上气道DR管电压与辐射剂量和图像质量的关系

目的 探讨成人上气道DR管电压选择与辐射剂量和图像质量的关系.方法 用聚甲基丙烯酸甲酯( PM MA)模拟成人上气道厚度和对比度细节体模(CDRAD2.O)组合,以不同管电压自动曝光控制系统(AEC)摄影,记录入射体表剂量(ESD)、剂量面积乘积(DAP)和曝光量(mAs),计算体模图像质量因子(IQF值),选定适宜管电压.结果 ESD、DAP、mAs随着管电压升高而下降,IQF值却增大,其间差异有统计学意义(F =45.15、26.41、29.26、56.53,P＜0.05).75 kV以下ESD、DAP、mAs明显增大,75 kV以上逐渐降低,75～80 kV趋于平衡.50～75 kV之间IQF值差异无统计学意义,75～90 kV之间IQF值差异有统计学意义(F=11.35,P＜0.05).不同管电压的正常人体上气道的图像质量无明显差异.结论 成人上气道DR的适宜管电压范围为75～80 kV,用IQF值对照图像质量评分可为临床评价图像质量提供依据.     

直接数字化X线摄影在胸部的应用价值

目的：探讨直接数字化X线摄影（DR）在胸部摄影中的应用价值。材料和方法：回顾性分析我院DR胸片和常规胸片各100例，分别统计一、二、三级片，同时对胸部结构进行评价对比分析。结果：胸部DR能清楚显示病变，尤其是微小病变，其图像质量明显优于常规X线摄片。结论：DR胸部数字化X线摄影弥补了常规X线摄影的不足，具有很大的临床应用价值和广泛的前景。     

200例高千伏胸片非晶硅和非晶硒图像质量对比分析

本文以高千伏(kV)胸部后前位片,对非晶硅数字化摄影(digital radiography,DR)和非晶硒DR的图像质量作对比回顾性分析及综合评价,初步探讨非晶硅和非晶硒两种平板探测器在高kV胸片摄影时的图像质量差异.     

床旁DR与CR胸部摄影质量的对比研究

目的通过床旁数字化X线摄影(digitalradiography,DR)系统与计算机X线摄影(computedradiography,CR)系统胸部摄影图像质量的对比分析,探讨床旁DR摄影的优势。方法随机抽取2010年拍摄的DR床旁X线胸片1000份和既往CR床旁X线胸片1000份进行对比分析。结果床旁DR摄影的应用提供了更加优良的图像质量,明显减少了放射技师的工作量,同时还降低了患者接受的辐射剂量。结论床旁DR胸部摄影比CR胸部摄影有着明显的优势,对手术患者和危重患者的诊治起到了积极作用。     

DR床边胸部摄影辐射剂量优化的实验研究

目的 探讨数字化移动DR床边机在胸部正位摄影中的条件最优化.资料与方法 采用岛津MobileDaRt床旁机分别用固定管电流、增加管电压和固定管电压、增加管电流两种方法对人体胸部模型进行曝光,同时测量距阴极1 m处的辐射剂量,辐射测量仪离地高80 cm.每组获得的图像请2名有经验的放射科医师采用双盲法进行评分.对计数资料进行t检验,计量资料进行卡方检验.结果 固定管电流,管电压从70 kU增加到85 kU,每组得到的图像质量所对应的受试者操作特性曲线(ROC)曲线下的而积(Az值)分别为0.383,0.733,0.675,0.250.固定管电压,管电流从0.5 mAs增加到1.8 mAs,每组得到的图像质量所对应的Az值分别为0.650,0.683,0.817,0.725.kV和mAs分别与图像质量R×C卡方检验P=0.012,P=0.001.结论 管电压和管电流的改变都会影响到辐射剂量,并且两者都与辐射剂量呈正相关.在实际的临床运用中应该选取合理的曝光条件.     

床旁数字X线胸部高千伏摄影在重症监护病房的应用

目的探讨床旁数字化X线摄影（digital radiography,DR）胸部高千伏摄影在重症监护病房（ICU）患者的应用价值。方法在ICU患者床旁DR胸部正位摄影中,把研究对象随机分为对照组和实验组．对照组摄片条件为管电压80kv,曝光量10～16mAs;实验组摄片条件为管电压125kV,曝光量1．8-2．0mAs．评价影像质量及患者辐射剂量。结果经计算实验组甲级片、乙级片百分率均高于对照组,影像质量实验组比对照组好。实验组患者所受辐射剂量明显小于对照组,差异有统计学意义（P〈0．05）。结论在ICU病房中用DR行胸部摄影,采用高千伏技术在提高影像质量,降低曝光量,减少受检者辐射剂量等方面有明显优势。     

X线高千伏摄影胸片质量探讨(附500例分析)

胸部高千伏摄影技术临床应用最广 ,对于肺内广泛病变具有较高的诊断价值 ,笔者重点对高千伏胸片的影像质量进行分析。材料与方法从我院 1999年 3月～ 2 0 0 0年 3月所摄的 40 0 0余张高千伏胸片中随机抽出 5 0 0张 ,作为此次分析的材料。 5 0 0张高千伏胸片全部为正位 (后前位 ) ,男 3 3 5张 ,女 165张 ,患者年龄 15～80岁。同时抽取常规摄影后前位胸片 10 0例作为对照组。摄片机型号 :ＰＨＩＬＩＰＳ Ｍｅｄｉｏ 5 0ｃｐ ,日产富士胶片。自动洗片机型号 :Ｋｏｄａｋ Ｍ 3 5。以每张照片的主要缺点作为统计内容 ,侧重于摄影技术和暗室操作 ,…     

直接数字化摄影在尘肺病检查及诊断中的应用研究

目的：探讨直接数字化摄影（DR）技术在尘肺病检查和诊断方面的应用价值。方法选择来我院欲提交诊断的20世纪60～80年代参加国防施工的复退军人及部分经职业健康查体筛选的企业工人共计811例,同时拍摄高千伏（HkV）胸片及DR胸片,部分加照CT扫描胸片,并对二组胸片进行质量及尘肺病诊断一致性等方面的比较。结果二组胸片的质量对比发现：DR胸片总体质量优于高千伏胸片,尤其DR胸片的一级片率明显高于 HkV胸片,DR胸片的三级片率明显低于HkV胸片,且差异有统计学意义（ P ＜0．05）;DR胸片在图像清晰度及肺部微细结构显示方面较好,两组胸片的诊断结果基本一致,尘肺患者胸片在小阴影形态、总体密集度、分布范围方面无明显差别。结论 DR胸片质量好于HkV胸片,三级片率明显低于HkV胸片;DR摄影可用于尘肺病检查与分期诊断。     

数字X线摄影和计算机X线摄影的应用比较与评价

探讨数字X线摄影(DR)和计算机X线摄影(CR)两大数字化摄影技术的临床应用.材料和方法:用德国Pehamed公司产测试板分别测量DR和CR的空间分辨率,并从100例两者所摄得的正位胸片中,分析图像质量,统计受检者的照射剂量,比较在技术操作、图像质量控制与后处理技术、工作效率、医院效益等方面的优势.结果:DR和CR均提高了图像质量,不同程度减低了被检者所受X线照射量,通过缩短检查和发报告的时间加快了工作效率,带来更高的效益,DR较之CR更具优势.结论:DR与CR相比DR图像质量、后处理功能、工作流程能力、病人吸收剂量均明显优于CR,DR具有更广阔的前景.     

屏胶组合与成人胸片高千伏效应摄影技术分析

目的：研究和评价不同屏胶组合，在不同电压下的摄影成像技术：照片质量；影像特征性表现；肺野内细微结构显示率，并进行千伏效应分析。材料与方法：三种屏胶组合，应用三种电压进行成人胸部X线摄影，运用诊断学及技木学评审观点，经双盲法评审，通过统计学处理。结果：500例胸片肺野内细微结构显示率中，钙屏蓝片100例普通电压为15%；100例准高电压为80%；100例高电压为98％；100例快速辱蓝片准高电压为95％；100例绿屏绿片为100％。经境计学处理P＜0．01，检验有显著意义。结论：1、中速屏蓝片高电压成人胸部X线摄影影像质量，明显优于普通电压及准高电压；2．绿屏绿片高电压成像技术将领先于传统屏胶组合，为传统X线摄影及照片质量开创了一个崭新的技术路线。     

Investigation of beam quality for digital chest radiography with RbBr:Tl(+) photostimulable storage phosphors

Beam quality for digital chest radiography in digital radiography systems (DR systems) with RbBr:Tl(+) photostimulable storage phosphors was investigated. Measurements of overall Wiener spectrum (overall WS) and observer performance experiments by means of Scheffé's method of paired comparisons were performed under the same exposure (5.16x10(-7)C/kg) at the X-ray detector of DR systems (sampling distance: 175 micro m, 2,048x2,048 pixels, 12 bits, look-up table: THX2) with a phantom lung and metacryl plates. Overall WS values were indicated to be inferior at higher tube voltages. All of the overall WS values were greater than those of screen film systems (HGM/UR1:S/F) at radiographic density 0.50, which was considered the density of the mediastinum and the area below the diaphragm (low density area), and at radiographic densities 1.00 and 1.50, considered as lung, WS values of S/F were located between the overall WS values of 80 kV and 100 kV, and 120 kV and 140 kV, respectively. Evaluation of visibility including mediastinum, lung, and total were indicated to be superior at the lower tube voltages. In evaluation of the mediastinum, the base image, which was obtained by 100 kV tube voltage (effective energy: 46.0 kV) in this study, was not significant from 90 kV to 110 kV tube voltages (range, +/-10 kV), and in-lung and total evaluations were not significant from 90 kV to 120 kV (range, -10 kV to +20 kV), and from 80 kV to 120 kV (range, +/-20 kV) tube voltages by 99% confidence interval. In conclusion, optimal beam quality for digital chest radiography with RbBr:Tl(+) photostimulable storage phosphors was considered to be less than 110 kV tube voltage (effective energy, 47.9 keV) in 0.1 mm copper and 3.8 mm aluminum total filtration. In this case, the granularity in low-density areas were inferior to those of S/F systems but nearly equal to the middle and high-density areas of chest images, and exposure dose was 14.3% lower than that of the base image obtained by 100 kV (effective energy, 46.0 keV) tube voltage in this study.     

双能量数字减影胸片对于不同肺野区域内结节性病变的检出差异(ROC分析)

目的　评价双能量数字减影胸片和常规DR胸片对于不同肺野区域内结节性病变的检出差异。方法　 2 0名正常成年志愿者前胸粘贴模拟结节 ,拍摄双能量数字减影正位胸片 ,应用ROC分析比较常规DR胸片与减影后软组织图像的诊断结果。结果　在双上、中肺野 ,软组织图像的曲线下面积大于常规DR胸片 ;在双上肺野、双中肺野外带 2种方法具有显著性差异。结论　双能量数字减影技术对双上肺野及双中肺野外带胸部结节性病变的检出具有优势 ,故应结合减影及常规胸片 ,以助诊断。     

双能量数字减影胸片对肺内小结节检出的意义

目的探讨双能量数字减影胸片对肺内小结节检出的意义。方法27例病理证实恶性肿瘤伴肺内转移的患者,分别行增强CT扫描、双能量数字减影胸片与常规DR胸片。使用柯达质量控制检测仪比较双能量数字减影DR与常规DR胸片的图像质量。再以CT扫描结果为金标准,由2位高年资放射科医师采用双盲法对双能量数字减影胸片与常规DR胸片进行分析,比较两者对肺内转移瘤的检出有无显著差异。结果双能量数字减影DR与常规DR图像在噪声上(均匀度)无差异,但清晰度稍差。双能量数字化减影的胸片对肺内小结节的检出率为91.2%;而常规DR胸片对肺转移瘤的检出率为85.0%,两者之间有显著差异(P<0.05)。结论双能量数字减影技术可减少肺野内骨骼及其它钙化影响,对肺内结节的检出能力高于常规DR胸片。     

X射线胸部摄影曝光剂量与图像质量相关性研究

目的 研究数字化X射线胸部高千伏摄影曝光剂量与图像质量的关系,确定数字化X射线摄影最佳曝光剂量。方法 选择胸部高千伏摄影管电压120 kV,摄影mAs从1 mAs逐档增加至25 mAs,对模拟人体胸部厚度摄影体模与CDRAD 2.0对比度细节体模进行摄影,测量体模表面X射线入射剂量,由5位观察者独立阅读体模影像,比较任意两曝光条件组之间的图像质量因子（IQF）,确定高千伏胸部摄影最佳条件。比较4和10 mAs条件下正常人体胸部摄影图像质量评分。结果 胸部高千伏摄影体模曝光条件从1 mAs增加到25 mAs,体模表面X射线入射剂量从0.067 mGy增加至1.468 mGy。随着X射线入射剂量的增加,影像质量影响因子IQF值不断减小,观察者阅读体模信号的IQF差异有统计学意义（F=31.00,P<0.05）,曝光剂量条件选择在1~4 mAs时所对应的IQF均值差异有统计学意义（F=15.3,P<0.05）,4~10 mAs时所对应的IQF差异无统计学意义,10~25 mAs时所对应的IQF均值差异有统计学意义（F=9.74,P<0.05）。曝光剂量条件选择4和10 mAs所对应的体模表面入射剂量为0.250和0.606 mGy,两种条件下胸部图像质量的综合评分分别为（24.8±1.64）、（25.8±2.05）分,差异无统计学意义。结论 随着数字化X射线摄影剂量的增加所获得图像信息量增加。满足临床诊断的标准人体胸部高千伏数字化X摄影最佳剂量为0.250 mGy左右。     

Subtle pulmonary nodules: detection and identification with storage phosphor radiographs and conventional chest films

To determine the value of digital storage-phosphor radiography (SR) on the detection and identification of subtle lung nodules, postero-anterior (PA) and lateral (LAT) film-screen (FR) chest radiographs were compared with isodose SR images of 45 patients with metastatic malignancies. The SR postprocessing was done with a particular mode previously optimized for routine chest radiography. Pulmonary metastases were found in 34 patients and were proved or excluded by CT (n = 28) or longterm follow-up FR (n = 17). Chest images were divided into four regions for evaluation of image quality, number of lung nodules per region and marked pulmonary structures by receiver-operating characteristics (ROC) analysis (45 patients; 125 nodules; 2810 observations; five readers). Of the nodules selected for an ROC study 82 % were 0.5–1.0 cm in diameter. Overall image quality was rated better for FR concerning lung fields (PA) and mediastinum/hilum (LAT). More lung-field nodules were detected on FR than on SR chest images (P < 0.05). Use of FR was superior to SR in the general identification of nodules (PA chest), especially concerning intermediate (P < 0.01) and subtle abnormalities (P < 0.05), whereas there was no significant difference for LAT chest images. Our results show, that currently FR still has advantages over SR in the detection and identification of subtle lung nodules in routine clinical radiography. Correspondence to: R. Scheck     

Low-voltage digital selenium radiography: detection of simulated interstitial lung disease, nodules, and catheters--a phantom study

PURPOSE: To compare three tube voltages in digital selenium radiography for the detection of simulated interstitial lung disease, nodules, and catheters. MATERIALS AND METHODS: Simulated catheters, nodules, and ground-glass, linear, miliary, and reticular patterns were superimposed over an anthropomorphic chest phantom. Digital selenium radiography was performed with different tube voltages (70, 90, and 150 kVp). Hard-copy images were generated. Detection performance of five radiologists was compared by using receiver operating characteristic (ROC) analysis involving 54,000 observations. RESULTS: The detection of ground-glass, linear, miliary, and reticular patterns over lucent lung and of nodules equal to, smaller than, and larger than 10 mm increased when 70 kVp and/or 90 kVp was used. However, only the reticular pattern was significantly better detected at lower peak voltage (P <.05). Simulated catheters and nodules over the mediastinum showed smaller areas under the ROC curve at lower peak voltage. These results were not statistically significant (P >.05). CONCLUSION: The diagnostic performance of digital selenium radiography at lower peak voltage is at least as good as that at higher peak voltage for interstitial lung disease over lucent lung. Performance is equivalent for nodules and catheters over obscured chest regions at lower peak voltages compared with that at 150 kVp. Our results implicate that the use of high-voltage technique in digital selenium radiography should be reassessed.     

Digital chest radiography with a large-area flat-panel silicon X-ray detector: clinical comparison with conventional radiography

This was a radiologists' preference study to compare a digital chest radiography system that utilizes a large-area silicon flat-panel detector with conventional radiography for visualizing anatomic regions of the chest. Conventional and digital posteroanterior (PA) and lateral chest radiographs were obtained in 115 patients. The PA and lateral image pairs were compared independently by three radiologists rating the overall appearance, 11 anatomic regions in the PA, and 9 in the lateral views. Statistical analysis was performed with the Wilcoxon signed-rank test with Bonferroni-Holm adjustment (p=0.05). For the PA view, the digital system performed significantly better for the overall appearance and for all anatomic regions except for the peripheral pulmonary vasculature and hilum, where no significant difference was found. For the lateral digital images, the regions trachea, costodiaphragmatic recess, and hilum were rated significantly worse. The regions retrosternal and retrocardiac lung were rated significantly better. The other regions and the overall appearance showed no significant differences. The described digital chest radiography system showed statistically superior visualization of anatomic regions for PA and an ambiguous performance for lateral images as compared with conventional radiography. After changing some image processing parameters for the lateral view, this system may be suitable for digitalization of chest radiography.     

Digital slot-scan charge-coupled device radiography versus AMBER and Bucky screen-film radiography for detection of simulated nodules and interstitial disease in a chest phantom

PURPOSE: To evaluate the diagnostic performance of full-field slot-scan charge-coupled device (CCD)-based digital radiography in the detection of simulated chest diseases in clinical conditions versus that of two screen-film techniques: advanced multiple beam equalization radiography (AMBER) and Bucky radiography. MATERIALS AND METHODS: Simulated nodules and interstitial nodular and interstitial linear lesions were attached onto an anthropomorphic chest phantom. One hundred sixty-eight lesions were distributed over 25 configurations. A posteroanterior chest radiograph of each configuration was obtained with each technique. The images were presented to six observers. Each lesion was assigned one of two outcome scores: "detected" or "not detected." False-positive readings were evaluated. Differences between the imaging methods were analyzed by using a semiparametric logistic regression model. RESULTS: For simulated nodules and interstitial linear disease, no statistically significant difference was found in diagnostic performance between CCD digital radiography and AMBER. The detection of simulated interstitial nodular disease was better with CCD digital radiography than with AMBER: Sensitivity was 71% (77 of 108 interstitial nodular lesions) with CCD digital radiography but was 56% (60 of 108 lesions) with AMBER (P =.041). Better results for the detection of all lesion types in the mediastinum were observed with CCD digital radiography than with Bucky screen-film radiography: Sensitivity was 45% (227 of 504 total simulated lesions) with CCD digital radiography but was 24% (119 of 504 lesions) with Bucky radiography (P <.001). There were fewer false-positive observations with CCD digital radiography (35 [5.7%] of 609 observations) than with Bucky radiography (47 [9.5%] of 497 observations; P =.012). CONCLUSION: Differences were in favor of the full-field slot-scan CCD digital radiographic technique. This technique provides a digital alternative to AMBER and Bucky screen-film radiography.     

VolumeRAD容积成像在肺结节诊断中的应用

目的探讨VolumeRAD容积成像检测肺结节的价值。方法39例，男21例，女18例，平均年龄（53．8±9．7）岁。用CT进行随访的肺结节患者进行了额外的PA胸部平片检查和VolumeRAD容积成像。三名胸部x线诊断医师在PACS工作站上独立对胸部平片和VolumeRAD图像进行分析，结节依据清晰度被分为“清晰可见”，“不确定”，和“不可见”，依据大小分为：A组（直径〈5mm），B组（直径5～10mm），C组（直径〉10mm）。胸部CT作为参考标准，结节“清晰可见”为真阳性，计算胸部平片和VolumeRAD成像对肺结节的诊断灵敏度。结果CT上共显示结节247个，胸部平片和VolumeRAD成像对肺结节诊断的灵敏度分别为（69．90±1．30）％和（24．02±1．17）Y00（P〈0．05），在各组间和总数间差别均有统计学意义。结论与PA胸片比较，VolumeRAD容积成像具有提高已知肺小结节检测性能的潜力。     

Dose-image quality study in digital chest radiography using Monte Carlo simulation.

One of the main preoccupations of diagnostic radiology is to guarantee a good image-sparing dose to the patient. In the present study, Monte Carlo simulations, with MCNPX code, coupled with an adult voxel female model (FAX) were performed to investigate how image quality and dose in digital chest radiography vary with tube voltage (80-150 kV) using air-gap technique and a computed radiography system. Calculated quantities were normalized to a fixed value of entrance skin exposure (ESE) of 0.0136 R. The results of the present analysis show that the image quality for chest radiography with imaging plate is improved and the dose reduced at lower tube voltage.