较致密的岩石的安全性时,仅从结构上进行考量与实际情况往往会出现偏差,应结合必要的强度指标综合评估。岩石在经历冻融循环后,在强度更低的同时会发生更大的变形。该研究可为分形理论在岩石细观结构演化方面的应用及岩石细观结构与强度演化相关研究提供借鉴,并对高寒地区工程施工有指导意义。 展开更多
关键词 冻融循环 阈值分割 ct模型 分形维数 结构演化 长期强度
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乳腺癌患者腋窝淋巴结转移的危险因素及行X线摄影与CT检查的诊断效能分析 被引量:2
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作者 王浩宇 石文达 +1 位作者 赵晓彬 崔志新 《河北医学》 CAS 2024年第3期506-511,共6页
目的:探讨乳腺癌患者腋窝淋巴结转移的危险因素及X线与CT检查的诊断效能比较。方法:选取2021年1月至2023年5月在我院治疗的乳腺癌患者112例,分析发生和未发生腋窝淋巴结转移患者临床资料差异;同时分析X线、CT检查诊断腋窝淋巴结转移的... 目的:探讨乳腺癌患者腋窝淋巴结转移的危险因素及X线与CT检查的诊断效能比较。方法:选取2021年1月至2023年5月在我院治疗的乳腺癌患者112例,分析发生和未发生腋窝淋巴结转移患者临床资料差异;同时分析X线、CT检查诊断腋窝淋巴结转移的价值。结果:112例患者中,腋窝淋巴结转移患者32例,腋窝淋巴结转移率为28.57%;发生腋窝淋巴结转移患者组织低分化比例、组织类型为浸润性癌比例、有脉管浸润比例、肿瘤直径≥5cm比例、组织Ki-67表达≥14%比例分别为68.75%、90.63%、28.13%、31.25%和84.38%,明显高于未发生腋窝淋巴结转移患者(P<0.05);Logistic回归分析显示:分化程度、病灶组织类型、脉管浸润、Ki-67表达是乳腺癌患者发生腋窝淋巴结转移的影响因素(P<0.05);X线诊断腋窝淋巴结转移与病理结果一致性Kappa值为0.500,P<0.05,一致性较差;CT诊断腋窝淋巴结转移与病理结果一致性Kappa值为0.825,P<0.05,一致性较好;CT诊断腋窝淋巴结转移的准确性、灵敏性和阴性预测值分别为92.86%、87.50%和95.00%,明显高于X线检查(P<0.05)。结论:乳腺癌患者腋窝淋巴结转移受分化程度、病灶组织类型、脉管浸润、Ki-67表达的影响;相较于X线,CT诊断腋窝淋巴结转移的价值较高。 展开更多
关键词 乳腺癌 腋窝淋巴结转移 危险因素 X线 ct检查
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