2009中华医学会影像技术分会第17次全国学术大会征文通知（第二轮）

经中华医学会学术会务部批准（项目编号：[2009]-Y12-01-64），中华医学会影像技术分会将于2009年9月在武汉市召开《2009中华医学会影像技术分会第17次全国学术大会》。本次会议的主题为“乳腺X线摄影和数字化成像”，会议同时举办《乳腺X线摄影和数字化成像》继续教育学习班，与会者可获国家级Ⅰ类学分10分。     

质量控制和管理在计算机X线摄影(CR)中的作用

计算机X线摄影系统与传统的X线照片相比，曝光量仅在传统X线摄影的1／2以下。其成像质量、宽容度、信息量都优于传统X线照片，且所得信息可按诊断要求处理，为X线影像长期保存和检索提供了可能性。现就CR系统的质量控制进行探讨。     

3种影像学技术和血清标志物对乳腺癌诊断的价值

目的：探讨3种非创性影像学技术超声（US）、全视野数字化乳腺X线摄影（MO）、磁共振成像（MR I）和血清CA15-3水平在乳腺癌诊断中的临床价值,以提高对乳腺癌的准确率。方法：回顾分析66例乳腺癌的超声、59例乳腺癌的全视野数字化乳腺X线摄影、30例乳腺癌的磁共振成像的影像学资料和测定58例乳腺癌患者血清CA15-3水平。结果：超声对乳腺癌的阳性诊断符合率为86.4%、全视野数字化X线摄影为93.2%、磁共振成像为96.7%、血清CA15-3为32.7%。超声、全视野数字化X线摄影和磁共振对乳腺癌的诊断符合率较高,CA15-3的诊断符合率较低。结论：超声、全视野数字化X线摄影、磁共振和血清CA15-3各有其特点,超声可作为乳腺癌首选检查方法。     

数字X线成像术探测器

数字化Ｘ射线成像技术提高了图象质量，使其能够进行医学图像处理、计算机辅助诊断及远程放射成像。图象质量与从病人身上透射过来的Ｘ线信息的准确探测紧密相关，即与Ｘ线探测器的性能关系密切。数字放射成像术的探测器必须适合它们被应用的特殊的放射学过程。主要的参数有：空间分辨率、响应均匀性、对比灵敏度、动态范围、探测速度。下面将对一些适合数字Ｘ射线成像的探测器技术进行回顾，探讨用于全方位探测器的设备及适于Ｘ线扫描系统的设备。     

直接数字化摄影临床应用体会

随着数字化摄影技术的高速发展,直接数字化摄影(direct radiographpy,DR)已普遍应用于临床[1].DR技术具有影像层次丰富,成像速度快,动态范围宽,分辨力高,X线剂量低等优势.利用DR优势为临床提供优质的影像信息是数字化摄影的目的.现将应用体会报告如下.     

线扫描磁共振成像方法

目的：在磁共振成像领域，线扫描是最早的一种傅立叶成像方法，后逐渐被二维傅立叶成像方法取代，近年来线扫描方法又重新引起了人们的兴趣，本文介绍磁共振线扫描方法，并分析其优缺点；方法：从线扫描与二维傅立叶成像方法的原理人手，在多个方面比较两种方法的差异；结果：线扫描方法在成像速度及图像信噪比方面不如二维傅立叶成像方法。但在克服运动伪影、金属伪影及手术过程中实时磁共振检查等方面优于二维傅立叶成像方法；结论：线扫描方法是一种适用于中低场永磁型磁共振设备的成像方法，在术中磁共振成像方面有广泛的应用前景。     

X线填充剂新载体羧甲基纤维素最佳配比的实验研究

目的：研究一种适宜于标本管道灌注后X线摄影和CT扫描三维成像的新型X线填充剂载体。方法：（1）6％、8％、10％、和12％羧甲基纤维素水溶液和4种不同比例的氧化铅／水：50g／L，100g／L，150g／L，200g／L，按正交设计调配成16种氧化铅／羧甲基纤维素水溶液配比悬浮液，做成20ml棒状铸件封装行CT扫描，以获得最佳配比。（2）使用最佳氧化铅／羧甲基纤维素配比悬浮液，进行SD大鼠全身血管灌注后，摄X线片和CT扫描三维成像。结果：SD大鼠X线摄影血管清晰，填充良好，光滑连续；小血管显示良好。血管三维图像主干及大分支饱满清晰，立体感强；边缘连续平滑，无齿状伪影；小血管显示三级以上。结论：最佳氧化铅／羧甲基纤维素配比：羧甲基纤维素的水溶液浓度为12％、氧化铅／羧甲基纤维素的配比为200g／L，羧甲基纤维素／氧化铅水凝胶可作为一种适宜于标本管道灌注后X线摄影和CT扫描三维成像的新型X线填充剂。     

乳腺癌钼靶摄影X线征象分析

目的探讨乳腺X线摄影对乳腺癌的诊断价值及X线征象，以提高乳腺癌诊断水平。方法对我院99例经手术或穿刺病理证实为乳腺癌患者的钼靶 X线征象进行回顾性分析。结果99例乳腺癌患者X线征象：直接见到肿块90例，毛刺征43例，钙化39例，未见明确肿块9例。结论钼靶X线摄影在乳腺癌诊断中具有较高的应用价值。     

数字X线摄影中散射线计算机补偿方法的研究进展

在数字X线摄影中，散射线造成了图像对比度的损失、噪声的增加，是使图像质量恶化的主要原因。为了提高数字X线图像的质量，必须采取有效措施减少散射线，减小对比度的损失。除了硬件减少散射线的方法外，国内外学者对数字X线摄影中散射线计算机补偿方法做了一些研究，本文对散射线计算机补偿方法的研究进展作一综述。     

工频X线机和中频X线机在胸部计算机X线摄影中应用分析

目的分析工频X线机和中频X线机在胸部计算机X线摄影(CR)中的图像质量,监测相应辐射剂量,比较两种X线机在CR摄影中的适用性。方法使用工频X线机和中频X线机摄取2～3岁小儿胸片共28例,分析图像质量,监测辐射剂量;并对两种X线机高压输出及IP对X线吸收特点进行分析。结果同工频X线机相比,中频X线机更易获得优质图像,且降低了辐射剂量。结论在CR应用中,中频X线机比工频X线机有明显优势。     

基于FPGA的数字X线实时显示处理系统

介绍了一套数字化X射线影像实时处理系统,重点对其中显示处理子系统进行了描述,并讨论了为实现图像的实时显示处理而采取的一些特殊设计.由于选用FPGA及多种优化结构设计,该系统较好地解决了医学图像显示过程中的大数据量处理与高分辨率实时显示等问题.系统具有很强的稳定性与可靠性.     

The contrast-detail behaviour of a photostimulable phosphor based computed radiography system

Contrast-detail measurements were performed on a computed radiography imaging system as a function of detector entrance air kerma over the dose range from 0.743 microGy (0.085 mR) to 277 microGy (31.8 mR). A theoretical model of contrast-detail behaviour for a photostimulable phosphor computed radiography system has been derived, which is based on a modified version of the Rose theory of threshold detection. Included in the model are both system and x-ray quantum noise terms, as well as the response of the eye. The zero-frequency noise power of the computed film images was measured with a double-beam scanning microdensitometer. For a given detector dose, good agreement was found between the predicted and measured data when this measurement of system noise was included in the model. The contrast-detail results obtained for the computed radiography system were also compared with contrast-detail results for an image intensifier-TV based digital imaging system and a conventional film-screen system.     

CR和DR图像后处理技术在活体茎突解剖学观测中的意义

目的探讨计算机X线摄影(computed radiography,CR)及直接数字化X线摄影(digital radiography,DR)图像后处理技术在活体茎突解剖学观测中的意义。方法210例茎突受检者CR、DR拍片后,行反转,边缘锐化,调节窗宽、窗位,放大,4种联合后处理,在显示茎突清晰的图像上分别测量茎突长度、前倾角和内倾角。结果茎突长(24.34±3.55)mm;前倾角(19.21±3.08)°;内倾角(24.16±4.28)°。左、右侧茎突长度、前倾角、内倾角度无显著差异。结论CR、DR图像联合后处理使活体茎突显示清晰,能做出更为准确、全面的观测,在茎突疾病的诊治和确定手术术式中具有指导意义。     

探讨DR颈椎斜位影像中应用组织均衡技术的优势

目的探讨颈椎斜位直接数字化X线摄影（direct digital radiography，DR）中，采用组织均衡技术的DR图像与标准DR图像的差别。方法利用中国医科大学附属第一医院引进的GE—Revolution XQ／Ⅰ型DR机对所摄的颈椎斜位影像中随机抽取100例作为分析资料。应用组织均衡技术对图像进行处理，同时与标准DR图像进行比较。结果应用组织均衡技术的图像，同一幅图像上不同部位的细节均可清晰显示；标准DR图像需调节不同的窗宽、窗位才能清晰显示或不能显示不同体厚部位的细节。结论在直接数字化X线摄影中，应用组织均衡技术能明显改善因受体厚度影响而难于观察部分的可视性，同时又不牺牲其他部分的细节显示，使DR的应用更完美。     

Scatter rejection and low-contrast performance of a slot-scan digital chest radiography system with electronic aft-collimation: a chest phantom study

Anti-scatter grids have been widely used to reject scatter and increase the perceptibility of low-contrast object in chest radiography; however they also attenuate the primary x-rays, resulting in a substantial degradation of primary information. Compensation for this degradation requires the use of higher exposure technique hence higher dose to the patient. A more efficient approach to reject scatter is the slot-scan imaging technique which employs a narrow scanning x-ray fan beam in conjunction with a slit or slot shaped solid state detector or an area detector used with an aft-collimator. With this approach, scatter can be rejected effectively without the need to attenuate primary x-rays. This paper demonstrates an electronic aft-collimation method, referred to as the alternate line erasure and readout (ALER) technique, for implementing the slot-scan digital radiography with a modern flat-panel detector. With this technique, instead of first exposing the detector and then reading the image line by line, the image line on the leading edge of the scanning fan beam is reset to erase the scatter accumulated prior to the arrival of the fan beam x-rays, while the image line on the trailing edge of the scanning fan beam is read out to acquire the image signals following the fan-beam exposure. These reset and readout processes are alternated and repeated as the x-ray fan beam scans across the detector. An anthropomorphic chest phantom was imaged to evaluate the scatter rejection ability and the low-contrast performance for the ALER technique and compare them with those for the anti-scatter grid method in full-field chest imaging. With a projected beam width of 16 mm, the slot-scan/ALER technique resulted in an average reduction of the scatter-to-primary ratios by 81%, 84%, 82%, and 86% versus 65%, 73%, 74%, and 73% with the anti-scatter grid method in the lungs, mediastinum, retrocardium, and subdiaphragm, respectively. The average CNR for the slot-scan/ALER technique was found to improve by 135%, 133%, 176%, and 87% versus 15%, 15%, 38%, and -11% with the anti-scatter grid method in the mediastinum, retrocardium, subdiaphragm, and lungs, respectively. These results demonstrated that the slot-scan/ALER technique can be used to achieve equally effective scatter rejection but substantially higher low-contrast performance than the anti-scatter grid method.     

Kinestatic charge detection

A new technique for detecting ionizing radiation in two dimensions, called "kinestatic charge detection," is proposed and analyzed. This technique is useful when the signal photons must be integrated, as in computed tomography and digital radiography, rather than counted, as in nuclear medicine imaging. A generic treatment of the technique with gas-, liquid-, or solid-state radiation detectors is presented. A theoretical analysis is given of the fundamental physical parameters required for kinestatic charge detection to be successful.     

Determination of the presampled MTF in computed tomography

A technique for measuring the presampled MTF in CT scanners is described. The technique uses a simple phantom consisting of approximately 0.050 mm aluminum foil sandwiched by flat plastic or tissue-equivalent slabs. The aluminum foil is slightly angled with respect to the reconstruction matrix, and CT images are acquired. The acquired CT image yields an angled slit image that can be used to synthesize the presampled line spread function (LSF). The presampled MTF is calculated from the presampled LSF. The technique is a direct extension of that proposed by Fujita et al. [IEEE Trans. Med. Imaging 11, 34-39 (1992)] for MTF calculation on digital radiography images. While the MTF in clinical CT scanners often reaches negligible amplitude below the Nyquist frequency, the technique is easy to implement, requires inexpensive materials, is robust to aliasing, and is more resilient to noise due to greater data averaging than conventional PSF-integration techniques. Use of the proposed technique is illustrated on a clinical multiple detector array scanner, and MTFs are shown for several common reconstruction kernels. It is likely that the proposed technique would be useful for all tomographic imaging systems, including single photon emission computed tomography, positron emission tomography, magnetic resonance imaging and ultrasound scanners.     

Cost of Managing Digital Diagnostic Images for a 614-Bed Hospital

The cost of recording and archiving digital diagnostic imaging data is presented for a Radiology Department serving a 614 bed University-Hospital with a large outpatient population. Digital diagnostic imaging modalities include computed tomography, nuclear medicine, ultrasound, and digital radiography. The archiving media include multiformat video film recordings, magnetic tapes, and disc storage. The estimated cost per patient for the archiving of digital diagnostic imaging data is presented.     

数字X线摄影组织均衡技术在胸腰段椎体病变的应用价值

目的探讨数字X线摄影（DR）组织均衡技术在胸腰段椎体病变诊断中的应用价值。方法80例骨折病人，其中男性66例，女性14例，年龄20～82岁，平均年龄52．5岁。用碘化铯非晶硅阵列数字平板探测器采集图像，行胸腰段椎体正侧位摄影，所有病人的侧位影像均行DR组织均衡技术后处理。由3位高级影像专家采用双盲法评价图像，并行统计学处理。结果胸腰段椎体病变32例，正常48例。胸腰段椎体侧位的常规DR与运用组织均衡技术处理的影像质量区别较大。差异有统计学意义。结论DR组织均衡技术对显示胸腰段椎体的侧位影像有较大的临床价值。