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
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
This paper reported a case of fusion between an impacted third molar and a supernumerary tooth, in which a surgical intervention was carried out, with the objective of removing the dental elements. The panoramic radio...This paper reported a case of fusion between an impacted third molar and a supernumerary tooth, in which a surgical intervention was carried out, with the objective of removing the dental elements. The panoramic radiography was complemented by the Donovan＇s radiographic technique; but because of the proximity of the dental element to the mandibular ramus, it was not possible to have a final fusion diagnosis. Hence, the Cone-Beam Computed Tomography--which provides precise three- dimensional information--was used to determinate the fusion diagnosis and also to help in the surgical planning. In this case report we observed that the periapical, occlusal and panoramic were not able to show details which could only be examined through the cone-beam computed tomo- graphy.展开更多
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
Objective:Apatinib is an oral TKI targeting VEGFR-2.Single-agent apatinib treatment has been shown to produce an objective response in patients with pretreated m BC.Oral vinorelbine also holds promise as a treatment o...Objective:Apatinib is an oral TKI targeting VEGFR-2.Single-agent apatinib treatment has been shown to produce an objective response in patients with pretreated m BC.Oral vinorelbine also holds promise as a treatment of choice in patients with m BC.This study aimed to investigate the efficacy and safety of the oral vinorelbine-apatinib combination in patients with pretreated m BC.In addition,we detected gene variants in ct DNA to explore the therapeutic implications.Methods:This study enrolled patients with HER2-negative m BC who were pretreated with anthracycline/taxanes.Patients were treated with apatinib at 500 mg/425 mg daily plus oral vinorelbine 60 mg/m2 on days 1,8,and 15 of every cycle(3 weeks).The primary endpoint was PFS.The secondary endpoints were ORR,CBR,OS,and safety.Patients eligible for ct DNA detection were evaluated before and during treatment.Results:Forty patients were enrolled.The median PFS was 5.2 months(95%CI,3.4–7.0 months),and the median OS was 17.4 months(95%CI,8.0–27.0 months).The ORR was 17.1%(6/35),and the CBR was 45.7%(16/35).The most common AEs included gastrointestinal reaction,myelosuppression,and hypertension.In 20 patients,ct DNA was detected at baseline and during treatment.A significant difference was found in PFS for undetected vs.detected baseline ct DNA(13.9 months vs.3.6 months,P=0.018).Conclusions:All-oral therapy with apatinib plus vinorelbine displayed objective efficacy in patients with heavily pretreated HER2-negative m BC,with acceptable and manageable toxicity profiles.Patients with no gene variant detected and lower variant allele frequencies in ct DNA at baseline showed longer PFS.展开更多
Objective:To evaluate the value of18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the diagnosis of cervical lymph node metastasis of oral carcinoma.Methods:China national kn...Objective:To evaluate the value of18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the diagnosis of cervical lymph node metastasis of oral carcinoma.Methods:China national knowledge infrastructure, Wanfang, Chinese sci-tech journal database, PubMed, EMbase, the Cochrane Library and Web of Science were searched for18F-FDG PET/CT in cervical lymph node metastasis oral cancer. Literature screening, data extraction and literature quality evaluation were carried out independently by two researchers according to the unified classification criteria. Stata13.0 software and Meta-Disc1.4 software were used for meta-analysis.Results: A total of 14 studies with 849 cases of patients with cervical metastasis of oral cancer were included, among which 9 studies were conducted on patients, with a total of 299 patients, and 5 studies were conducted on lymph nodes, with 1965 patients with cervical lymph node proved pathologically. The results of meta analysis showed that18F-FDG PET/CT had good sensitivity and specificity in the diagnosis of cervical lymph node metastasis of oral cancer. The results showed that sensitivity = 0.81 (95% CI: 0.73-0.87), specificity = 0. 90 (95% CI: 0.83-0.94), combined likelihood ratio = 7. 9 (95% CI: 4.9-12.7), negative likelihood ratio = 0. 21 (95% CI: 0.15-0.30), diagnostic odds ratio=37 (95% CI: 20-67), and receiver operating characteristic curve =0.91 (95% CI: 0.89-0.94). Conclusions:18F-FDG PET/CT has high sensitivity and specificity in the diagnosis of cervical lymph node metastasis, and can be used as an important preoperative evaluation method for oral cancer.展开更多
基金Digital Medical Equipment Research and Development Project,Ministry of Science and Technology,China:The development of Synchrotron-based proton therapy system(2016YFC0105400).
文摘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.
文摘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.
文摘This paper reported a case of fusion between an impacted third molar and a supernumerary tooth, in which a surgical intervention was carried out, with the objective of removing the dental elements. The panoramic radiography was complemented by the Donovan＇s radiographic technique; but because of the proximity of the dental element to the mandibular ramus, it was not possible to have a final fusion diagnosis. Hence, the Cone-Beam Computed Tomography--which provides precise three- dimensional information--was used to determinate the fusion diagnosis and also to help in the surgical planning. In this case report we observed that the periapical, occlusal and panoramic were not able to show details which could only be examined through the cone-beam computed tomo- graphy.
基金supported by the National Natural Science Foundation of China(Nos.61771279,11435007)the National Key Research and Development Program of China(No.2016YFF0101304)
文摘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.
基金funded by the National Natural Science Foundation of China(Grant No.81472753 and 81672634)。
文摘Objective:Apatinib is an oral TKI targeting VEGFR-2.Single-agent apatinib treatment has been shown to produce an objective response in patients with pretreated m BC.Oral vinorelbine also holds promise as a treatment of choice in patients with m BC.This study aimed to investigate the efficacy and safety of the oral vinorelbine-apatinib combination in patients with pretreated m BC.In addition,we detected gene variants in ct DNA to explore the therapeutic implications.Methods:This study enrolled patients with HER2-negative m BC who were pretreated with anthracycline/taxanes.Patients were treated with apatinib at 500 mg/425 mg daily plus oral vinorelbine 60 mg/m2 on days 1,8,and 15 of every cycle(3 weeks).The primary endpoint was PFS.The secondary endpoints were ORR,CBR,OS,and safety.Patients eligible for ct DNA detection were evaluated before and during treatment.Results:Forty patients were enrolled.The median PFS was 5.2 months(95%CI,3.4–7.0 months),and the median OS was 17.4 months(95%CI,8.0–27.0 months).The ORR was 17.1%(6/35),and the CBR was 45.7%(16/35).The most common AEs included gastrointestinal reaction,myelosuppression,and hypertension.In 20 patients,ct DNA was detected at baseline and during treatment.A significant difference was found in PFS for undetected vs.detected baseline ct DNA(13.9 months vs.3.6 months,P=0.018).Conclusions:All-oral therapy with apatinib plus vinorelbine displayed objective efficacy in patients with heavily pretreated HER2-negative m BC,with acceptable and manageable toxicity profiles.Patients with no gene variant detected and lower variant allele frequencies in ct DNA at baseline showed longer PFS.
文摘Objective:To evaluate the value of18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the diagnosis of cervical lymph node metastasis of oral carcinoma.Methods:China national knowledge infrastructure, Wanfang, Chinese sci-tech journal database, PubMed, EMbase, the Cochrane Library and Web of Science were searched for18F-FDG PET/CT in cervical lymph node metastasis oral cancer. Literature screening, data extraction and literature quality evaluation were carried out independently by two researchers according to the unified classification criteria. Stata13.0 software and Meta-Disc1.4 software were used for meta-analysis.Results: A total of 14 studies with 849 cases of patients with cervical metastasis of oral cancer were included, among which 9 studies were conducted on patients, with a total of 299 patients, and 5 studies were conducted on lymph nodes, with 1965 patients with cervical lymph node proved pathologically. The results of meta analysis showed that18F-FDG PET/CT had good sensitivity and specificity in the diagnosis of cervical lymph node metastasis of oral cancer. The results showed that sensitivity = 0.81 (95% CI: 0.73-0.87), specificity = 0. 90 (95% CI: 0.83-0.94), combined likelihood ratio = 7. 9 (95% CI: 4.9-12.7), negative likelihood ratio = 0. 21 (95% CI: 0.15-0.30), diagnostic odds ratio=37 (95% CI: 20-67), and receiver operating characteristic curve =0.91 (95% CI: 0.89-0.94). Conclusions:18F-FDG PET/CT has high sensitivity and specificity in the diagnosis of cervical lymph node metastasis, and can be used as an important preoperative evaluation method for oral cancer.
