Energy spectrum computed tomography multi-parameter imaging in preoperative assessment of vascular and neuroinvasive status in gastric cancer

BACKGROUND Vascular and nerve infiltration are important indicators for the progression and prognosis of gastric cancer(GC),but traditional imaging methods have some limitations in preoperative evaluation.In recent years,energy spectrum computed tomography(CT)multiparameter imaging technology has been gradually applied in clinical practice because of its advantages in tissue contrast and lesion detail display.AIM To explore and analyze the value of multiparameter energy spectrum CT imaging in the preoperative assessment of vascular invasion(LVI)and nerve invasion(PNI)in GC patients.METHODS Data from 62 patients with GC confirmed by pathology and accompanied by energy spectrum CT scanning at our hospital between September 2022 and September 2023,including 46 males and 16 females aged 36-71(57.5±9.1)years,were retrospectively collected.The patients were divided into a positive group(42 patients)and a negative group(20 patients)according to the presence of LVI/PNI.The CT values(CT40 keV,CT70 keV),iodine concentration(IC),and normalized IC(NIC)of lesions in the upper energy spectrum CT images of the arterial phase,venous phase,and delayed phase 40 and 70 keV were measured,and the slopes of the energy spectrum curves[K(40-70)]from 40 to 70 keV were calculated.Arterial Core Tip:To investigate the application value of multiparameter energy spectrum computed tomography(CT)imaging in the preoperative assessment of vascular and nerve infiltration in patients with gastric cancer(GC).The imaging data of GC patients were retrospectively analyzed to evaluate the accuracy and sensitivity of CT for identifying and quantifying vascular and nerve infiltration and for comparison with postoperative pathological results.The purpose of this study was to verify the clinical feasibility and potential advantages of multiparameter energy spectrum CT imaging in guiding preoperative diagnosis and treatment decision-making and to provide a new imaging basis for improving the diagnostic accuracy and prognosis of GC patients.

Monte Carlo simulation for bremsstrahlung and photoneutron yields in high-energy x-ray radiography

This paper reports on the results of calculations using a Monte Carlo code （MCNP5） to study the properties of photons, electrons and photoneutrons obtained in the converted target and their transportations in x-ray radiography. A comparison between measurements and calculations for bremsstrahlung and photoneutrons is presented. The radiographic rule and the effect of the collimator on the image are studied with the experimental model. The results provide exact parameters for the optimal design of radiographic layout and shielding systems.

An energy spectrum smoothing algorithm based on TCC-DEE

A smoothing algorithm for energy spectrum based on differential nonlinearity(DNL) error elimination with total counts conservation for high-energy particle detector systems is presented. It is physics based and is only determined by the DNL error of analog-to-digital converter device itself. From the experimental results, this algorithm slightly improves both noise performance and energy resolution, while greatly reduces the testing errors by almost a half compared to their original values. In addition, the reduced-x^2 statistic for evaluating the Gaussian fitting goodness is significantly reduced by almost two orders after smoothing. As a typical verification example,this algorithm is successfully applied in the ground calibration of the Low Energy X-ray Instrument onboard the Hard X-ray Modulation Telescope(HXMT-LE) satellite,lending it a powerful, nondestructive and low-cost tool for both calibration and data processing for high-energy particle detector systems.

LARGE VOLUME IONIZATION CHAMBER USED AS LABORATORY REFERENCE FOR LOW ENERGY X－RAY MEASUREMENT

A large volume spherical ionization chamber of 195 mm diameter and 0.36 mg/cm2wall thickness made from conducting carbon-fibre epoxy composite material has been developed. The mechanical intensity of the chamber is satisfactory for a good longterm volume stability. Owing to its large volume and thin wall, the chamber is sensitive to low energy photon beams and has excellent energy-response characteristics. This ionization chamber is suitable not only for a laboratory reference but also for measurement of low energy photon beam exposure rates at protection-level.

Application of Dual-Energy X-Ray Image Detection of Dangerous Goods Based on YOLOv7

X-ray security equipment is currently a more commonly used dangerous goods detection tool, due to the increasing security work tasks, the use of target detection technology to assist security personnel to carry out work has become an inevitable trend. With the development of deep learning, object detection technology is becoming more and more mature, and object detection framework based on convolutional neural networks has been widely used in industrial, medical and military fields. In order to improve the efficiency of security staff, reduce the risk of dangerous goods missed detection. Based on the data collected in X-ray security equipment, this paper uses a method of inserting dangerous goods into an empty package to balance all kinds of dangerous goods data and expand the data set. The high-low energy images are combined using the high-low energy feature fusion method. Finally, the dangerous goods target detection technology based on the YOLOv7 model is used for model training. After the introduction of the above method, the detection accuracy is improved by 6% compared with the direct use of the original data set for detection, and the speed is 93FPS, which can meet the requirements of the online security system, greatly improve the work efficiency of security personnel, and eliminate the security risks caused by missed detection.

Ion irradiation-induced structure damage to botanic samples using the ion transmission energy spectrum

In order to study the mechanism of irradiation-induced damage ofbotanic samples caused by low energy heavy ions, transmission energy spectrum mea-surement was performed. Kidney bean slice samples 100μm in thickness were irradi-ated by 50 kev N+ ions. The irradiation beam current density was about 30μA/cm2,and the irradiation ion doses were 1×1015, 1×1016, 3×1016 and 1×1017 ions@cm-2,respectively. A target set up that could greatly reduce the incident ion current densitywas designed to achieve the damage-free measurement. The 3.2 MeV H+ transmittedion energy spectrum measurement was carried out before and after the irradiation.From the transmission ion energy spectrum, it was found that the kidney bean sliceitself was structurally inhomogeneous compared with the PET films (C10HsO4). Ourresults indicated that the average mass thickness changed little when the N+ iondose was below 3×1016 ions.cm-2, but changed obviously whcn ion dose was beyond3×1016 ions.cm-2.

Quantum interference in laser-assisted photo-ionization excited by a femtosecond x-ray pulse

The photoelectron energy spectra （PESs） excited by monochromatic femtosecond x-ray pulses in the presence of a femtosecond laser are investigated. APES is composed of a set of separate peaks, showing interesting comb-like structures. These structures result from the quantum interferences between photoelectron wave packets generated at different times. The width and the localization of each peak as well as the number of peaks are determined by all the laser and x-ray parameters. Most of peak heights of the PES are higher than the classical predictions.

Low thermal expansion and broad band photoluminescence of Zr0.1Al1.9Mo2.9V0.1O12

A new material of Zr0.1Al1.9Mo2.9V0.1O12 is synthesized by the traditional solid state synthesis method.The phase transition,coefficient of thermal expansion,and luminescence properties of Zr0.1Al1.9Mo2.9V0.1O12 are explored with Raman spectrometer,dilatometer,and x-ray diffraction(XRD)diffractometer.The results show that the Zr0.1Al1.9Mo2.9V0.1O12 possesses the strong broad-band luminescence characteristics almost in the whole visible region.The sample is crystallized in a monoclinic structure group of P21/a(No.14)crystallized at room temperature(RT).The crystal is changed from monoclinic to orthorhombic structure when the temperature increases to 463 K.The material has very low thermal expansion performance in a wide temperature range.Its excellent low thermal expansion and strong pale green light properties in a wide temperature range suggest its potential applications in light-emitting diode(LED)and other optoelectronic devices.

Wood Moisture Content Measurement by X-Ray Exposure Method

Although quite a numer of papers can be found up to now dealing with the subject of the measurement ofwood density by using the X-ray exposure methods, direet scanning or radiographic photography, the following two aspects,which are very important from both theorctical and engineering application points of view, have not yet been properly handled. One is that the elementary analyses or the experimental measurement on the mass attenuation coefficients were notspecified in regard to spectnun energv distridutions [1]. In this connection, the ambiguities in the specification of the coeffiecients and in turn for thc results among studies arise when only one of the two parameters, namely wave length and applied voltage, of detining the energy spectrum of X-ray is given. The oher is that the relationships between the relative intensity and the sample thickness as well the wood moisture content [2], which are the critical factors for the design and theselection of X-ray apparatus, were not sufficiently examined. In addition, the knowledge of the measurelnent of woodmiosture content by using the direct X-ray scanning method is also almost unavaible now. In the study, the direct X-rayscanning method of measuring wood moisture content was at first investigated theoretically with respect to the relationshipbetween the mass attenuation coefficients of wood (beech, Fagus Sylvatica) and the maximum spectrum energy of X-ray.Secondly, the dependence of the relative intensity on the sample thickness and on the wood moisture content was analysed.The main advantage of the method is on-site nondestructive measuring of wood moisture content in the processes such asdrying, impregnation and unsteady mass diffusion. Specifically for the application in the area of biomechanics, the methodcan also bc used for understanding the water pathway within wood, for example, the water around the knots and the relation between the stress distribution and the local moisture content of wood.

Influence of Sn Low Doping on the Morphological, Structural and Optical Properties of ZnO Films Deposited by Sol Gel Dip-Coating

In this work, Undoped Zinc Oxide (ZnO) and Sndoped Zinc Oxide (ZnO:Sn) films have been deposited by sol-gel dip coating method, where the Sn/Zn atomic ratio was 3% and 5% in the solution. The effects of Sn incorporation on morphological, structural and optical properties of ZnO films were investigated. The Scanning Electron Microscopy (SEM) showed that the morphological surface of the films was affected by Sn low doping. The X-Ray Diffraction (XRD) patterns showed that all films have polycrystalline structures, and the doping incorporation has not lead to substantial changes in the structural characteristics of ZnO films. The crystallite size was calculated using the well-known Scherrer’s formula and found to be in the range of 23 - 40 nm. The measurements from UV-Visible Spectrophotometer (U-Vis) indicated that the highest average optical transmittance in the visible region was related to Undoped ZnO film, then the optical band gap and Urbach energy values of thin films were calculated. The X-Ray Photoelectron Spectroscopy (XPS) has demonstrated that Sn is incorporated in ZnO lattice.

双低剂量技术在双能量头颈部CT血管成像中的应用

目的 探讨双低剂量扫描技术在双能量头颈部CTA扫描中的可行性。方法 前瞻性收集2021年1月~2021年5月间本院102名因头颈部血管疾病行头颈部CTA的患者纳入研究,随机分为CD、DLD两组,CD组行常规剂量扫描,DLD组行双低剂量扫描;分别对两组图像行MIP、VR、 MPR、 CPR、双能量去骨去钙化等后处理,用5分法对两组图像质量进行主观评价,选取颈总动脉起始部、颈内动脉起始部和大脑中动脉M1段测量血管的噪声、SNR、CNR,记录2组患者的x线剂量参数,包括CTDIvol(mGy)和DLP(mGy·cm),计算其有效剂量ED(mSv),亦计算2组患者的碘摄入量I(mg),对结果进行统计学分析。结果 CD组与DLD组的主观图像质量评分均≥3分,均能满足诊断的要求。2名医师对2组图像质量评价的一致性好(Kappa值分别为0.817、0.82 5)。2名医师对2组图像的主观质量评分的差异无统计学意义(Z=-0.572、-0.2 83,均P>0.05)。CD组与DLD组图像各层面血管CT值的差异均无统计学意义(t=-0.05、0.689、0.906,均P<0.05);颈内动脉起始部、大脑中动脉M1段层面血管噪声、SNR、CNR的差异均无统计学意义(t=-0.830~1.842,均P>0.05);颈总动脉起始部层面CD组噪声大于DLD组(t=2.855,P<0.05),SNR、CNR小于DLD组(t=-4.959、-5.041,均P<0.05)。DLD组患者C TDIvol、DLP及ED较CD组分别降低36.9%、35.3%、35.2%(t=186.138、37.753、37.753,均P<0.05)。DLD组患者碘摄入量较CD组降低57.1%(10.5g VS.245g)。结论 双低剂量双能量头颈部CTA扫描技术在不影响图像质量的前提下,降低了患者接受的辐射剂量和对比剂碘摄入量。

基于WPES与MEEMD的船用主机振动研究

为揭示船用长冲程低速柴油机健康状态下的振动特征,采用小波包能量谱(Wavelet Packet Energy Spectrum, WPES)和改进的总体平均经验模态分解(Modified Ensemble Empirical Mode Decomposition, MEEMD)结合的特征提取方法,对典型推进工况下低速机的表面振动信号进行3层小波包分解和重构。通过对能量占比较大的节点采用MEEMD方法进行分解,获得IMF1分量频谱。研究结果表明,在40%以下的较低发动机负荷时,各单次燃烧循环的振动波动较小,振动幅值基本一致。提升至50%以上发动机负荷时,燃烧引起振动波动明显增强。50%工况下,中高频能量占总能量的41.51%,为主要振动源。

基于能谱CT低流速低对比剂在肺动脉CTA图像质量的研究

目的探讨采用能谱CT结合低流速低对比剂在肺动脉CTA中的可行性,并评价其图像质量。方法回顾性分析在安徽省立医院行肺动脉CTA检查的146例患者,随机分成两组,对照组采用常规螺旋CT扫描,观察组用能谱CT联合低对比剂、低流速方法扫描,比较两组图像的客观评分、主观评分及平均碘摄入量。结果两组患者的肺动脉主干、左、右肺动脉干的平均CT值和图像主观评分差异无统计学意义(P>0.05),观察组的背景噪声(SD值)、信噪比(SNR)、对比噪声比(CNR)较对照组略高,但差异无统计学意义(P>0.05),与对照组相比观察组的CT容积剂量指数(CTDI vol)、辐射剂量长度乘积(DLP)和有效辐射(ED)显著降低,差异有统计学意义(P<0.05);观察组有效辐射、平均碘摄入量比对照组分别降低34.82%、48.25%,差异有统计学意义(P<0.05)。结论应用低流速低对比剂结合能谱CT单能量技术,在图像质量满足诊断要求的基础上,显著降低了患者的辐射剂量和碘摄入量。

低计数特征的自然伽马能谱测井数据滤波方法研究

岩石天然放射性强度较弱,自然伽马能谱测井所测得的能谱计数较低,低计数特征使得地层衰变随机误差影响被放大,造成测量能谱质量差、测井曲线统计噪声大的情况。该文通过对比多种能谱滤波结果,使单深度点能谱最大程度还原准确能谱信息;利用曲线形态,针对求解的U、Th、K含量曲线进行深度域的滤波处理,综合从高噪声、低计数的数据中准确提取地层信息;利用中国石油集团测井有限公司的过钻具自然伽马能谱仪器的实测数据验证该方法的有效性。结果表明:对于计数低、谱形差的自然伽马能谱,高斯滤波、卷积滤波效果相对较好,该文提出结合这2种方法的复合滤波可以准确地还原出高保真的能谱形状;深度域的滤波,卡尔曼滤波相对自适应滤波方法有一定优势;依次经过能谱滤波和深度滤波后,结果的准确性和重复性有了大幅提升。该文所介绍的针对低计数特征的自然伽马能谱测井滤波方法,可以有效提高U、Th、K的测量精度。

鄂尔多斯盆地西缘低对比度油层流体判识新方法

随着勘探开发的不断深入,油田勘探开发对象日益复杂化,油水层的低对比度特征愈加突出。受沉积微相、源储配置关系、充注程度等因素影响,低对比度油藏隐蔽性强、油水关系复杂,测井识别评价难度大,解释符合率偏低。因此,亟需建立有效的低对比度油层流体识别技术,提升测井解释精度。以鄂尔多斯盆地西缘环江西部长8储层为例,从研究岩性、物性、水性、含油性等方面入手,深入剖析研究区低对比度油层成因机理,研究认为地层水矿化度差异、束缚水饱和度高、油藏充注程度低是导致环江油田西部长8储层出现低电阻率、低对比度特征的重要因素。在此基础上建立流体敏感因子识别法;并从测井信号能量构成的角度出发,通过构建流体敏感测井曲线,基于小波变换算法,创新研发了多尺度小波能量谱流体识别技术;针对研究区油藏充注程度低,基于相渗实验创新形成了产水率细分油水同层评价方法。以上3种方法均有效提高了研究区低对比度油层流体性质判识能力,在低对比度油层识别方面应用效果显著。

超低剂量CT联合高级建模迭代重建算法在成人肺结核检查中的可行性研究

目的:探讨超低剂量CT能谱纯化技术联合高级建模迭代重建(advanced modeling iterative reconstruction,ADMIRE)算法在成人肺结核检查中的可行性。方法:选取2022年5—12月某院收治的120例继发性肺结核(Ⅲ型)患者,按照随机数字表法将其分为A组、B组、C组、D组,每组30例。A组行常规剂量扫描,管电压为120 kV,管电流为110 mAs,采用滤波反投影重建算法;B组行低剂量扫描,管电压为120 kV,管电流为70 mAs,采用ADMIRE算法(3级);C组行低剂量扫描,管电压为100 kV,管电流为110 mAs,采用ADMIRE算法(3级);D组行超低剂量扫描,管电压为Sn100 kV,管电流为110 mAs,采用ADMIRE算法(3级)。比较4组患者的有效剂量(effective dose,ED)值、图像主观评分及客观评价指标等。采用SPSS 17.0统计学软件对数据进行处理。结果:4组患者的ED值、纵隔窗图像的主观评分、纵隔窗图像的信噪比及对比度噪声比比较,差异有统计学意义(P<0.05)。4组患者的肺窗图像主观评分、肺窗图像的信噪比及对比度噪声比比较,差异无统计学意义(P>0.05)。结论:超低剂量CT能谱纯化技术联合ADMIRE算法能够减少成人肺结核患者检查中的辐射剂量,同时图像质量能够满足临床诊断要求。

Effects of low energy (160 keV) X-ray on microbial inactivation,sprouting inhibition and genetic variation in potato

The effects of low energy X-ray irradiation on microbial inactivation,sprouting inhibition and genetic variation were surveyed.There was an inverse correlation between the exposure dose in range of 0 Gy–5000 Gy and the survival rate of microorganisms.The dose of 1000 Gy seemed to be suitable for inactivation of microorganisms because the respective survival rate is relatively low (0.59%).Dose rate of 13.87 Gy/min was the most appropriate to inactivate the microorganisms,with the survival rate of 0.37%.Applying the irradiation dose of 1000 Gy and dose rate of 13.87 Gy/min,there was a significant sprouting inhibition of irradiated potatoes compared to the control for six months storage.The effect of irradiation dose (100–1200 Gy) and dose rate (8.63–19.62 Gy/min) on genetic variation of the irradiated samples was assessed by DNA fingerprints induced from using three molecular techniques including Random Amplified Polymorphic DNA (RAPD),Start Codon Targeted Polymorphism (SCoT) and CAAT box – derived polymorphism (CBDP).At the irradiation dose of 1000 Gy and dose rate of 13.87 Gy/min,the level of genetic variation was relatively low (4.85%).Thus,this treatment is a suitable condition of irradiation for potato treatment with the purpose of preservation.

某燃气锅炉过热器管失效分析及预防措施

针对某100 t/h燃气蒸汽锅炉在安装调试运行阶段低温过热器管泄漏事故,通过采用渗透检测、力学性能试验、金相分析、扫描电镜及能谱分析等检测方法,对该锅炉低温过热器管泄漏原因进行了试验分析,提出了该类型锅炉在制造或安装阶段质量控制的优化方案,对同类型锅炉制造和安装质量控制及检验检测提供了一定的参考依据。

平滑新能源输出波动的储能优化配置方法

风力、光伏等新能源发电输出功率具有波动性,为减小功率波动对电网的影响,提出平抑功率波动的储能优化配置方法。将频谱分析和低通滤波相结合,根据新能源输出功率频谱分析结果,结合并网功率波动率约束、储能充放电效率及荷电状态(state of charge,SOC),在频率波动范围内确定最佳的一阶低通滤波器的截止频率,得到经滤波和修正的并网联络线功率及储能充放电补偿功率,从而确定满足平滑出力运行控制需求的最优储能额定功率、容量和初始SOC。采用南京地区某屋顶光伏实测数据及波动要求,对该方法进行验证,结果表明采用此方法能以较小储能容量将光伏输出功率波动从27.3%降低到1.62%,且在整个周期内储能不会过充过放。

气体NO/N_2系统等离子体反应NO还原机理研究

首先建立了气体放电等离子体发射光谱测量系统,获得了NO/N2和纯N2气体放电的发射光谱,然后用自洽场分子轨道从头计算法得到了N2基态和激发态分子轨道模型。发现NO/N2气体放电等离子体脱除NO主要是通过包括反应速度非常怏的N+NO→N2+O以及e+N2(A3∑u+)→2N+e和e+N2→N2(A3 ∑u+)+e在内的一系列基元反应进行的,活性N原子是NO还原的基础。