数字化乳腺X线摄影的图像质量分析

目的 探讨影响数字化乳腺X线摄影图像质量的各种因素,以提高乳腺X线摄影技术在影像诊断中的价值.方法 随机抽取2006-10-12间200例经数字化乳腺X线摄影的资料,评价摄影体位、投照技术、机械设备等因素对图像各方面质量的影响.结果 数字化乳腺X线摄影的一级片93.5%(187/200),二级片4.5%(9/200),三级片2%(4/200).在二级片、三级片中,摄影体位不标准4例(2%),压迫不完全2例(1%),异物伪影1例(0.5%),被检查者身体伪影2例(1%),影像板伪影2例(1%),设备校正不良1例(0.5%)以及照片保存不当1例(0.5%).结论 在数字化乳腺X线摄影中,医技人员的投照及操作技术是提高图像质量的关键,被检者和机械设备等是相关因素.     

计算机X线摄影与屏片系统摄影对比分析

目的:评价计算机X线摄影(CR)的应用价值。方法:抽取我院CR照片和常规X线摄影照片各1200 例,由2位主管技师和1位副主任技师对照片进行分析,统计出甲、乙、丙及废片率。并对乙、丙级片及废片产生的 原因进行了分析。结果:①照片影像质量:CR照片甲级片率51.6%,乙级片率35.5%,丙级片率12.2%,废片率 0.7%。常规X线摄影照片甲级片率40.6%,乙级片率42.5%,丙级片率15.2%,废片率1.7%。②摄影条件:数字 比模拟摄影电压高1～5kV,曝光量高20%左右。结论:CR摄影影像质量好于模拟摄影(即甲级片率高,废片率 小),可为临床提供可靠诊断。但曝光条件比屏 片系统高,增加了病人的X线接受剂量。     

新生儿床旁计算机X线摄影胸片图像质量的影响因素评价

目的 评价新生儿床旁计算机X线摄影(computed radiography,CR)胸片图像质量及其影响因素.方法 回顾性分析我院新生儿床旁胸片103例,由2位医师分别在PACS工作站上进行图像质量评级,并且分析影响摄片质量的因素.结果 在参评的胸部床旁摄影片中,曝光条件合适的,即lgM值在1.8～2.2区间的有73份(占70.9％),两位观察者之间的评级一致性为优(Kappa值=0.93),其间两医师所评甲片率分别为36.9％和32.0％,废片率均为0.其中,影像噪声、体位不正、对比度差及异物伪影等因素为影响摄片质量的主要因素,观察者之间的一致性为优(Kappa值=0.87).结论 新生儿床旁CR胸片质量的影响因素是可控的,通过仔细的操作及后处理可获得高质量的图像.     

直接数字X线摄影技术在小儿胸部摄影中的应用

目的: 探讨直接数字X线摄影技术在小儿胸部摄影中的应用.材料和方法: 回顾性分析我院小儿DR胸片和常规胸片各500张,分别统计甲、乙、丙级片及废片,同时对显示胸部结构进行评价,并进行统计学处理.结果: (1)DR胸片: 甲级片51%、乙级片38%、丙级片10%、废片1%;(2)常规胸片: 甲级片42.4%、乙级片45%、丙级片11%、废片1.6%;(3)DR胸片可根据临床要求经不同后处理技术显示胸部各种结构.结论: 小儿DR胸片质量优于小儿常规胸片.     

儿童胸部DR摄片图像质量的影响因素

目的 探索数字DR系统对儿童胸部摄片过程中摄影参数的合理选择与影像质量的关系.方法 选择600例儿童胸部影像进行质量分析,并参照"三甲"医院评定甲、乙、丙片的质量标准进行图像质量评定.结果 照片中甲级片达531张(88.5%),乙级片有62张(10.3%),丙级片7张(1.2%).其中非甲级片原因中以曝光参数、剪裁区域选择不当所占比例最高.结论 为提高数字影像质量,需准确调节胸部数字化摄影各技术参数.     

数字化牙片X线摄影技术及其临床应用

目的 :研究数字化牙片X线摄影技术及其临床应用价值。方法 :采用SIRONA数字化牙片机设备 ,对 2 0 0例患者的 2 5 6颗牙齿行根尖片拍摄。结果 :与根尖片传统摄影比较 ,投照时垂直角度要不同程度加大 ,曝光时间缩短 87%～95 %。质量分级 :甲级片 2 2 9张 ,乙级片 19张 ,丙级片 8张。结论 :数字化牙片X线摄影技术具有传统根尖片摄影技术所不具备的优越性 ,在口腔临床及科研工作方面有良好的应用前景。     

CR系统在乳腺摄影中的应用分析

目的:评价CR系统在乳腺摄影中的应用价值。方法:抽取我院CR乳腺照片和传统钼靶X线照片各800张进行分析,统计出甲、乙、丙级片及废片率;统计CR片及传统屏-片乳腺癌的诊断正确率。结果:①照片影像质量:CR照片甲级片率67%,乙级片率26%,丙级片率7%,废片率0.25%。传统屏-片甲级片率36%,乙级片率50%,丙级片率11%,废片率2.5%。②照片诊断正确率:CR照片90%,传统屏-片73%。③摄影条件:CR系统比屏-片系统摄影管电压低4 kV,曝光量低4 mAs。结论:CR摄影影像质量好于传统屏-片摄影,可为临床提供可靠的诊断依据,且减少了病人的X线接受剂量。     

计算机X线摄影伪影及相应处理

目的:系统完整分析计算机X线摄影伪影,并寻求解决方法有效避免其再次发生。方法:收集各类伪影图像,并按照与成像过程的关联程度进行划分归类。结果:造成伪影出现的原因包括成像板因素、影像读取装置因素、图像后处理、激光打印机原因、操作者错误。结论:如果操作员能够认知产生伪影的原因,就能有效的消除。     

数字化影像相关成像链的质量控制探讨

目的:探讨影响数字化X线照片质量因素和各环节成像的质量控制.方法:回顾性地分析直接数字X线摄影(DR)和计算机X线摄影(CR)照片以及各成像环节(链)造成乙级片和废片的原因.结果:各成像环节成像过程中人为因素或设备故障造成了高乙级片率和废片率,合理监控是得到优质数字化照片的保证;了解各设备的功能、特点,发挥计算机后处理的优势是解决问题的关键.结论:做到设备配套合理化,操作程序的规范化,投照技术及计算机后处理功能熟练化,使数字图像照片完全符合临床诊断要求.     

计算机X线摄影图像伪影的处理

计算机X线摄影(CR)系统以其方便、快捷、图像清晰已在各级医院广泛使用。但在实际操作应用中发现CR图像的伪影直接影响图像质量,进而影响临床诊断。因此,有必要对其进行分析探讨,认识其表现形式及其产生的原因,并采取相应的措施加以处理从而有效的避免,以保证CR图像质量,提高影     

计算机X线成像茎突摄影体位的研究

目的 研究茎突计算机X线成像(XR)影像的特征，探讨茎突各种摄影体位的临床应用价值。方法 对茎突6个摄影体位的显示情况进行比较分析。结果 6个摄影体位能从多个方向显示茎突结构，其中茎突前后位和侧斜位最佳，可作为常规方法。结论 采用CR技术和合适的摄影体位可提高茎突摄影检查质量。     

CR与DR在下肢全长摄影中的应用比较

目的：探讨数字化摄影中,下肢全长CR1次成像和DR多次成像方法的实际应用。方法：40例被检者下肢全长CR1次曝光成像,在CR系统内合成下肢全长;40例DR系统进行多次曝光成像,在DR图像处理系统中合成下肢全长,对投照方法和图像的合成进行比较。结果：1次曝光CR组40例,多次曝光DR组32例,所合成双下肢全长图像清晰,能满足临床应力线的测量,下肢全长1次曝光CR成像操作简便,图像视觉连贯性和密度均匀性优于多次曝光DR成像。结论：下肢全长CR1次曝光更具有推广价值。     

Reducing the radiation dose during excretory urography: flat-panel silicon x-ray detector versus computed radiography

OBJECTIVE: The purpose of the study was to examine the possibilities for reducing radiation exposure in uroradiology using digital flat-panel silicon X-ray detector radiography. We compared the subjectively determined image quality of abdominal radiographs and urograms obtained on a digital flat-panel detector radiography system with those obtained on a computed radiography system. SUBJECTS AND METHODS. Fifty patients who had a clinical indication for urography underwent unenhanced abdominal imaging that was alternately performed using flat-panel silicon X-ray detector radiography or computed radiography. For patients who required a second radiograph with contrast medium, the examination modality was changed to avoid exposing the patients to excess radiation. The images obtained on flat-panel X-ray detector radiography were obtained at half the radiation dose of the images obtained on computed radiography (800 speed vs 400 speed). The resulting 50 pairs of images were interpreted by four independent observers who rated the detectability of structures of bone and the efferent urinary tract relevant to diagnosis and compared the image quality. RESULTS: At half the radiation dose, digital flat-panel X-ray detector radiography provided equivalent image quality of the liver and spleen, lumbar vertebrae 2 and 5, pelvis, and psoas margin on abdominal radiographs. The image quality obtained with digital flat-panel X-ray detector radiography of the kidneys, the hollow cavities of the upper efferent urinary tract, and the urinary bladder was judged to be statistically better than those obtained with computed radiography. CONCLUSION: With half the exposure dose of computed radiography, the flat-panel X-ray detector produced urograms with an image quality equivalent to or better than computed radiography.     

Perioperative validation of localisation of the mental foramen.

AIM: To assess the accuracy of panoramic radiography and spiral or computed tomography for the localisation of the mental foramen. MATERIALS AND METHODS: The distance from the alveolar crest to the mental foramen was measured from panoramic radiographs, spiral tomograms and CT scans. The same distance was measured during implant surgery using a specially designed caliper. RESULTS: Panoramic radiography showed more deviation (+0.6 mm) from the perioperative measurements than either spiral or computed tomography (+0.4 and -0.3 mm respectively). The difference was significant (P<0.05). In general, distances were overestimated on the panoramic radiographs. CONCLUSIONS: Cross-sectional imaging techniques are recommended for the pre-operative planning of implants in the posterior mandible.     

General equations for optimal selection of diagnostic image acquisition parameters in clinical X-ray imaging

The purpose of this work was to examine the effects of relationship functions between diagnostic image quality and radiation dose on the governing equations for image acquisition parameter variations in X-ray imaging. Various equations were derived for the optimal selection of peak kilovoltage (kVp) and exposure parameter (milliAmpere second, mAs) in computed tomography (CT), computed radiography (CR), and direct digital radiography. Logistic, logarithmic, and linear functions were employed to establish the relationship between radiation dose and diagnostic image quality. The radiation dose to the patient, as a function of image acquisition parameters (kVp, mAs) and patient size (d), was used in radiation dose and image quality optimization. Both logistic and logarithmic functions resulted in the same governing equation for optimal selection of image acquisition parameters using a dose efficiency index. For image quality as a linear function of radiation dose, the same governing equation was derived from the linear relationship. The general equations should be used in guiding clinical X-ray imaging through optimal selection of image acquisition parameters. The radiation dose to the patient could be reduced from current levels in medical X-ray imaging.     

An evaluation of different imaging chains in clinical chest radiography

Six imaging techniques in clinical chest radiography have been evaluated: four film-screen combinations in the conventional grid technique and two combinations in the air gap technique. Five parameters characterising the quality of a chest radiograph were evaluated by three radiologists and one chest physician by using a nominal grading scale from -2 to +2 compared with the standard technique. The quality parameters judged were: the visibility of peripheral lung vessels, lung parenchyme, the pulmonary hilum, and lung structure behind the heart shadow, as well as the visibility of miscellaneous findings of clinical interest. The air gap technique was shown to be superior to the ordinary grid technique. The diagnostic quality of chest radiography does not necessarily deteriorate with the screen speed. However, statistically significant differences were noticed, even between techniques which had equal speed and physical resolution.     

FotoCanvas软件在全脊柱摄影中的应用

目的：探讨FotoCanvas软件在数字化全脊柱摄影中的应用价值。方法：在数字化X线设备上,分次采集全脊柱的影像数据,获得67例受检者的原始图像160幅,在图像工作站上应用FotoCanvas软件合成75张数字化全脊柱图像。对拼接后的脊柱X线片进行评价。结果：拼接前后的图像甲片率差异无统计学意义（采用χ2检验,P〉0.05）。拼接后的全脊柱图像结构清晰,能对全脊柱进行临床诊断。结论：应用FotoCanvas软件实现数字化全脊柱的成像技术具有很好的应用价值。     

Comparison of radiation doses to patients undergoing standard radiographic examinations with conventional screen-film radiography, computed radiography and direct digital radiography

New flat-panel direct digital radiography equipment has recently been installed in our Accident and Emergency Department; its characteristics and versatility are well suited to the work undertaken in this environment. The aim of this study was to compare radiation doses to patients undergoing standard radiographic examinations using conventional screen-film radiography, computed radiography and direct digital radiography; entrance surface dose and effective dose were calculated for six standard examinations (a total of 10 projections) using standard patient exposure parameters for the three imaging modalities. It was found that doses for computed radiography (all examinations) were higher than the doses for the other two modalities; effective doses for direct digital radiography were approximately 29% and approximately 43% lower than those for screen-film radiography and computed radiography, respectively. The image quality met the criteria in the European guidelines for all modalities.     

Comparison of doses for bedside examinations of the chest with conventional screen-film and computed radiography: results of a randomized controlled trial

PURPOSE: To compare the radiation doses received by patients during bedside chest radiography when a computed radiography system was used and when a 400-speed screen-film system was used. MATERIALS AND METHODS: A randomized controlled trial was performed whereby all patients who were admitted to an intensive care unit were randomly assigned at admission to have all radiographic chest images obtained with either computed or conventional screen-film radiography. Doses were measured for 1 year, during which 269 patients underwent imaging. For these patients, surface entry doses were measured by means of individual thermoluminescent dosimeters placed on the skin at the center of the radiation beam. In addition, data were collected relating to the patient and examination characteristics, as well as to repeat examinations. Effective doses were calculated. RESULTS: The patients in the two arms of the study were well matched. The surface entry doses were higher in the computed radiography group (median, 0.21 mGy for computed radiography and 0.16 mGy for conventional radiography), and the effective doses were also higher (median, 0.036 mSv for computed radiography and 0.027 mSv for conventional radiography). Fewer examinations were repeated when computed radiography was used. CONCLUSION: When computed radiography was used, patient doses increased. The speed of this computed radiography system, which uses phosphor plate imaging, equates approximately to a 300-speed screen-film system.