DR and CR: Recent advances in technology

After some initial reluctance, nowadays transition from conventional analogue-to-digital radiographic technique is realized in the vast majority of institutions. The eventual triumph of digital over conventional technique is related to its undoubted advantages with respect to image quality and improved image handling in the context of a picture archiving and communication system.CR represents the older system, which matured over decades and experienced some important recent improvements with respect to dose efficiency and work-flow efficiency that strengthened its position. It represents a very versatile, economically attractive system that is equally suited for integrated systems as well as for cassette-based imaging at the bedside.DR systems offer superb image quality and realistic options for dose reduction based on their high dose efficiency. While for a long time only integrated systems were on the market suited for a large patient throughput, also mobile DR systems became recently available.While for the next years, it is likely that DR and CR systems will coexist, the long term perspective of CR will depend on further innovations with respect to dose efficiency and signal-to-noise characteristics while for DR economical aspects and broader availability of mobile systems will play a role.     

中药酸枣仁、龙齿、石菖蒲对小鼠脑组织单胺类神经递质及其代谢物的影响

应用高效液相色谱－电化学检测器观察中药酸枣仁、龙齿、石菖蒲对小鼠脑组织中单胺类神经递质及其代谢物含量的影响。结果显示：酸枣仁可降低多巴胺和３，４－二羟基苯乙酸的含量，龙齿降低多巴胺和高香草酸水平。开窍中药石菖蒲能降低５－羟吲哚乙酸及上述三种神经递质。乙醇组则明显升高３，４－二羟基苯乙酸和５－羟吲哚乙酸的水平。从上述结果说明安神、开窍单味中药可能是通过降低单胺类神经递质起到使中枢神经镇静的作用。     

应用探测器定位摘出眼眶内金属异物

目的：探讨应用探测器定位摘出眼眶内金属异物的利和弊。方法：对1986－1998年连续在我科住院，术中应用探测器定位并摘出异物的132例（132眼）进行回顾分析。结果：探测器术中定位的准确性为100％，而摘出成功率为131／132（99．24％），失败1例（0．76％）；手术未造成视力的进一步下降；有13例术后致上睑下垂和眼外肌功能障碍,其中约半数病例经中医治疗得以治愈和改善。结论：本探测器对最大长径＞1.5mm的眶内金属异物能准确定位，位于外下象限距角膜缘平面之后≤25mm之磁性异物摘出较易；位于角膜缘平面之后≥26mm之非磁性金属异物是否手术，应具体分析，权衡利弊。     

催化燃烧与红外吸收原理可燃气体探测器探讨

工业生产中得到广泛应用的可燃气体探测器主要有两种不同检测原理,即低温催化无焰燃烧和非色散红外吸收原理。文章分析了催化燃烧原理适应性、温度补偿的实现、线性输出的机理以及它依赖氧气、某些气体使其丧失催化性能等应用局限性;同时,分析红外吸收原理中红外波长的选择,光路、光源和吸收器等对探测器性能的影响;并指出两种原理各有特点和优点,针对不同场合正确选型,使可燃气体探测器可靠运行,保障环境安全。     

Intraoperative localization of early-stage upper gastrointestinal tumors using a magnetic marking clip–detecting system

Background Intraoperative tumor localization often is difficult during laparoscopic surgery for early-stage upper gastrointestinal tumors. Method This study enrolled 15 patients undergoing laparoscopic gastrectomy. A magnetic marking clip–detecting system was used to apply a marking clip to the tumor site during preoperative gastroscopy, and to detect a marking magnetic body. Results In a basic ex vivo study, the mean permeance rate on the gastric wall serosal surface was 0.97 ± 0.01. Magnetic flux densities required for exploration were 52.6 mT on the gastric wall serosal surface and 312.4 mT 10 mm away from the surface. In a clinical study, the mean distance between the detected tumor site and the clip along the longitudinal axis was 8.3 ± 3.2 mm. The mean detection time was 5.7 ± 2.3 min. Conclusion The magnetic marking clip–detecting system may be useful for tumor site detection during laparoscopic gastrectomy.     

医用X线成像系统的数字化进展

医学影像技术是医学放射诊断学中最活跃的研究领域之一,而X线成像技术是医学成像的主要技术。文中介绍了医用X线成像系统由传统的成像方式向着数字化方向发展的过程中先后出现的CR、DR成像系统及其优缺点,着重论述了CR成像系统的改进和DR成像系统的关键部件——X射线探测器的种类并预测了X线成像系统的发展趋势。     

An eco-friendly HPLC-UV method for the determination of risedronate in its bulk and tablet dosage form with application to content uniformity,dissolution and stability testing

Risedronate is a nitrogen-containing bisphosphonate for the treatment and prevention of postmenopausal osteoporosis. The current work aims to develop a novel green HPLC-UV method for the rapid analysis of risedronate sodium in bulk and tablet formulation. The analyzed samples were separated on Waters Atlantis dC18 (150 mm × 3.9 mm; 5 μm) column using a green mobile phase consisting of potassium phosphate buffer pH 2.9 and potassium edetate buffer pH 9.5 in a ratio of 1:2, the final pH was adjusted to 6.8 with phosphoric acid, the mobile phase was pumped at a rate of 1.0 mL/min, with column temperature set at 30 °C, eluted samples were detected at 263 nm and the chromatographic run time was 3.0 min. The method was found to be linear over the concentration range of 14–140 μg/mL with a correlation coefficient (r²) of 0.9994. Accuracy and precision were evaluated from three QC samples (LQC, MQC and HQC) together with the five calibrators where the percentage accuracy was found to be 101.84%. Processed quality control samples of risedronate sodium were tested for stability at different conditions, short term, long term and freeze- thaw stability. The current method was further extended to study the content uniformity of Actonel® tablets following United States Pharmacopoeia (USP) guidelines. The proposed method was fully validated as per ICH guidelines.     

塑料薄膜覆盖探测窗对表面污染检测的影响

目的 研究塑料薄膜包裹表面污染检测仪探测窗对表面污染检测的影响。方法 选取RDa150型、Como170型两款表面污染检测仪分别在无膜、单层膜、双层膜覆盖设备观察窗的条件下测量镅-241源α表面污染水平。结果 无膜条件下,RDa150型表面污染检测仪5次测量结果平均为228.01 Bq/cm²,Como170型表面污染检测仪平均为231.05 Bq/cm²;单层膜覆盖条件下,RDa150型表面污染检测仪5次测量结果平均为96.34 Bq/cm²,Como170型表面污染检测仪平均为100.31 Bq/cm²,下降约一半;双层膜覆盖条件下,RDa150型表面污染检测仪5次测量结果平均为0.45 Bq/cm²,Como170型表面污染检测仪平均为0.65 Bq/cm²。结论 表面污染水平较高时,可用单层塑料薄膜覆盖设备探测窗,降低设备被污染风险;去污完毕或表面污染水平较低检测时,不能用塑料薄膜包裹设备探测窗。     

基于小波变换和神经网络的心电信号P波检测

为了提高P波检测准确率,利用小波变换模极大值对在多尺度上的变化规律能表征信号突变点的性质,结合人体生理特性的检测策略进行心电信号P波的跨尺度检测。同时,引入反向传播神经网络对已检出的准P渡再次进行确认与识别。经MIT数据库实验表明,P波检测准确率达到97％。     

探测器阵列在TPS模型调整中的应用

目的 探讨探测器阵列在Monaco模型MLC参数调整中的应用可行性。 方法 先固定其中一个参数,再改变另一个参数,评估参数变化对测试野3ABUT、7SegA及FOUR L γ通过率影响,确定MLC参数leaf transmission与leaf offset。测试中对随机选择的 12例不同解剖部位的肿瘤病例,用Octavius 4D系统分别进行Step & Shot与dMLC计划的二维剂量验证(机架角归零)和VMAT计划的三维剂量验证,以3%/3 mm的标准分析γ通过率。再分别对三种调强计划进行点剂量验证分析其剂量偏差。 结果 确定leaf transmission、leaf offset参数值为0.01、-0.08 mm。模型调整前后,三种调强计划剂量分布验证平均通过率分别为(88.59±2.94)%、(87.81±3.28)%、(87.45±2.24)%和(98.45±1.23)%、(98.90±1.01)%、(96.03±1.66)%,点剂量验证平均剂量偏差分别为(0.85±0.75)%、(0.95±0.39)%、(0.98±0.40)%和(0.97±0.57)%、(1.08±0.76)%、(0.86±0.45)%。