Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emiss...Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emission tomography/computed tomography(PET/CT).The present study aimed to evaluate the diagnostic values of PET/CT in identifying metastasis in SCLNs in NPC patients.Methods: Magnetic resonance images(MRI) and PET/CT scans for 470 patients with newly diagnosed, non-distant metastatic NPC were analyzed. Metastatic rates of SCLNs were defined by the positive number of SCLNs on PET/CT scans and total number of SCLNs on MRI scans. Receiver operating characteristic curve was applied to compare PET/CT-determined stage with MRI-determined stage.Results: In total, 2082 SCLNs were identified, with 808(38.8%) ≥ 5 and < 6 mm in diameter(group A), 526(25.3%)≥ 6 and < 7 mm in diameter(group B),374(18.0%)≥ 7 and < 8 mm in diameter(group C), 237(11.4%) ≥8 and<9 mm in diameter(group D),and 137(6.5%) ≥ 9 and <10 mm in diameter(group E).The overall metastatic rates examined by using PET/CT for groups A, B,C,D, and E were 3.5%, 8.0%, 31.3%, 60.0%, and 83.9%, respectively(P< 0.001). In level IV/Vb, the metastatic rate for nodes ≥ 8 mm was 84.6%. PET/CT examination resulted in modification of N category and overall stage for 135(28.7%) and 46(9.8%) patients, respectively. The areas under curve of MRIdetermined and PET/CT-determined overall stage were 0.659 and 0.704 for predicting overall survival, 0.661 and 0.711 for predicting distant metastasis-free survival, and 0.636 and 0.663 for predicting disease-free survival.Conclusions: PET/CT was more effective than MRI in identifying metastatic SCLNs, and the radiologic diagnostic criteria for metastatic lymph nodes in level IV/Vb should be re-defined.展开更多
Most researches involved so far in kiwifruit harvesting robot suggest the scenario of harvesting in daytime for taking advantage of sunlight.A robot operating at nighttime can overcome the problem of low work efficien...Most researches involved so far in kiwifruit harvesting robot suggest the scenario of harvesting in daytime for taking advantage of sunlight.A robot operating at nighttime can overcome the problem of low work efficiency and would help to minimize fruit damage.In addition,artificial lights can be used to ensure constant illumination instead of the variable natural sunlight for image capturing.This paper aims to study the kiwifruit recognition at nighttime using artificial lighting based on machine vision.Firstly,an RGB camera was placed underneath the canopy so that clusters of kiwifruits could be included in the images.Next,the images were segmented using an R-G color model.Finally,a group of image processing conventional methods,such as Canny operator were applied to detect the fruits.The image processing results showed that this capturing method could reduce the background noise and overcome any target overlapping.The experimental results showed that the optimal artificial lighting ranged approximately between 30-50 lx.The developed algorithm detected 88.3%of the fruits successfully.展开更多
Lung cancer is one of the most common malignant tumors. It has the highest incidence and mortality rate of all cancers worldwide. Late diagnosis of nonsmall cell lung cancer(NSCLC) is very common in clinical practice,...Lung cancer is one of the most common malignant tumors. It has the highest incidence and mortality rate of all cancers worldwide. Late diagnosis of nonsmall cell lung cancer(NSCLC) is very common in clinical practice, and most patients miss the chance for radical surgery. Thus, radiotherapy plays an indispensable role in the treatment of NSCLC. Radiotherapy technology has evolved from the classic two-dimensional approach to three-dimensional conformal and intensity-modulated radiotherapy. However, how to ensure delivery of an accurate dose to the tumor while minimizing the irradiation of normal tissues remains a huge challenge for radiation oncologists, especially due to the positioning error between fractions and the autonomous movement of organs. In recent years, image-guided radiotherapy(IGRT) has greatly increased the accuracy of tumor irradiation while reducing the irradiation dose delivered to healthy tissues and organs. This paper presents a brief review of the definition of IGRT and the various technologies and applications of IGRT. IGRT can help ensure accurate dosing of the target area and reduce radiation damage to the surrounding normal tissue. IGRT may increase the local control rate of tumors and reduce the incidence of radio-therapeutic complications.展开更多
基金supported by grants from the Science and Technology Project of Guangzhou City,China(No.14570006)the Planned Science and Technology Project of Guangdong Province,China(No.2013B020400004)
文摘Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emission tomography/computed tomography(PET/CT).The present study aimed to evaluate the diagnostic values of PET/CT in identifying metastasis in SCLNs in NPC patients.Methods: Magnetic resonance images(MRI) and PET/CT scans for 470 patients with newly diagnosed, non-distant metastatic NPC were analyzed. Metastatic rates of SCLNs were defined by the positive number of SCLNs on PET/CT scans and total number of SCLNs on MRI scans. Receiver operating characteristic curve was applied to compare PET/CT-determined stage with MRI-determined stage.Results: In total, 2082 SCLNs were identified, with 808(38.8%) ≥ 5 and < 6 mm in diameter(group A), 526(25.3%)≥ 6 and < 7 mm in diameter(group B),374(18.0%)≥ 7 and < 8 mm in diameter(group C), 237(11.4%) ≥8 and<9 mm in diameter(group D),and 137(6.5%) ≥ 9 and <10 mm in diameter(group E).The overall metastatic rates examined by using PET/CT for groups A, B,C,D, and E were 3.5%, 8.0%, 31.3%, 60.0%, and 83.9%, respectively(P< 0.001). In level IV/Vb, the metastatic rate for nodes ≥ 8 mm was 84.6%. PET/CT examination resulted in modification of N category and overall stage for 135(28.7%) and 46(9.8%) patients, respectively. The areas under curve of MRIdetermined and PET/CT-determined overall stage were 0.659 and 0.704 for predicting overall survival, 0.661 and 0.711 for predicting distant metastasis-free survival, and 0.636 and 0.663 for predicting disease-free survival.Conclusions: PET/CT was more effective than MRI in identifying metastatic SCLNs, and the radiologic diagnostic criteria for metastatic lymph nodes in level IV/Vb should be re-defined.
基金This study was financed by Project 61175099 of the National Natural Science Foundation of China.
文摘Most researches involved so far in kiwifruit harvesting robot suggest the scenario of harvesting in daytime for taking advantage of sunlight.A robot operating at nighttime can overcome the problem of low work efficiency and would help to minimize fruit damage.In addition,artificial lights can be used to ensure constant illumination instead of the variable natural sunlight for image capturing.This paper aims to study the kiwifruit recognition at nighttime using artificial lighting based on machine vision.Firstly,an RGB camera was placed underneath the canopy so that clusters of kiwifruits could be included in the images.Next,the images were segmented using an R-G color model.Finally,a group of image processing conventional methods,such as Canny operator were applied to detect the fruits.The image processing results showed that this capturing method could reduce the background noise and overcome any target overlapping.The experimental results showed that the optimal artificial lighting ranged approximately between 30-50 lx.The developed algorithm detected 88.3%of the fruits successfully.
文摘Lung cancer is one of the most common malignant tumors. It has the highest incidence and mortality rate of all cancers worldwide. Late diagnosis of nonsmall cell lung cancer(NSCLC) is very common in clinical practice, and most patients miss the chance for radical surgery. Thus, radiotherapy plays an indispensable role in the treatment of NSCLC. Radiotherapy technology has evolved from the classic two-dimensional approach to three-dimensional conformal and intensity-modulated radiotherapy. However, how to ensure delivery of an accurate dose to the tumor while minimizing the irradiation of normal tissues remains a huge challenge for radiation oncologists, especially due to the positioning error between fractions and the autonomous movement of organs. In recent years, image-guided radiotherapy(IGRT) has greatly increased the accuracy of tumor irradiation while reducing the irradiation dose delivered to healthy tissues and organs. This paper presents a brief review of the definition of IGRT and the various technologies and applications of IGRT. IGRT can help ensure accurate dosing of the target area and reduce radiation damage to the surrounding normal tissue. IGRT may increase the local control rate of tumors and reduce the incidence of radio-therapeutic complications.
