BACKGROUND Gastric cancer(GC)is the most common malignant tumor and ranks third for cancer-related deaths among the worldwide.The disease poses a serious public health problem in China,ranking fifth for incidence and ...BACKGROUND Gastric cancer(GC)is the most common malignant tumor and ranks third for cancer-related deaths among the worldwide.The disease poses a serious public health problem in China,ranking fifth for incidence and third for mortality.Knowledge of the invasive depth of the tumor is vital to treatment decisions.AIM To evaluate the diagnostic performance of double contrast-enhanced ultrasonography(DCEUS)for preoperative T staging in patients with GC by comparing with multi-detector computed tomography(MDCT).METHODS This single prospective study enrolled patients with GC confirmed by preoperative gastroscopy from July 2021 to March 2023.Patients underwent DCEUS,including ultrasonography(US)and intravenous contrast-enhanced ultrasonography(CEUS),and MDCT examinations for the assessment of preoperative T staging.Features of GC were identified on DCEUS and criteria developed to evaluate T staging according to the 8th edition of AJCC cancer staging manual.The diagnostic performance of DCEUS was evaluated by comparing it with that of MDCT and surgical-pathological findings were considered as the gold standard.RESULTS A total of 229 patients with GC(80 T1,33 T2,59 T3 and 57 T4)were included.Overall accuracies were 86.9%for DCEUS and 61.1%for MDCT(P<0.001).DCEUS was superior to MDCT for T1(92.5%vs 70.0%,P<0.001),T2(72.7%vs 51.5%,P=0.041),T3(86.4%vs 45.8%,P<0.001)and T4(87.7%vs 70.2%,P=0.022)staging of GC.CONCLUSION DCEUS improved the diagnostic accuracy of preoperative T staging in patients with GC compared with MDCT,and constitutes a promising imaging modality for preoperative evaluation of GC to aid individualized treatment decision-making.展开更多
In recent years, cooling technology for liquid xenon(LXe) detectors has advanced driven by the development of dark matter(DM) detectors with target mass in the 100–1000 kg range. The next generation of DM detectors b...In recent years, cooling technology for liquid xenon(LXe) detectors has advanced driven by the development of dark matter(DM) detectors with target mass in the 100–1000 kg range. The next generation of DM detectors based on LXe will be in the 50,000 kg(50 t)range requiring more than 1 k W of cooling power. Most of the prior cooling methods become impractical at this level.For cooling a 50 t scale LXe detector, a method is proposed in which liquid nitrogen(LN2) in a small local reservoir cools the xenon gas via a cold finger. The cold finger incorporates a heating unit to provide temperature regulation. The proposed cooling method is simple, reliable, and suitable for the required long-term operation for a rare event search. The device can be easily integrated into present cooling systems, for example the ‘‘Cooling Bus’ ’employed for the Panda X I and II experiments. It is still possible to cool indirectly with no part of the cooling or temperature control system getting in direct contact with the clean xenon in the detector. Also, the cooling device can be mounted at a large distance, i.e., the detector is cooled remotely from a distance of 5–10 m. The method was tested in a laboratory setup at Columbia University to carry out different measurements with a small LXe detector and behaved exactly as predicted.展开更多
In radar systems of automatic detection, an estimate of background clutter power is used to set the detection threshold. An interference saturated environment is frequently encountered in these systems (multiple targe...In radar systems of automatic detection, an estimate of background clutter power is used to set the detection threshold. An interference saturated environment is frequently encountered in these systems (multiple target situations). Therefore, the detection of signals in such an environment becomes one of the most important problems to be solved. The double-threshold algorithm is one of the more interesting detectors used in these situations. While the first threshold operation ensures that the calculation of the detection (second) threshold is based on a set of samples which is free of strong interferers and is therefore much more representative of the noise level, the second threshold is used to declare the presence or the absence of the radar target. The object of the present paper is to analyze the performance of such type of CFAR schemes when the radar receiver contains a noncoherent integrator amongst its basic elements. It is found that the processor detectabil ity loss is very low and the performance degradation, caused by interferers is quite small even if the number of outlying targets is large, given that the first threshold is properly chosen.展开更多
A novel Micro-pattern gaseous detector （MPGD）, thick GEM with electrodes made of a resistive material （RETGEM） is presented. In this paper we mainly investigate the energy resolution of a RETGEM in Ar＋CO2 with di...A novel Micro-pattern gaseous detector （MPGD）, thick GEM with electrodes made of a resistive material （RETGEM） is presented. In this paper we mainly investigate the energy resolution of a RETGEM in Ar＋CO2 with different gas mixtures. The results indicate that an energy resolution 30% in single and double mode can be obtained. The existence of an optimum energy resolution is discussed.展开更多
Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to t...Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to tackle this issue,an advanced process called double SOI has been developed.A prototype chip CPIXTEG3b adopting this new process was designed and characterized.While optimization concerning the double-SOI design and testing of the single pixel were already presented in a separate publication,this paper focuses on its noise performance of the full matrix and X-ray detection utilizing a synchrotron photon beam.Methods Equivalent noise charge(ENC)of the full pixel matrix was measured with electrical pulse tests.The threshold dispersion was minimized by the DAC tuning in each individual pixel.As a photon-counting X-ray imager,noise count accumulated up to 1 h was measured.Detection efficiency was measured with a micro-focused beam as well as a flat field generated by the X-ray scattering on a glassy carbon at the KEK PF beam line 14A.Results The typical ENC is 52 e−and the sigma of threshold dispersion is 10 e−over the full matrix.A merit of“zero”noise count is also demonstrated,which is consistent with the low ENC.The prototype chip has been tested with microbeam and used to measure the beam profile to be with a full width of 50µm at 2.4%of the maximum height.Both sensor depletion and charge sharing between neighboring pixels have been carefully characterized,providing insights for further development.The homogeneity of response to X-ray photons has been demonstrated in the flat field test.This work has drawn a final conclusion to the solution of digital pickup issue and opened a promising prospect in low-noise and high-resolution X-ray imaging.展开更多
在铁磁管道环境下,同频窄带噪声中的微弱瞬态极低频信号的估计与检测问题是管道机器人跟踪定位中最为重要的科学问题之一。为实现窄带噪声中的微弱瞬态信号的有效检测,分析了接收线圈在不同空间姿态下的信号特点,针对信号与窄带噪声相...在铁磁管道环境下,同频窄带噪声中的微弱瞬态极低频信号的估计与检测问题是管道机器人跟踪定位中最为重要的科学问题之一。为实现窄带噪声中的微弱瞬态信号的有效检测,分析了接收线圈在不同空间姿态下的信号特点,针对信号与窄带噪声相位上的区别以及信号包络的形态,建立了相位反相的双峰指数函数数学模型;应用非线性最小二乘估计,实现了该数学模型和真实信号之间的拟合;通过仿真和实验验证了该数学模型与真实信号的高度匹配性,并应用蒙特卡洛仿真分析了该模型参数估计的性能;使用所建立的数学模型,构建了平均功率检测器和瞬时最大功率检测器,通过分析比较极低频发射机在不同移动速度和接收信噪比条件下的检测性能,得出了两种检测器的特点和适用范围,并指出在现有工程背景下平均功率检测器的优势。实验证明,相位反相信息对同频窄带噪声中的信号检测非常重要,平均功率检测器在低信噪比条件下的检测性能良好。在信噪比为0.05 d B、虚警概率设为1%时,该检测器的检测概率达98.8%。展开更多
基金This study was reviewed and approved by the Ethics Committee of Sun Yat-sen University Cancer Center(Approval No.B2023-219-03).
文摘BACKGROUND Gastric cancer(GC)is the most common malignant tumor and ranks third for cancer-related deaths among the worldwide.The disease poses a serious public health problem in China,ranking fifth for incidence and third for mortality.Knowledge of the invasive depth of the tumor is vital to treatment decisions.AIM To evaluate the diagnostic performance of double contrast-enhanced ultrasonography(DCEUS)for preoperative T staging in patients with GC by comparing with multi-detector computed tomography(MDCT).METHODS This single prospective study enrolled patients with GC confirmed by preoperative gastroscopy from July 2021 to March 2023.Patients underwent DCEUS,including ultrasonography(US)and intravenous contrast-enhanced ultrasonography(CEUS),and MDCT examinations for the assessment of preoperative T staging.Features of GC were identified on DCEUS and criteria developed to evaluate T staging according to the 8th edition of AJCC cancer staging manual.The diagnostic performance of DCEUS was evaluated by comparing it with that of MDCT and surgical-pathological findings were considered as the gold standard.RESULTS A total of 229 patients with GC(80 T1,33 T2,59 T3 and 57 T4)were included.Overall accuracies were 86.9%for DCEUS and 61.1%for MDCT(P<0.001).DCEUS was superior to MDCT for T1(92.5%vs 70.0%,P<0.001),T2(72.7%vs 51.5%,P=0.041),T3(86.4%vs 45.8%,P<0.001)and T4(87.7%vs 70.2%,P=0.022)staging of GC.CONCLUSION DCEUS improved the diagnostic accuracy of preoperative T staging in patients with GC compared with MDCT,and constitutes a promising imaging modality for preoperative evaluation of GC to aid individualized treatment decision-making.
基金the Ministry of Science and Technology of China(No.2016YFA0400301)the grants for the XENON Dark Matter Project。
文摘In recent years, cooling technology for liquid xenon(LXe) detectors has advanced driven by the development of dark matter(DM) detectors with target mass in the 100–1000 kg range. The next generation of DM detectors based on LXe will be in the 50,000 kg(50 t)range requiring more than 1 k W of cooling power. Most of the prior cooling methods become impractical at this level.For cooling a 50 t scale LXe detector, a method is proposed in which liquid nitrogen(LN2) in a small local reservoir cools the xenon gas via a cold finger. The cold finger incorporates a heating unit to provide temperature regulation. The proposed cooling method is simple, reliable, and suitable for the required long-term operation for a rare event search. The device can be easily integrated into present cooling systems, for example the ‘‘Cooling Bus’ ’employed for the Panda X I and II experiments. It is still possible to cool indirectly with no part of the cooling or temperature control system getting in direct contact with the clean xenon in the detector. Also, the cooling device can be mounted at a large distance, i.e., the detector is cooled remotely from a distance of 5–10 m. The method was tested in a laboratory setup at Columbia University to carry out different measurements with a small LXe detector and behaved exactly as predicted.
文摘In radar systems of automatic detection, an estimate of background clutter power is used to set the detection threshold. An interference saturated environment is frequently encountered in these systems (multiple target situations). Therefore, the detection of signals in such an environment becomes one of the most important problems to be solved. The double-threshold algorithm is one of the more interesting detectors used in these situations. While the first threshold operation ensures that the calculation of the detection (second) threshold is based on a set of samples which is free of strong interferers and is therefore much more representative of the noise level, the second threshold is used to declare the presence or the absence of the radar target. The object of the present paper is to analyze the performance of such type of CFAR schemes when the radar receiver contains a noncoherent integrator amongst its basic elements. It is found that the processor detectabil ity loss is very low and the performance degradation, caused by interferers is quite small even if the number of outlying targets is large, given that the first threshold is properly chosen.
基金Supported by Knowledge Innovation Project of Chinese Academy of Sciences (KJCX1-YW-004,YFKJCX3.SYW.N5)Major State Basic Research Developing Program (2008CB817702)
文摘A novel Micro-pattern gaseous detector （MPGD）, thick GEM with electrodes made of a resistive material （RETGEM） is presented. In this paper we mainly investigate the energy resolution of a RETGEM in Ar＋CO2 with different gas mixtures. The results indicate that an energy resolution 30% in single and double mode can be obtained. The existence of an optimum energy resolution is discussed.
基金This work is supported by the National Nature Science Foundation of China,Grant Nos.11375226 and 11575220.
文摘Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to tackle this issue,an advanced process called double SOI has been developed.A prototype chip CPIXTEG3b adopting this new process was designed and characterized.While optimization concerning the double-SOI design and testing of the single pixel were already presented in a separate publication,this paper focuses on its noise performance of the full matrix and X-ray detection utilizing a synchrotron photon beam.Methods Equivalent noise charge(ENC)of the full pixel matrix was measured with electrical pulse tests.The threshold dispersion was minimized by the DAC tuning in each individual pixel.As a photon-counting X-ray imager,noise count accumulated up to 1 h was measured.Detection efficiency was measured with a micro-focused beam as well as a flat field generated by the X-ray scattering on a glassy carbon at the KEK PF beam line 14A.Results The typical ENC is 52 e−and the sigma of threshold dispersion is 10 e−over the full matrix.A merit of“zero”noise count is also demonstrated,which is consistent with the low ENC.The prototype chip has been tested with microbeam and used to measure the beam profile to be with a full width of 50µm at 2.4%of the maximum height.Both sensor depletion and charge sharing between neighboring pixels have been carefully characterized,providing insights for further development.The homogeneity of response to X-ray photons has been demonstrated in the flat field test.This work has drawn a final conclusion to the solution of digital pickup issue and opened a promising prospect in low-noise and high-resolution X-ray imaging.
文摘在铁磁管道环境下,同频窄带噪声中的微弱瞬态极低频信号的估计与检测问题是管道机器人跟踪定位中最为重要的科学问题之一。为实现窄带噪声中的微弱瞬态信号的有效检测,分析了接收线圈在不同空间姿态下的信号特点,针对信号与窄带噪声相位上的区别以及信号包络的形态,建立了相位反相的双峰指数函数数学模型;应用非线性最小二乘估计,实现了该数学模型和真实信号之间的拟合;通过仿真和实验验证了该数学模型与真实信号的高度匹配性,并应用蒙特卡洛仿真分析了该模型参数估计的性能;使用所建立的数学模型,构建了平均功率检测器和瞬时最大功率检测器,通过分析比较极低频发射机在不同移动速度和接收信噪比条件下的检测性能,得出了两种检测器的特点和适用范围,并指出在现有工程背景下平均功率检测器的优势。实验证明,相位反相信息对同频窄带噪声中的信号检测非常重要,平均功率检测器在低信噪比条件下的检测性能良好。在信噪比为0.05 d B、虚警概率设为1%时,该检测器的检测概率达98.8%。
