Functional Confirmation Using a Medical X-Ray System of a Semiconductor Survey Meter

In recent years, semiconductor survey meters have been developed and are in increasing demand worldwide. This study determined if it is possible to use the X-ray system installed in each medical facility to calculate the time constant of a semiconductor survey meter and confirm the meter’s function. An additional filter was attached to the medical X-ray system to satisfy the standards of N-60 to N-120, more copper plates were added as needed, and the first and second half-value layers were calculated to enable comparisons of the facility’s X-ray system quality with the N-60 to N-120 quality values. Next, we used a medical X-ray system to measure the leakage dose and calculate the time constant of the survey meter. The functionality of the meter was then checked and compared with the energy characteristics of the meter. The experimental results showed that it was possible to use a medical X-ray system to reproduce the N-60 to N-120 radiation quality values and to calculate the time constant from the measured results, assuming actual leakage dosimetry for that radiation quality. We also found that the calibration factor was equivalent to that of the energy characteristics of the survey meter.

Metal-Halide Perovskite Submicrometer-Thick Films for Ultra-Stable Self-Powered Direct X-Ray Detectors

Metal-halide perovskites are revolutionizing the world of X-ray detectors,due to the development of sensitive,fast,and cost-effective devices.Self-powered operation,ensuring portability and low power consumption,has also been recently demonstrated in both bulk materials and thin films.However,the signal stability and repeatability under continuous X-ray exposure has only been tested up to a few hours,often reporting degradation of the detection performance.Here it is shown that self-powered direct X-ray detectors,fabricated starting from a FAPbBr_(3)submicrometer-thick film deposition onto a mesoporous TiO_(2)scaffold,can withstand a 26-day uninterrupted X-ray exposure with negligible signal loss,demonstrating ultra-high operational stability and excellent repeatability.No structural modification is observed after irradiation with a total ionizing dose of almost 200 Gy,revealing an unexpectedly high radiation hardness for a metal-halide perovskite thin film.In addition,trap-assisted photoconductive gain enabled the device to achieve a record bulk sensitivity of 7.28 C Gy^(−1)cm^(−3)at 0 V,an unprecedented value in the field of thin-film-based photoconductors and photodiodes for“hard”X-rays.Finally,prototypal validation under the X-ray beam produced by a medical linear accelerator for cancer treatment is also introduced.

Efficient Deep-Learning-Based Autoencoder Denoising Approach for Medical Image Diagnosis

Effective medical diagnosis is dramatically expensive,especially in third-world countries.One of the common diseases is pneumonia,and because of the remarkable similarity between its types and the limited number of medical images for recent diseases related to pneumonia,themedical diagnosis of these diseases is a significant challenge.Hence,transfer learning represents a promising solution in transferring knowledge from generic tasks to specific tasks.Unfortunately,experimentation and utilization of different models of transfer learning do not achieve satisfactory results.In this study,we suggest the implementation of an automatic detectionmodel,namelyCADTra,to efficiently diagnose pneumonia-related diseases.This model is based on classification,denoising autoencoder,and transfer learning.Firstly,pre-processing is employed to prepare the medical images.It depends on an autoencoder denoising(AD)algorithm with a modified loss function depending on a Gaussian distribution for decoder output to maximize the chances for recovering inputs and clearly demonstrate their features,in order to improve the diagnosis process.Then,classification is performed using a transfer learning model and a four-layer convolution neural network(FCNN)to detect pneumonia.The proposed model supports binary classification of chest computed tomography(CT)images and multi-class classification of chest X-ray images.Finally,a comparative study is introduced for the classification performance with and without the denoising process.The proposed model achieves precisions of 98%and 99%for binary classification and multi-class classification,respectively,with the different ratios for training and testing.To demonstrate the efficiency and superiority of the proposed CADTra model,it is compared with some recent state-of-the-art CNN models.The achieved outcomes prove that the suggested model can help radiologists to detect pneumonia-related diseases and improve the diagnostic efficiency compared to the existing diagnosis models.

Neutronic analysis of ITER radial x-ray camera

The radial x-ray camera(RXC) is designed to measure the poloidal profile of plasma x-ray emission with high spatial and temporal resolution. The RXC diagnostic system consists of internal camera module and external camera module that view the core region and outer region through the vertical slots of the diagnostic first wall and diagnostics shield module of the equatorial port plug. To ensure the normal performance of the silicon photodiode array detectors of the cameras in the hard neutron irradiation environment in ITER tokamak, it is necessary to calculate neutron flux, radiation damage and the nuclear heating of the silicon photodiode array detectors and simulate the radiation maps of the range of RXC. This work estimated the nuclear environment of RXC based on Monte Carlo N-particle transport code, plasma scenarios of ITER tokamak and the RXC-integrated ITER CLITE model. The neutron flux of silicon photodiode array detectors and the lifetime of the silicon photodiode detector in the camera were calculated. The neutronic analysis results show that the shielding design has achieved the effect as expected and is able to guarantee the normal work of the detector during the ITER deuterium–deuterium phase without replacement, three detectors of the external camera can be operated during the whole deuterium–tritium phase without replacement.

Spatial resolution and image processing for pinhole camera-based X-ray fluorescence imaging: a simulation study

Spatial resolution and image-processing methods for full-field X-ray fluorescence(FF-XRF)imaging using X-ray pinhole cameras were studied using Geant4simulations with different geometries and algorithms for image reconstruction.The main objectives were:(1)calculating the quantum efficiency curves of specific cameras,(2)studying the relationships between the spatial resolution and the pinhole diameter,magnification,and camera binning value,and(3)comparing image-processing methods for pinhole camera systems.Several results were obtained using a point and plane source as the X-ray fluorescence emitter and an array of 100×100 silicon pixel detectors as the X-ray camera.The quantum efficiency of a back-illuminated deep depletion(BI-DD)structure was above 30%for the XRF energies in the 0.8–9 keV range,with the maximum of 93.7%at 4 keV.The best spatial resolution of the pinhole camera was 24.7μm and 31.3 lp/mm when measured using the profile function of the point source,with the diameter of 20μm,magnification of 3.16,and camera bin of 1.A blind deconvolution algorithm with Gaussian filtering performed better than the Wiener filter and Richardson iterative methods on FF-XRF images,with the signal-to-noise ratio of 7.81 dB and improved signalto-noise ratio of 7.24 dB at the diameter of 120μm,magnification of 1.0,and camera bin of 1.

An Assessment of Both Patients and Medical Staff Awareness of the Risks of Ionizing Radiation from CT Scan in Cameroon

Objectives: To assess the patients and health personnel’s level of awareness on risks related to ionizing radiation during CT scan. Materials and methods: Three questionnaires were addressed to patients, prescribing physicians, and the medical imaging staff for three hospitals respectively. This permitted us to assess their knowledge on the benefits and risks of the required medical exam, based on the dangers of being exposed to X-rays, especially induced-radiation cancer following the amount of X-rays received during a CT scan and the possibility of not receiving radiation as tools of diagnosis. Results: 150 patients, 84 referring doctors of CT scan tests and 60 medical imaging personnel were retained. For patients, only 7.1% received information on the benefits and risks of their exams, and 34.4% believed that x-rays were harmful to their health. For the prescribers, 46.7% took into account the benefits/risk ratio before prescribing a test and only 16.7% of the referring doctors have informed the patient of the risks related to X-ray. 90% of the medical imaging staff ensures that the required test is justified, and 50% informed the patient on the risks associated with their radiation exposure, and the increased risk of developing cancer. 65% of the imaging staff could not estimate the dose that the patient will receive during the medical test. 25% mentioned the dose received during the acquisition in the patient’s exam report. Conclusion: This study confirms that the referring doctors, the patients, and the radiologists have a low knowledge concerning the risks associated with radiation exposure during a CT scan assessment. We will therefore say that patients and prescribers are not aware of the doses of radiation on CT and their possible risks, even though there is a risk of developing cancer.

Interest of Systematic Chest Radiography during Periodic Medical Visits in Workers

Background: Systematic chest X-ray is the most prescribed examination by occupational physicians during periodic medical check-ups in our context, unlike in most countries where this practice has been discontinued. Objective: The objective was to determine the diagnostic yield and cost-effectiveness of chest radiography during periodic medical check-ups of workers in Ngaoundere. Materials and Methods: A cross-sectional and descriptive study was carried out in Ngaoundere Regional Hospital from January to December 2018, concerning all persons coming to perform a systematic chest X-ray in the context of the periodic medical check-up having been consented to participate in the study. Posteroanterior (PA) chest radiographs were obtained from all workers during this periodic medical check-up. The variables studied were: age, sex, clinical manifestations, antecedents, job type, cost, and chest X-ray results. Statistical analysis was performed using the Sphinx Plus2-Lexica-V5 Edition software. Results: 753 workers were selected for this study, of whom 88.04% were men and 11.96% were women, a sex ratio H/F is of 7.4, the average age was 39 ± 7.89 years with extremes of 24 and 56 years, the most frequent job type was the administration (38.37%), the storekeepers (17.92) and the drivers (15.27%), most of them were asymptomatic (97.47%), some had cough (2.52%), chest pain (2.12%), dyspnea (0.26%) and fever (0.13%). History was dominated by lung infection (2.39%), pleurisy (1.06%) and tuberculosis (0.79%). 7.43% of workers occasionally smoked tobacco and consumed alcohol. 41 cases of pathologies (5.44%) were found on the chest X-ray, including 1 case (0.13%) of evolutionary pathology, 40 cases (5.31%) of sequelae pathologies. When the results of the chest X-ray are compared with the clinical signs and the pathological history of the workers, it is found that the only case with evolutionary abnormalities on the chest X-ray showed clinical signs and that the other cases with sequelae abnormalities had either clinical signs or antecedents related to these abnormalities. The cost of a chest X-ray at the time of our study was 5,000 FCFA ($8.59), for a total of 3,765,000 FCFA ($6473.74) for all the X-rays performed. Conclusion: In view of the low rate of abnormalities on the chest X-ray and the sequelae nature of the pathologies, it can be said that the routine X-ray of the chest during the periodic medical check-ups has a low diagnostic yield and a low cost-effectiveness ratio and is not profitable. It should be non-systematic and case-by-case based on the clinical context and background of workers.

Ultrafast two-dimensional x-ray imager with temporal fiducial pulses for laser-produced plasmas

It is challenging to make an ultrafast diagnosis of the temporal evolution of small and short-lived plasma in two dimensions. To overcome this difficulty, we have developed a well-timed diagnostic utilizing an x-ray streak camera equipped with a row of multi-pinhole arrays. By processing multiple sets of one-dimensional streaked image data acquired from various pinholes, we are capable of reconstructing high-resolution two-dimensional images with a temporal resolution of 38 ps and a spatial resolution of 18 μm. The temporal fiducial pulses accessed from external sources can advance the precise timing and accurately determine the arrival time of the laser. Moreover, it can correct the nonlinear sweeping speed of the streak camera. The effectiveness of this diagnostic has been successfully verified at the Shenguang-II laser facility,providing an indispensable tool for observing complex physical phenomena, such as the implosion process of laser-fusion experiments.

基于魏尔斯特拉斯逼近定理的对医用内窥镜摄像系统信噪比插值方式的研究

YY/T 1587-2018《医用内窥镜电子内窥镜》与YY/T 1603-2018《医用内窥镜内窥镜供给装置摄像系统》信噪比测试方法相同,是采用线性插值的方法,找出Y值在0.707的信噪比。本文基于魏尔斯特拉斯逼近定理的多项式拟合方法,对信噪比插值进行分析,并与分段线性插值的结果进行对比和讨论,对测试条件提出补充性建议。

Covid-19 Detection from Chest X-Ray Images Using Advanced Deep Learning Techniques

Like the Covid-19 pandemic,smallpox virus infection broke out in the last century,wherein 500 million deaths were reported along with enormous economic loss.But unlike smallpox,the Covid-19 recorded a low exponential infection rate and mortality rate due to advancement inmedical aid and diagnostics.Data analytics,machine learning,and automation techniques can help in early diagnostics and supporting treatments of many reported patients.This paper proposes a robust and efficient methodology for the early detection of COVID-19 from Chest X-Ray scans utilizing enhanced deep learning techniques.Our study suggests that using the Prediction and Deconvolutional Modules in combination with the SSD architecture can improve the performance of the model trained at this task.We used a publicly open CXR image dataset and implemented the detectionmodelwith task-specific pre-processing and near 80:20 split.This achieved a competitive specificity of 0.9474 and a sensibility/accuracy of 0.9597,which shall help better decision-making for various aspects of identification and treat the infection.

Design of a control system with high stability for a streak camera using isolated ADC

The streak camera is an ultra-fast diagnostic instrument with high sensitivity, and a high temporal and spatial resolution. It is primarily employed in various scientific research, such as inertial confinement fusion(ICF),synchrotron light sources, and electron–positron colliders.An automatic control system for an X-ray streak camera is presented in this paper. The output terminal of an analogto-digital converter was isolated from its input terminal, to reduce interference from high-voltage electrodes. Compared with traditional methods, this scheme also improved the internal electromagnetic interface immunity. Therefore,the system stability was enhanced. With this optimized control system, some characterizations of the streak camera were measured. Static and dynamic spatial resolutions of 25 and 20 lp/mm(CTF = 20%), respectively, were obtained. In addition, a dynamic range of 552:1 and a temporal resolution of 7.3 ps were achieved. The results confirmed that these characterizations are sufficient for the specifications derived from the diagnostic requirements of ICF.

A rapid and convenient experimental method of absolutely calibrating transmission of x-ray flat-response filter

We develop a rapid and convenient experimental method of absolutely calibrating the transmission of an x-ray flatresponse filter. The calibration experiment is performed on a small laser-target facility, and a set of high resolution holographic flat-field grating spectrometers is used as a discrimination system of the laser-produced x-ray source. Given that the holographic flat-field grating has a relatively large width, the grating is divided into two regions for use in that direction,where one region has the filter added and the other region does not. The filter transmission is determined by dividing the x-ray signal counts detected when the filter is in the line of sight by those detected when the filter is out of the line of sight.We find that the calibration results of this experiment agree with the calibration results using a synchrotron radiation source,as well as simulation results. Our method is not only highly reliable but also rapid and convenient.

脉冲X射线源的获取及门控成像

介绍了带门控的MCP像增强器及条纹相机对激光驱动产生的脉冲硬X射线进行探测的方法 该方法可以减少X射线的散射 ,使图像对比度有较大的改善 ,从而能够大大降低人体对X射线的吸收剂量 。

数码相机在外科学实验课教学中的应用

数码相机因其具有简易、方便、快捷、廉价等优点，在医学教学中得到广泛应用。文章介绍了在外科学实验课教学过程中，应用数码相机记录学生操作过程，及时纠正学生错误，并加深其对规范操作认识和理解的一些做法和认识。

高品质数码相机在医学资源库建设中的运用

通过Nikon D100数码相机在医学资源库建设中的运用，介绍了其特性和操作技巧，指出具有一定品质的数码相机是发展医学摄影不可缺少的基本设备。

搭载摄像功能的数码单反相机在临床医学教学中的应用

目的:探讨兼具视频短片拍摄功能的数码单反相机的使用以及动静态影像在临床医疗、诊断以及医学教学中的应用。方法:选择搭载具备摄像功能的高品质数码单反相机如佳能EOS 5DMarkⅡ或EOS 550D等,应用于临床带教的病例及标本等医学影像的拍摄,并针对临床医学摄影的特点辅之相应的基本操作的指导。结果:相对普及型便携式数码相机,搭载具备摄像功能的数码单反相机除了可以拍摄静止医学图像外,还能够拍摄动态的较高质量的短片视频,用以制作医学教学多媒体课件、培训教材或构建网络化的图文工作站等。结论:搭载摄像功能的数码单反相机的应用,提高了临床医师以及带教实习医学生们记录临床病例资料的灵活性以及多样性,丰富了医学影像资料的采录收集,在临床教学中是一个轻便易携带且具备多功能。

纸质病历扫描拍照存档系统的研发与应用

目的:研发纸质病历扫描拍照存档系统,解决纸质病历的存储检索和保护问题。方法:将纸质病历通过扫描拍照,转换为PDF文件,存储到Web服务器,存储路径与医院信息系统中的患者ID号、住院次相联系,以方便检索。结果:该系统设计成本低,操作简便,检索速度快,安全性高。结论:纸质病历扫描拍照存档系统与医院信息系统融为一体,能满足纸质病历电子化的需要,其设计方案也适合于其他纸质档案的电子化。

基于CUDA的2D-3D配准技术的研究

Nvidia从GeForce8系列开始,在显卡上推出统一计算设备框架技术,使GPU的通用计算(GPGPU)从图形硬件流水线和高级绘制语言中解放出来,开发人员无须掌握图形学编程方法即可在单任务多数据模式(SIMD)下完成高性能并行计算。在医学图像分析中,图像配准通常是一个耗时的过程,不利于临床应用,为了加速医学图像的2D-3D配准过程,研究了CUDA的设计思想和编程方式,提出了一种基于CUDA并行编程模型的加速配准新技术,在构建的虚拟X线摄像系统下,采用并行计算的方式快速生成高质量DRR图像,以对应像素的灰度值残差作为相似性测度,使用Powell优化方法寻找最优变换。实验结果表明,该技术既很好地保持了配准精度,同时又大大提高了配准速度,加速比达到了十几甚至几十倍。

学习风格特征对腹腔镜扶镜技能训练的影响

目的分析医学生的学习风格特征,探讨不同的学习风格特征对腹腔镜扶镜助手技能训练的影响。方法在腹腔镜扶镜助手扶镜技能训练前采用Kolb学习风格量表于2020年9月至12月对哈尔滨医科大学附属第四医院60名实习医生和40名专硕研究生学习风格特征进行评估;然后分析比较实习医生和专硕研究生学习风格特征的差异,以及不同学习风格特征对腹腔镜扶镜技能训练效果的影响。结果实习医生和专硕研究生学习风格特征差异有统计学意义(P<0.001)。实习生群体中以发散型学习风格为主,研究生群体中以聚合型学习风格为主。学习风格特征对腹腔镜扶镜技能效果有显著影响。实习医生和专硕研究生聚合型学习风格受试者在扶镜技能训练中,视野居中、水平位、最佳视野每个周期平均失误数均明显少于发散、同化和调节型学习风格的受试者。结论医学生中不同学习群体有着不同的学习风格特征。在腹腔镜扶镜技能训练中学习风格特征对训练效果有显著影响。医学教育中应该充分兼顾不同学习风格特征的特点,充分发挥学生学习风格优势。

糖尿病性视网膜病变筛查系统远程操控模块设计与实现

糖尿病性视网膜病变是患者致盲的主要疾病之一,定期的视网膜病变筛查是及时发现病变并治疗的唯一有效方法,而糖尿病性视网膜病变的远程筛查则有助于提高患者的筛查依从性。为此,本文对远程糖尿病性视网膜病变筛查系统进行分析,并重点提出系统远程操控模块的设计方案。系统远程操控模块由串口通信模块、操控平台及上位机通信程序3部分组成,实现了对眼底照相机的远程操控。通过测试,本方案所构建的远程操控模块具有结构简单,易安装且通用性较好等特点。