提高床旁X线摄影质量的探讨

目的通过床旁数字化X线摄影的实践,探讨保障床旁X线影像质量的方法。材料和方法数字化X线摄影设备(CR)、高频床旁X线机、铝滤过板、小照射野、适宜摆位、标准曝光。结果床旁X线影像的质量明显提高。结论使用数字化X线摄影设备合高频床旁X线机铝滤过板、控制照射野等综合措施可以提高床旁X线影像的质量。     

X线摄影焦点（F）-IP板的距离对CR成像质量的影响

目的探索X线管焦点(F)-IP板的最佳成像距离,提高CR图像质量。方法根据X线管焦点放大率和几何成像原理,求出最小焦点(F)-IP板的距离;综合考虑X机性能、被照体厚度和不同摄影部位,制定各部位摄影距离。结果现摄影距离CR图像质量明显提高,特别是四肢摄影X线曝光量显著降低。结论不同被照体厚度或不同部位,采用不同的摄影距离,在明显提高CR图像质量的同时,显著降低X线曝光量,减少被检者受照剂量,降低X线机输出功率,延长X线机使用寿命。     

医用直线加速器水平照射X线挡块的一种制作过程

医用直线加速器是一种比较复杂的大型医用设备 ,在治疗肿瘤过程中取得了相当可观的疗效 ,是肿瘤医院和放疗科不可或缺的一种治疗机器。在放疗过程中 ,为使射野形状与靶区形状的投影一致 ,将规则射野变成不规则射野 ,须在加速器上加挡块 ,这挡块一般放在滤过板上。由于Ｘ线的挡块又厚又重 ,当加速器机头水平照射时 ,Ｘ线挡块在滤过板上根本无法放置 ,所以必须将其固定在滤过板上。以下是加速器水平照射Ｘ线挡块的一种制作过程。物理室首先将滤过板用医院自己能加工的 5 -8ｍｍ厚的有机玻璃板替代 ,加速器的一系列治疗参数须重新测量、制表。…     

X线成像板计算机摄影系统的研制

本文介绍了X线成像板计算机摄影技术的基本原理,并就研制的X线成像板计算机摄影系统各组成部分进行了描述。文中还给出了试验结果。     

手术室床旁X线摄影辅助架的设计

目的 :研制一种用于手术室床旁的X线摄影辅助架。方法 :该装置由暗合固定板、托槽、拐臂、卡块、调节钮、凹槽和定位槽组成,其中托槽材质为胶木,其余都选用不锈钢材质。使用时经过卡块的凹槽将装置固定于手术床旁轨道上,固定板和托槽可放置并固定胶片暗盒(或成像板),可根据投照部位需要任意调节固定板和托槽的高度及角度。结果:该摄影辅助架可根据需要任意旋转和调节各种角度,升降及伸缩自如,可满足术中各类床旁辅助X线摄影检查。结论:该装置操作简单、快捷、灵活、方便、省时,解决了长期困扰手术室X线摄影时的暗盒(或成像板)固定和旋转问题,并且可减轻对医护人员和其他人群的辐射。     

S2001型野战X线车的数字化改造方案

S2001型野战X线车适用于野战医院进行野外常规X线透视和摄影检查。但其传统的屏一片摄影方式的局限性不利于其进行数字时代战场X线检查。针对数字化X射线摄影的特点，通过比较3种不同的数字平板X线探测器，提出了一种使用Canon CXDI X线平板探测器对S2001型野战X线车进行数字化改造对方案。     

一种用于X线摄影检查和各种床旁摄影的辅助摄影架装置

目的:研制一种用于X线摄影检查和各种床旁摄影的辅助摄影架装置.方法:该装置由摄影托板、燕尾槽、螺旋升降杆、托板固定架、固定滤线器等组成,利用带有燕尾槽的摄影托板放置和固定影像板或胶片暗盒,利用带有螺旋升降杆的托板固定架来调节摄影架的角度和高度,利用固定滤线器来减少散射线,以提高图像质量.结果:该辅助摄影架装置可根据病情需要任意旋转和调节各种角度和高度,升降及伸缩长度活动自如,适合各类床旁辅助X线摄影检查.结论:该辅助摄影架装置操作简单、快捷、方便、灵活,减少了对医护人员和其他人群的辐射,并且有效解决了X线摄影工作中所遇到的各种问题.     

五类型X线探伤机及机房的辐射防护性能分析

根据不同尺寸的水、油、气管道,压力容器,板材焊件无损检测的需要,用户购进周向或定向的各类型探伤机进行固定式和移动式X线探伤作业。然而,工作人员及邻近人员对各类X线探伤机与作业场所及周围环境的安全防护条件往往不明确而心存疑虑,X线探伤时的辐射安全问题颇令人关注。在检修设备或     

成像板对计算机X线图像质量的影响

在医学影像领域内计算机X线摄影正在取代普通X线摄影,新设备的引进使医学影像发生了质的变化,解决了图像的存储、传送和管理,CR(计算机X线摄影术)系统的关键在于使用了可接受模拟信息又可实现模拟信息数字化的成像板(简称IP板)代替了普通摄影中的屏/胶组合,从而实现了数字化影像的重建和显示以及网络传输和管理.IP板的正确使用对图像质量有着重要的影响.     

由单片机控制的X线机故障检修

较详细地分析了岛津10A-150D程控X线机无X线产生的故障原因,并根据故障发生原因从多个环节入手找出故障部位,介绍了X线机无X线产生故障时一般的分析方法。     

降低小儿胸部DR摄影辐射剂量的研究

目的:降低小儿胸部数字X线摄影(DR)辐射剂量,探索最优化的曝光参数。方法:通过设置附加铜滤过(0～0.3mm)和管电压(60～100kVp),采用自动曝光控制(AEC)先在等效小儿胸部的水模上放置线对卡进行卧位DR摄影,然后对各组图像进行空间分辨力、噪声水平评价,同时记录入射体表剂量和mAs。选最优化摄影参数对30例患儿进行胸部正位摄影,评价图像质量。结果:①各组图像分辨力辨认最高为2.5LP/mm,各组图像背景噪声均能接受;②采用0.3mm铜滤过入射体表剂量均低于其他滤过组,差异有统计学意义(q=5.368,q=2.29,q=2.98;P<0.05);③附加滤过相同,管电压为60～80kVp,入射体表剂量随kVp增加逐渐降低,当管电压为80～100kVp时则略有增加;④相同kVp时附加滤过增厚,入射体表剂量降低,管电流增加;⑤30例患儿胸部正位摄影图像均符合诊断标准。结论:设置管电压80kVp,0.3mm铜附加滤过,采用AEC进行小儿胸部DR为最优化摄影方案,可以降低小儿入射体表剂量。     

KVp选择对使用AEC的DR骨盆摄影的影响

选择不同的kVp对铝梯和骨盆模体一同进行摄影,分析自动处理后得到的铝梯像素值变化和各铝梯噪声变化,并对图像进行主观评价。结果表明:使用AEC时,kVp的选择影响图像质量和患者辐射剂量,90kVp～100kVp适合DR的骨盆摄影。     

A calibration comparison of mammographic kVp meters.

Modern screen-film mammography employs a molybdenum target and molybdenum filtration to obtain both high image contrast and low patient dose. Typical x-ray emission spectra are therefore dominated by molybdenum's characteristic radiation. The form of such spectra makes the accurate measurement of mammographic kVp difficult. Non-invasive digital kVp meters provide the simplest method of measuring mammographic kVp routinely, with a typical uncertainty of greater than +/- 1 kVp. With the expansion of breast screening, more stringent demands have been placed on these meters and recent calls for accuracies of better than +/- 1 kVp have been made. The responses of six popular mammographic kVp meters were compared in the range 22 to 32 kVp. Agreement between four of these meters above 24 kVp was within 1.8 kVp. The responses of the two remaining meters differed from the other meters by up to 5 kVp over the range. The results have highlighted the need for regular calibration checks on mammographic kVp meters and the provision of a national standard to which these calibrations can be traceable. Such a standard is currently not available in Australia.     

Investigation of the practical aspects of an additional 0.1 mm copper x-ray spectral filter for cine acquisition mode imaging in a clinical care setting

Minimizing the x-ray radiation dose is an important aspect of patient safety during interventional fluoroscopy procedures. This work investigates the practical aspects of an additional 0.1 mm Cu x-ray beam spectral filter applied to cine acquisition mode imaging on patient dose and image quality. Measurements were acquired using clinical interventional imaging systems. Acquisition images of Solid Water phantoms (15-40 cm) were acquired using x-ray beams with the x-ray tube inherent filtration and using an additional 0.1 mm Cu x-ray beam spectral filter. The skin entrance air kerma (dose) rate was measured and the signal difference to noise ratio (SDNR) of an iodine target embedded into the phantom was calculated to assess image quality. X-ray beam parameters were recorded and analyzed and a primary x-ray beam simulation was performed to assess additional x-ray tube burden attributable to the Cu filter. For all phantom thicknesses, the 0.1 mm Cu filter resulted in a 40% reduction in the entrance air kerma rate to the phantoms and a 9% reduction in the SDNR of the iodine phantom. The expected additional tube load required by the 0.1 mm Cu filter ranged from 11% for a 120 kVp x-ray beam to 43% for a 60 kVp beam. For these clinical systems, use of the 0.1 mm Cu filter resulted in a favorable compromise between reduced skin dose rate and image quality and increased x-ray tube burden.     

用非介入法检测诊断X射线机的管电压和曝光时间

目的 检测诊断X射线机的管电压和曝光时间。方法 采用CsI/光电二极管和单片机技术。结果 研制了一种非介入式kVp计。结论 利用此kVp计可一次曝光立刻得到管电压和曝光时间等信息。     

超低管电压（70 kVp）联合FLASH技术在儿童鼻旁窦CT中的应用

目的 探讨双源CT超低管电压（70 kVp）联合FLASH的扫描技术在儿童鼻旁窦检查中的可行性。方法 选取80例临床怀疑鼻旁窦炎的患儿随机分成A、B两组,实验组（A组） 40例：管电压70 kVp,螺距3.0,所得数据采用迭代算法（SAFIRE） 重建;对照组（B组）40例：管电压80 kVp,螺距1.5,所得数据采用滤波反投影算法（FBP）重建。分析比较2组不同扫描方式的主、客观图像质量以及辐射剂量,包括容积CT剂量指数（CTDIvol）、剂量长度乘积（DLP）,并计算有效辐射剂量（ED）。结果 患者所受的辐射剂量,实验组的CTDIvol （mGy）、DLP （mGycm）和ED （mSv）较对照组显著降低（CTDIvol：0.39 ±0.004 vs 1.57 ±0.009 mGy,P < 0.001;DLP：6.31 ±0.52 vs 19.88 ±2.01 mGycm,P < 0.001;ED：0.024 ±0.005 vs 0.079 ±0.016 mSv,P < 0.001）。较对照组,试验组的图像噪声及SNR_硬组织均有所增加,SNR_软组织则有所下降。2名医师对2组图像质量的主观评分无统计学差异（P ＞0.05）。结论 超低管电压（70 kVp）联合FLASH扫描技术可明显降低儿童鼻旁窦CT扫描剂量,且图像质量均满足诊断要求。     

Broad beam transmission properties of some common shielding materials for use in diagnostic radiology.

Broad beam geometry was used to measure the x-ray transmission properties of gypsum wallboard, steel, plate glass, and concrete for x-ray tube potentials of 50-125 kVp using an x-ray generator having a three-phase, twelve-pulse waveform and total initial beam filtration sufficient to provide half-value layers representative of those found in common practice and required by regulatory agencies. Measurement results are presented graphically and as numerical fits to a mathematical model of broad beam transmission to permit their use in the design of protective barriers for medical diagnostic x-ray facilities.     

数字化X线摄影在胸部检查中降低辐射剂量的价值

目的:探讨DR在胸部X线摄影中的剂量防护价值。方法:以胸部正位片摄影为测试体位,与传统X线机相同,均选择125kVp,自动化mAs,焦片距离180cm为前提进行曝光量对比。以22～25cm胸厚的患者在相同的曝光条件下设立传统与DR曝光量对照组。结果:DR曝光量降低了44.2%。结论:采用数字化X线摄影改进了胸部摄影质量,使工作流程更具先进性,提高了工作效率,并加强了对被检者的防护。     

辐射防护材料铅当量随X射线峰值管电压变化的研究

目的：研究不同能量X射线光子与辐射防护材料铅当量的关系，规范X射线防护材料铅当量的表示方式。方法：以五种常用的X射线防护材料为研究对象，分别找出每种材料的铅当量值随X射线管峰值管电压变化的规律。结果：含铅防护材料的铅当量随X射线峰值管电压变化不大；非含铅防护材料的铅当量随X射线峰值管电压变化较大。结论：X射线防护材料用铅当量表示射线屏蔽性能时，应标出检测时X射线峰值管电压。     

Reduction in MRSA environmental contamination with a portable HEPA-filtration unit

There is renewed interest in the hospital environment as a potentially important factor for cross-infection with methicillin-resistant Staphylococcus aureus (MRSA) and other nosocomial pathogens. The aim of this study was to evaluate the effectiveness of a portable high-efficiency particulate air (HEPA)-filtration unit (IQAir Cleanroom H13, Incen AG, Goldach, Switzerland) at reducing MRSA environmental surface contamination within a clinical setting. The MRSA contamination rate on horizontal surfaces was assessed with agar settle plates in ward side-rooms of three patients who were heavy MRSA dispersers. Contamination rates were measured at different air filtration rates (60-235 m(3)/h) and compared with no air filtration using Poisson regression. Without air filtration, between 80% and 100% of settle plates were positive for MRSA, with the mean number of MRSA colony-forming units (cfu)/10-h exposure/plate ranging from 4.1 to 27.7. Air filtration at a rate of 140 m(3)/h (one patient) and 235 m(3)/h (two patients), resulted in a highly significant decrease in contamination rates compared with no air filtration (adjusted rate ratios 0.037, 0.099 and 0.248, respectively; P < 0.001 for each). A strong association was demonstrated between the rate of air filtration and the mean number of MRSA cfu/10-h exposure/plate (P for trend < 0.001). In conclusion, this portable HEPA-filtration unit can significantly reduce MRSA environmental contamination within patient isolation rooms, and this may prove to be a useful addition to existing MRSA infection control measures.