Background:The prognostic values of interim and post-therapy fluorine-18-fluorodeoxyglucose(^(18)F-FDG) positron emission tomography(PET) and PET/computed tomography(CT) scanning have been confirmed in several subtype...Background:The prognostic values of interim and post-therapy fluorine-18-fluorodeoxyglucose(^(18)F-FDG) positron emission tomography(PET) and PET/computed tomography(CT) scanning have been confirmed in several subtypes of lymphoma.However,its prognostic value in Burkitt's lymphoma has not been clearly defined.The aim of the present study was to assess the prognostic value of PET/CT scanning during different treatment processes of Burkitt's lymphoma.Methods:A total of 29 adult patients with newly diagnosed Burkitt's lymphoma were retrospectively involved in this study;of them,23 patients underwent baseline PET/CT,15 patients underwent mid-therapy PET/CT after 1-4 cycles of chemotherapy,and 17 patients underwent post-therapy PET/CT after all planned first-line chemotherapy cycles.Mid-therapy and post-therapy PET/CT results(positive vs.negative) were visually interpreted according to the criteria of the International Harmonization Project.The reduction in the maximum standardizes uptake values(ASUVmax)of 25%,50%,and 75%were regarded as cutoff points.Overall survival(OS) and progression-free survival(PFS) were regarded as the major endpoints.Results:The median OS and PFS were 27.6 months(range 6.5-78.3 months) and 27.2 months(range 3.0-78.3 months),respectively.The median SUVmax of the baseline PET/CT was 18.3(range 1.6-35.9),whereas the median SUVmax of the mid-therapy and post-therapy PET/CT decreased to 4.0(range 0-17.6) and 3.0(range 0-14.5),respectively.The patients' Eastern Cooperative Oncology Group(ECOG) scores(<2 vs.≥2) were significantly associated with the baseline PET/CT SUVmax.The mid-therapy and post-therapy PET/CT results(positive vs.negative) showed no significant association with OS or PFS.The optimal cutoff ASUVmax from the baseline to the post-therapy PET/CT that could predict a change in OS in patients with Burkitt's lymphoma was 50%(P = 0.019).Conclusions:^(18)F-FDG uptake was intense in Burkitt's lymphoma,and there was a significant reduction in SUVmax during the interim and post-therapy PET/CT procedures.A ASUVmax of greater than 50%was a favorable cutoff point to predict the OS of Burkitt's lymphoma patients.展开更多
To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,an...To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,and the mesoscopic pore structures of salt rock before and after fatigue tests and under different cycle numbers were measured using CT scanning instrument.Based on the test results,the effects of the cycle number and the upper-limit stress on the evolution of cracks,pore morphology,pore number,pore volume,pore size,plane porosity,and volume porosity of salt rock were analyzed.The failure path of salt rock specimens under cyclic loading was analyzed using the distribution law of plane porosity.The damage variable of salt rock under cyclic loading was defined on basis of the variation of volume porosity with cycle number.In order to describe the fatigue deformation behavior of salt rock under cyclic loading,the nonlinear Burgers damage constitutive model was further established.The results show that the model established can better reflect the whole development process of fatigue deformation of salt rock under cyclic loading.展开更多
The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory e...The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.展开更多
目的分析放射性荧光脱氧葡萄糖(18F-FDG)正电子发射断层扫描(PET)/计算机断层扫描(CT)显像在肺癌术前分期诊断及复发转移预测中的应用价值。方法 回顾性分析2022年9月至2023年6月期间80例初诊肺癌患者的临床和影像学数据,所有患者均在术...目的分析放射性荧光脱氧葡萄糖(18F-FDG)正电子发射断层扫描(PET)/计算机断层扫描(CT)显像在肺癌术前分期诊断及复发转移预测中的应用价值。方法 回顾性分析2022年9月至2023年6月期间80例初诊肺癌患者的临床和影像学数据,所有患者均在术前1周内进行了18F-F DG P ET/CT显像检查,并在术后3~6个月内进行了复查,监测复发或转移情况。术前的TNM分期和术后的复发转移情况均以手术病理结果或临床随访结果为金标准进行评估。结果术前分期诊断中,18F-FD(G P ET/CT显像的T分期、N分期和M分期的符合率分别为86.59%、81.93%和100%,一致性检验Kappa值分别为0.834、0.793和1.000。术后的复发转移检测中,18F-FDG PET/CT显像在术后6个月内成功检出了22例(88.00%)的复发转移病例,其诊断灵敏度为88.00%,特异度为100.00%。结论18F-FDG PET/CT显像在肺癌术前分期以及术后复发转移的预测中具有较高的准确性和可靠性,该方法可以为临床提供有效的参考信息,有助于医生制定更准确的治疗方案和更有效的随访策略。展开更多
基金supported by grants from the National Natural Science Foundation of China(No.81472759 and 81301903)Guangdong Natural Science Foundation(No.S2013010016331)+3 种基金Science and Technology Planning Project of Guangdong Province,China(No. 2014J4100163)Science and Technology Planning Project of Guangzhou, China(No.2013B021800142)Fundamental Research Funds for the Central Universities(No.10ykpy36)Research Award Funds for Outstanding Young Researchers in Sun Yat-sen University Cancer Center
文摘Background:The prognostic values of interim and post-therapy fluorine-18-fluorodeoxyglucose(^(18)F-FDG) positron emission tomography(PET) and PET/computed tomography(CT) scanning have been confirmed in several subtypes of lymphoma.However,its prognostic value in Burkitt's lymphoma has not been clearly defined.The aim of the present study was to assess the prognostic value of PET/CT scanning during different treatment processes of Burkitt's lymphoma.Methods:A total of 29 adult patients with newly diagnosed Burkitt's lymphoma were retrospectively involved in this study;of them,23 patients underwent baseline PET/CT,15 patients underwent mid-therapy PET/CT after 1-4 cycles of chemotherapy,and 17 patients underwent post-therapy PET/CT after all planned first-line chemotherapy cycles.Mid-therapy and post-therapy PET/CT results(positive vs.negative) were visually interpreted according to the criteria of the International Harmonization Project.The reduction in the maximum standardizes uptake values(ASUVmax)of 25%,50%,and 75%were regarded as cutoff points.Overall survival(OS) and progression-free survival(PFS) were regarded as the major endpoints.Results:The median OS and PFS were 27.6 months(range 6.5-78.3 months) and 27.2 months(range 3.0-78.3 months),respectively.The median SUVmax of the baseline PET/CT was 18.3(range 1.6-35.9),whereas the median SUVmax of the mid-therapy and post-therapy PET/CT decreased to 4.0(range 0-17.6) and 3.0(range 0-14.5),respectively.The patients' Eastern Cooperative Oncology Group(ECOG) scores(<2 vs.≥2) were significantly associated with the baseline PET/CT SUVmax.The mid-therapy and post-therapy PET/CT results(positive vs.negative) showed no significant association with OS or PFS.The optimal cutoff ASUVmax from the baseline to the post-therapy PET/CT that could predict a change in OS in patients with Burkitt's lymphoma was 50%(P = 0.019).Conclusions:^(18)F-FDG uptake was intense in Burkitt's lymphoma,and there was a significant reduction in SUVmax during the interim and post-therapy PET/CT procedures.A ASUVmax of greater than 50%was a favorable cutoff point to predict the OS of Burkitt's lymphoma patients.
基金supported by the National Natural Science Foundation of China(No.52178354).
文摘To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,and the mesoscopic pore structures of salt rock before and after fatigue tests and under different cycle numbers were measured using CT scanning instrument.Based on the test results,the effects of the cycle number and the upper-limit stress on the evolution of cracks,pore morphology,pore number,pore volume,pore size,plane porosity,and volume porosity of salt rock were analyzed.The failure path of salt rock specimens under cyclic loading was analyzed using the distribution law of plane porosity.The damage variable of salt rock under cyclic loading was defined on basis of the variation of volume porosity with cycle number.In order to describe the fatigue deformation behavior of salt rock under cyclic loading,the nonlinear Burgers damage constitutive model was further established.The results show that the model established can better reflect the whole development process of fatigue deformation of salt rock under cyclic loading.
基金supported by the National Natural Science Foundation of China(Grant Nos.42277150,41977219)Henan Provincial Science and Technology Research Project(Grant No.222102320271).
文摘The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.
文摘目的分析放射性荧光脱氧葡萄糖(18F-FDG)正电子发射断层扫描(PET)/计算机断层扫描(CT)显像在肺癌术前分期诊断及复发转移预测中的应用价值。方法 回顾性分析2022年9月至2023年6月期间80例初诊肺癌患者的临床和影像学数据,所有患者均在术前1周内进行了18F-F DG P ET/CT显像检查,并在术后3~6个月内进行了复查,监测复发或转移情况。术前的TNM分期和术后的复发转移情况均以手术病理结果或临床随访结果为金标准进行评估。结果术前分期诊断中,18F-FD(G P ET/CT显像的T分期、N分期和M分期的符合率分别为86.59%、81.93%和100%,一致性检验Kappa值分别为0.834、0.793和1.000。术后的复发转移检测中,18F-FDG PET/CT显像在术后6个月内成功检出了22例(88.00%)的复发转移病例,其诊断灵敏度为88.00%,特异度为100.00%。结论18F-FDG PET/CT显像在肺癌术前分期以及术后复发转移的预测中具有较高的准确性和可靠性,该方法可以为临床提供有效的参考信息,有助于医生制定更准确的治疗方案和更有效的随访策略。
