数字X线摄影中原发射线和散射线的实验研究

目的：探索数字X线摄影中散射线对图像质量的影响，确定散射线影响最小、图像边界清晰的窄束X射线的线束直径。方法：在2mm厚的铅板上钻0．8mm-10．0mm不同直径的小孔，获取不同直径的X射线束。以80kV管电压、50mA管电流、15em厚的有机玻璃体模，模拟临床成像条件，获取不同直径的圆形X线束图像，并在相同条件下获取不用铅板的X射线束的图像（开放野）；由ImageJ 1．36b图象处理软件获取沿圆形图像直径方向上的像素值，绘制像素值曲线图，分析X线束图像特征。结果：经2．0mm小孔准直后，散射线对X射线束图像质量的影响几可忽略，可认为X射线束图像全是由原发射线形成的的窄束X射线，图像的像素值与空气间隙大小无关。结论：根据开放野测得的总信号和2．Omm小孔测得的原发射线信号可以计算出散射线的强度，从而将散射线分离出来。     

DR组织均衡技术在低剂量鼻骨侧位X射线摄影中的应用

目的探寻在鼻骨侧位X射线摄影中利用数字化X射线摄影(DR)组织均衡技术获取满足诊断需要的图像并降低患者辐射剂量的研究。方法利用人体模型进行常规的鼻骨侧位摄影,然后固定千伏值,在原有的mAs值上分别降低0.4、0.8、1.2 mAs进行摄片,再将降低剂量的图像采用DR组织均衡技术进行处理,比较不同图像对于满足诊断的需要和患者所接受的辐射剂量。结果常规摄影技术得到的图像需反复调节不同的窗宽、窗位才能显示密度、厚度不同的鼻骨与软组织;降低0.4、0.8 mAs,虽然图像的空间分辨率降低,但是采用DR组织均衡技术可在同一幅图像上清晰显示鼻骨与邻近软组织结构,同时降低患者的辐射剂量;降低1.2 mAs,不但图像的空间分辨率降低,而且无法采用DR组织均衡技术使图像达到满足诊断需要。结论采用DR组织均衡技术不仅能将密度、厚度不同的鼻骨及邻近软组织在同一副图像上清晰显示,而且能够有效降低患者的辐射剂量。     

156例DR全脊柱拼接摄影照片质量分析

目的通过对近期156份数字化射线摄影(DR)所做全脊柱照片质量分析,讨论影响照片质量的因素。方法随机选取开展DR全脊柱摄影以来的156例患者照片,其中男性45例,女性111例;年龄9～75岁,平均年龄42岁。按照包括的部位、图像清晰度、全片密度有无差异、拼接线是否明显、全片各部位是否失真来评价照片质量。结果全部照片中,有1例头颈部与其他部位比例失调,3例全片密度差别太大,2例因拼接点上下影像变形失真而使拼接线明显,不影响诊断,4例拼接点选择错误影像失真,4例因呼吸运动导致拼接错位。结论影响DR全脊柱拼接成像片的原因很多,但合格的照片质量要优于计算机X射线摄影片,完全能满足诊断要求。     

脊柱全景成像技术在脊柱侧弯摄影中的应用

目的探讨脊柱全景成像检查技术在脊柱侧弯摄影中的应用价值。方法采用Slot检查技术46例脊柱侧弯患者(A组),其中男性19例,女性27例;年龄11～18岁,平均年龄15岁。采用数字化X射线摄影(DR)拼接技术58例脊柱侧弯患者(B组),其中男性33例,女性25例;年龄10～19岁,平均年龄16岁。Slot检查技术,通过一次连续几秒曝光获得从颈椎上段至骶尾椎的脊柱全长影像,与行DR拼接技术(通过2次摄影2张X射线照片,经过剪切、重叠拼接成全脊柱片)进行比较。结果A组患者均一次性完成全脊柱摄影检查,颈、胸、腰、骶、尾椎同时在1张X射线照片上清晰显示,整个图像密度均匀,无拼接伪影。B组患者,23例因患者移动导致重拍,16例因照片拼接误差较大导致重拍,其余19例均一次完成检查。所摄X射线照片中,患者颈、胸、腰、骶、尾椎整体影像与图像细节均显示良好,全脊柱图像可见明显的拼接伪影。B组患者中长度拼接误差14例(24.1%),角度拼接误差49例(84.5%),图像后处理放大率不同拼接误差6例(10.3%)。结论采用Slot全脊柱摄影对脊柱侧弯患者进行术前检查,与过去的DR拼接摄影法相比,不但能够清晰地显示脊柱全长影像,同时极大地提高了测量精度,保证了全幅图像密度均匀一致,对脊柱侧弯患者进行术前计划具有重要的临床意义与应用价值。     

CR静脉肾盂造影图像质量与X射线剂量的探讨

目的探讨计算机X射线摄影（CR）在静脉肾盂造影应用中以满足图像诊断质量和X射线曝光参数（kVp、mAs）的优化组合,使X射线剂量控制在最低,降低被检者的有害X射线辐射量。方法对3组不同体型厚度（18cm、22cm、26cm）的被检者,对每组分别以常规摄影条件,增加kVp、降低mAs进行摄影。以kVp与mAs组合图像质量完全满足诊断要求,剂量最低的参数作为最优参考曝光参数。用体模替代3种被检者体型厚度,用同样摄影曝光参数,分别测量体表、体后及有关被检者器官组织的吸收X射线剂量。结果与常规摄影相比,被检者的X射线吸收剂量平均降低了31.97%,面积乘积剂量平均降低了34.57%,有效剂量降低了33.98%。结论在静脉肾盂造影中用CR成像技术与投照参数优化组合,对降低被检者的X射线吸收剂量是行之有效的,为其他投照部位用CR或数字X射线摄影（DR）数字成像参数优化组合研究提供了指导性的方法,有一定的临床应用价值。     

DRX线投照技术与传统X线投照技术的临床应用分析

目的 比较分析传统X线投照技术与DRX线投照技术临床诊断准确率,同时进行简要评价.方法 对近期在我院进行诊疗的30例股骨坏死患者临床资料进行回顾分析,患者入院统一接受传统X线投照检查与DRX线投照检查,对比两种方式检查结果.结果 根据两组检测结果可得,传统X线投照技术检出率为83.33％,DRX线投照技术检出率为96.67％,检出率比较传统X线明显不如DRX线投照技术,且具有统计学差异,P＜0.01.结论 与传统X线投照技术检出率比较来看,DRX线投照技术具有更高的检出率,更利于患者的临床诊断,临床推广使用价值较大.     

腰椎融合后邻近节段影像学评估方法的应用随访

背景：目前多数研究只分析了脊柱融合治疗紧邻融合区域头尾侧节段的术后改变,未对其他紧邻内固定的未作融合节段进行对照研究。 目的：探讨腰椎邻近节段的测量方法,对腰椎后外侧融合后邻近节段的改变进行长期随访影像学评估。 方法：选取尸体骨架6具,以不同投照方式和标本位置行腰椎侧位数字化标准X射线片共计42次(每具标本投照7次)。随访57例腰椎后外侧融合患者,随访时间1.5~4年,拍摄融合前及末次随访时的数字化标准X射线片,所有资料用失真代偿X射线分析法测量椎体间矢状角度、椎间盘高度、椎体间前后移位。 结果与结论：失真代偿X射线分析法测量邻近节段矢状曲度、椎间盘高度、椎体间前后移位时,不同投照方式比较差异均无显著性意义(P > 0.05)。固定节段尾侧椎体间未发现显著的影像学改变,固定节段头侧的多个椎体间矢状角度、椎间盘高度均有明显的改变。提示腰椎后外侧融合后影像学的改变提示固定节段头侧多个椎间盘加速退变。     

GE AMX-4Plus移动X射线机的数字化X射线摄影改造

目的为了提高床旁X射线摄片的图像质量,对现有移动X射线机GEAMX-4Plus进行数字化X射线摄影（DR）改造,由原来影像板（IP）成像再行计算机X射线摄影（CR）扫描获得图像的方式改为DR直接摄片。方法以移动X射线机为基础．配置Pixium3543无线平板系统．设计基于该平板的数字摄影操作平台系统和曝光同步控制系统。结果DR改造后,移动X射线机可以正常使用,性能稳定,图像质量较以前CR模式得到大幅提高,获得临床认可。结论数字化x射线摄影改造既使原有移动X射线机得到充分的利用,也使床旁摄片质量、临床诊断及时性、准确度等方面得到大幅提高。     

优质胸椎DR干式激光图像密度标准研究

影像科进行数字化X射线摄影（digital radiogra-phy,DR）已有10年左右的时间,已有学者对优质胸部、腰椎计算机X射线摄影（computed radiography,CR）和DR干式激光图像密度标准进行了研究[1～4]。但是还没有学者对优质胸椎DR干式激光图像密度标准进行研究。按随机化原则选取100例病人,     

基于模糊最大熵的医学X增强方射线图像边缘法研究

目的：由于医学X射线图像在数字化成像过程中容易受到成像设备中射线散射、电器噪声以及人体组织结构的复杂性等因素的影响,导致数字医学x射线图像的质量不高。因此,针对数字医学X射线图像对比度较差,目标细节信息不明显的特点,研究了一种基于模糊最大熵的图像边缘增强算法。方法：首先将医学X射线图像从灰阶域变换到模糊域。然后通过最大熵准则确定模糊阈值将医学X射线图像分为目标和背景两部分．并分别对其进行图像增强处理．最后再映射回到灰阶域。结果：本文以主动脉造影X射线图像为例,对其分别进行经典模糊边缘增强、反锐化边缘增强和模糊最大熵边缘增强处理,并对处理后图像的相关参数进行定量分析。结论：结果表明基于模糊最大熵算法处理后的图像质量高．边缘细节信息明显增强,且该算法相比其它两种算法具有更好的抗噪性。     

数字X线摄影技术在子宫输卵管造影中的应用

目的通过数字X线摄影（DR）系统在子宫输卵管造影检查中的应用,探讨DR机的优越性。方法分别使用DR和计算机X线摄影（CR）对40例患者进行子宫输卵管造影检查,每组20人。再将所得图像随机分为2组,由2名放射科医师和2名技师采用单独影像观察和比较影像观察的方法,分析CR和DR的影像质量,评价CR和DR摄像系统对图像显示的清晰程度。结果结果显示对DR的影像判断结果评分高于CR;DR具有较好的分辨率和低噪声特性,且通过摄片条件的调整,降低了kV和mA值,可减少患者接受辐射剂量,同时不影响诊断。     

Research on the Influence of X-ray Phase Contrast Imaging Parameters with Micro-focus Source

X-ray in-line phase contrast imaging enables weakly to absorb specimens to be imaged successfully with high resolution and definition. In this paper we use computer simulation method to analyze how each parameter influences the quality of the image. It can avoid wasting unnecessary time and materials in the course of experiment to get ideal images.     

Cephalometry with a video display computer

A new technique to develop cephalometric analyses for orthodontic problems is illustrated. A digital analyzer of images is employed in our laboratory, and this allows us to get the X-ray picture digitized and displayed on both a black and white and a colour TV screen. All the cephalometric points are selected by an operator who watches a coloured cross which can be moved on the colour TV screen by means of a keyboard. A suitable software was developed to calculate linear and angular measurements. The cephalometric coloured lines appear at the top of the X-ray image and the data are displayed on a monitor, from which a print-out is obtained. Such a technique has some advantages: the X-ray image can be processed before the cephalometric analysis to enhance details, thus making the analysis more accurate; the cephalometric lines can be seen on the X-ray image displayed on the colour TV screen and can be photographed or stored on floppy or rigid disc.     

影响DR图像质量因素分析

目的研究影响DR图像质量因素和规避。方法通过DR成像系统成像后,经工作站后处理,调整至最佳传至激光相机打片。选取600幅照片,其中男性326例,女性274例;年龄2天～78岁,平均年龄45岁。照片所摄部位以胸片、脊柱片、四肢骨和关节片为主,通过X射线评片标准,对其质量进行评价,探讨影响成像质量因素。结果甲级片498张,非甲级片102张。通过着重对非甲级片分析,影响DR图像质量因素如下。①技术人员的操作技能和业务技术水平。此原因所致68张,占66%。②摄片技术参数。此原因所致23张,占23%。③机器性能。此原因所致3张,占3%。④图像后处理技术。此原因所致6张,占6%。⑤激光相机。此原因所致2张,占2%。结论影响DR照片质量因素很多,技术人员的操作技能和水平是其主要因素。应用DR设备过程中,只有不断提高技术人员的综合素质水平,规范操作和不断总结使用经验,增强对设备原理的学习,探索更多临床经验,才能得到质量更佳图像照片。     

Telemedicine screening of diabetic retinopathy using a hand-held fundus camera.

The objective was to evaluate digital images of the retina from a handheld fundus camera (Nidek NM-100) for suitability in telemedicine screening of diabetic retinopathy. A handheld fundus camera (Nidek) and a standard fundus camera (Zeiss) were used to photograph 49 eyes from 25 consecutive patients attending our diabetic clinic. One patient had cataracts, making it impossible to get a quality image of one of the eyes (retina). The Nidek images were digitized, compressed, and stored in a Fujix DF-10M digitizer supplied with the camera. The digital images and the photographs were presented separately in a random order to three ophthalmologists. The quality of the images was ranked as good, acceptable or unacceptable for diabetic retinopathy diagnosis. The images were also evaluated for the presence of microaneurysms, blot hemorrhages, exudates, fibrous tissue, previous photocoagulation, and new vessel formation. kappa Values were computed for agreement between the photographs and digital images. Overall agreement between the photographs and digital images was poor (kappa < 0.30). On average, only 24% of the digital images were graded as being good quality and 56% as having an acceptable quality. However, 93% of the photographs were graded as good-quality images for diagnosis. The results indicate that the digital images from the handheld fundus camera may not be suitable for diagnosis of diabetic retinopathy. The images shown on the liquid crystal display (LCD) screen of the camera were of good quality. However, the images produced by the digitizer (Fujix DF-10M) attached to the camera were not as good as the images shown on the LCD screen. A better digitizing system may produce better quality images from the Nidek camera.     

Digital chest imaging using a 57-cm image intensifier: A receiver-operating characteristic study of user performance

Chest radiography provides one of the great challenges to digital diagnostic imaging because of (1) the relatively large size of the chest field, (2) the contrast range required to resolve subtle pathological changes in soft tissue density, and (3) the high degree of spatial resolution required to discriminate pathological detail. The field size problem was resolved by using a 57-cm image intensifier whose video output of the chest could be digitized. The issue of contrast resolution was addressed in a recently completed receiver-operating characteristic study of the detectability of low-contrast densities in a humanoid chest phantom. The latter indicated that, despite the smaller size of the digital image, they were adequate for resolving clinically significant soft-tissue densities. The question of spatial resolution in digital diagnostic images is addressed in the study presented. A set of 41 clinical cases were selected to provide the typical range of diagnostic type experienced in routine diagnostic radiology. The images were each presented as conventional film, digital laser-printer, and digital video images. The results of an ROC analysis of five readers' performance in each of the viewing modes is presented.     

拼接法全脊柱摄影外固定架的设计和自制

目的为部分有全脊柱摄影需求、但无该功能设备的医院介绍一种简易全脊柱摄影外固定架的自制,帮助其低成本实现全脊柱（长骨）摄影功能。方法采用不锈钢钢管、有机玻璃、玻纤板、报废X射线机的床面板等、带锁止的万向轮等,底座长宽各为60cm、高8cm的扁盒子,放填充物,提高稳定性。底座下面四个角安装带锁止万向轮。在底座上面四角上竖固定外径为40 mm的不锈钢管,高度约1.8 m,顶端焊成正方形,其中2根用于固定背板,另外2根为被检者上臂平前伸时手握。选择236例摄全脊柱片患者,其中男性158例,女性78例,年龄7～76岁。使用该固定架,进行数字X射线摄影（DR）。结果利用该外固定架,已摄影200余例,成像质量优于计算机X线摄影单次曝光拼接法。其中3例因患者年龄太大有少许左右移动错位外,其他全部合格,优秀率73%;曝光量设定错误,全片存在密度差异4例,但不影响诊断。结论对无全脊柱摄影功能的DR来说,只要有含拼接功能的工作站,利用自制外固定架,也能得到优质的全脊柱图像。     

Diagnostic accuracy and image quality using a digital camera for teledermatology.

OBJECTIVE: The study was designed to evaluate the effectiveness of digital photography for dermatologic diagnoses and compare it with in-person diagnoses. MATERIALS AND METHODS: Patients referred for specialty consultations (n = 308) were recruited from a university dermatology clinic. Patients were examined in-person by one of three board-certified dermatologists who provided clinical diagnoses. Digital photos were obtained on all patients and were evaluated as computer images by a panel of dermatologists. RESULTS: There was 83% concordance between in-person versus digital photo diagnoses. Intradermatologist concordance averaged 84%, and interdermatologist concordance averaged 81%. Decision confidence was rated as "very definite" to "definite" 62% of the time. Concordance with biopsy results was achieved in 76% of the cases. Image sharpness and color quality were rated "good" to "excellent" 83% and 93% of the time, respectively. CONCLUSION: Digital photography for store-and-forward teledermatology produces high-quality images and diagnostic concordance rates that compare favorably with in-person clinical diagnoses.     

Integrated model for estimating phosphor signal and noise transfer characteristics on medical images: application to CdPO<Subscript>3</Subscript>Cl:Mn phosphor screens

An integrated model describing the signal and noise transfer characteristics of the objective image quality and information content in phosphor-produced images is presented. In the context of this model, important imaging parameters, namely optical gain, modulation transfer function, noise transfer function, detective quantum efficiency and information capacity were experimentally evaluated using seven laboratory-prepared CdPO₃Cl:Mn test phosphor screens of varying coating thickness. This phosphor has been previously shown to exhibit high spectral compatibility properties with the films and optical sensors used in digital imaging systems. Experiments were performed using 50–120 kVp X-rays produced by a medical X-ray unit. Results showed that, for thick screens, optical gain attained peak values close to 200 optical photons per incident X-ray at 50 kVp. The noise transfer function was higher than the modulation transfer function. For the thin screen of 21 mgcm⁻², the modulation transfer function was 0.25 at 100 line pairs mm⁻¹, and the corresponding noise transfer function was 0.4. The detection quantum efficiency peak value was 0.22 at 50 kVp. These values are within acceptable performance limits, and, given the phosphor material's high spectral compatibility and medium temporal response, CdPO₃Cl:Mn could be considered for use in X-ray detectors of static radiography imaging.