超声医学图像非线性滤波算法研究进展

超声医学成像方法具有实时、无创、方便等优点，在临床上得到了广泛的应用。但由于超声医学成像机制的限制，超声医学图像质量不高。对图像进行滤波就是为了提高人眼和计算机对图像细节的识别能力。本研究讨论了应用于去除超声医学图像斑点噪声的非线性滤波算法的研究现状及其特点，重点介绍了基于中值滤波、小波变换、扩散方程的滤波方法，并把相关算法应用于超声医学图像的处理，直观地比较了各种滤波器的性能。最后展望了超声医学图像非线性滤波算法的发展方向。     

Online digital filters for biological signals: some fast designs for a small computer

After reviewing the design of a class of lowpass recursive digital filters having integer multiplier and linear phase characteristics, the possibilities for extending the class to include high pass, bandpass, and bandstop (‘notch’) filters are described. Experience with a PDP 11 computer has shown that these filters may be programmed simply using machine code, and that online operation at sampling rates up to about 8 kHz is possible. The practical application of such filters is illustrated by using a notch desgin to remove mains-frequency interference from an e.c.g. waveform.     

滑石粉酸中可溶物过滤介质探讨

目的:研究不同过滤介质对滑石粉酸中可溶物测定结果的影响。方法:采用不同标准收载的过滤介质(中速滤纸和慢速滤纸),以及孔径为0.45μm的微孔滤膜对不同粒径与粒径分布的滑石粉酸中可溶物进行测定,并对测定结果进行分析比较。结果:采用不同孔径的过滤介质测定,酸中可溶物检测结果及结果的相对偏差随着过滤介质孔径减小而下降。结论:现有各标准的过滤介质不一定适用各种不同粒径滑石粉酸中可溶物测定,采用孔径为0.45μm的微孔滤膜作为过滤介质,可以满足各种粒径规格滑石粉的试验要求。     

基于FPGA的两种高速高阶FIR滤波器的设计与比较

目的 设计满足全数字眼科超声系统高速高性能信号处理需要的数字滤波器.方法 用加入流水线级的并行乘累加方式和基于分割表的并行分布式算法设计基于现场可编程门阵列(FPGA)的32阶高速FIR低通滤波器,并在Quartus Ⅱ开发平台及Modelsim仿真平台上进行仿真验证.结果 2种方式设计的FIR滤波器经仿真验证,均满足设计要求.结论 通过对设计结果的分析比较,基于分割表的并行分布式算法设计的滤波器能在灵活配置资源占用的情况下,实现高速数据处理,为全数字眼科超声系统中滤波器的实现方法提供了选择的依据.     

深静脉血栓形成的介入治疗

目的 探讨对深静脉血栓形成（DVT）的患者进行介入溶栓治疗的选择原则和并发症的预防。方法 38例DVT患者放置下腔静脉滤器后进行血管腔内治疗，包括静脉腔内插管溶栓术38例、球囊扩张术14例和支架放置术2例。48h照腹平片观察滤器的位置．1周后行彩色多普勒检查了解下腔静脉和病变深静脉的通畅度。出院后定期复查滤器位置和患肢情况。结果 髂静脉、锁骨下静脉和肱静脉DVT的完全缓解率为100％，股静脉DVT完全缓解率为93．3％，小腿静脉DVT为68．4％；其余为部分缓解。滤器放置成功率为100％，溶栓过程中及追踪复查均未发生肺动脉栓塞。结论 深静脉血栓形成的患者进行介入溶栓治疗结合下腔静脉滤器放置术有效而安全，有较高的临床应用价值。     

Placebo-controlled challenges with perfume in patients with asthma-like symptoms

A group of nine patients with respiratory symptoms after nonspecific irritating stimuli, but without any IgE-mediated allergy or demonstrable bronchial obstruction, were referred to the asthma/allergy outpatient department for evaluation of suspected asthma. In order to find a provocation model and objectively assess these patients' symptoms in controlled studies, provocation with perfume or placebo was performed. The same patients were also subjected to perfume provocation with or without a carbon filter mask to ascertain whether breathing through a filter with active carbon could prevent the symptoms. The patients breathed through the mouth during the provocations, as they used a nasal clamp to prevent any smell of perfume. We found that the patients' earlier symptoms could be verified by perfume provocation. Breathing through the carbon filter had no protective effect. The conclusion is that symptoms suggesting hyperreactivity of the respiratory tract and asthma can be provoked by perfume without the presence of bronchial obstruction, and that using a carbon filter mask has no preventive effect. The symptoms are not transmitted via the olfactory nerve, since the patients could not smell the perfume, but they may have been induced by a trigeminal reflex via the respiratory tract or by the eyes.     

均整器对颅脑分次立体定向放疗剂量学影响

目的 探讨有无均整器的容积调强技术（VMAT）在颅脑分次立体定向放射治疗（FSRT）中的剂量学差异。方法 选择17例脑转移瘤患者,分别设计有均整器（FF）和无均整器（FFF）的VMAT计划。比较2组的靶区参数（D_98%、D_2%和D_mean）、适形指数（CI）、梯度指数（GI）、距离梯度（Gradient）、正常脑组织V_5Gy、V_10Gy、V_12Gy及D_mean,机器跳数（MU）、出束时间差异。结果 FFF-VMAT与FF-VMAT相比,GI、Gradient和出束时间都更低[(3.27 ±0.35) vs (3.33 ±0.37);(0.84 ±0.19) cm vs (0.85 ±0.2) cm;(142.71 ±34.59) s vs (177.05 ±62.68) s],差异有统计学意义（P值分别为0.001、0.002和0.001）。相比于FF-VMAT 计划,FFF-VMAT组计划的靶区的D_2%[(66.99 ±2.03) Gy vs (65.69 ±2.15) Gy,P = 0.001]和D_mean更高[(59.95 ±1.43) Gy vs (58.77 ±1.6) Gy,P = 0.000],且有统计学意义。FFF-VMAT及FF-VMAT计划靶区的D_98%、适形指数,正常脑组织的V_5Gy、V_10Gy、V_12Gy、D_mean,以及机器跳数差异无统计学意义。结论 FFF-VMAT模式可以更好的保护靶区周围正常组织,可以减少出束时间,提高治疗效率。     

医用直线加速器不同靶材料对X射线能谱的影响研究

目的:研究无均整过滤器(FFF)模式下不同靶材料对加速器能谱结构的影响,以及该模式下是否有必要切换靶材料以满足不同的临床治疗需求。方法:以基于蒙特卡罗算法(统计试验法)的EGSnrc程序用于电离辐射传输模拟,使用BEAMnrc建立VarianTrueBeam系列加速器机头结构,并设置不同材料和不同厚度的靶,使用BEAMdp调用其计算生成的相空间文件进行能谱与能量注量的结果分析比较。结果:在靶材料中厚度为0.2 cm的金靶在能谱结构表现较钽靶、钨靶更为优异,高原子序数材料光子能量注量差异不大,低原子序数材料铜靶在能谱与能量注量都不能满足使用要求。金靶在<2 cm厚度时具有很高的电子污染,低能光子份额高达20%,非平坦度高于80%,但较薄材料具有更高的能量份额与更低的热量损失,在常规模式较为适用。结论:FFF模式较常规模式提高了射野范围内光子的产生效率,高原子序数材料更适合作为靶材料,在常规模式切换到FFF模式时可以考虑同时切换靶材料以提高轫致辐射产生效率。     

化学药品注射剂生产所用塑料组件系统相容性研究思路浅析

化学药品注射剂生产过程使用的塑料组件系统与药液接触后可能产生相关浸出物,进而影响产品质量甚至危害患者安全。结合国内外已发布的相关标准及指南,对化学药品注射剂生产用的塑料组件系统（如硅胶管、滤器等）相容性研究的一般思路进行介绍。认为制剂申请人作为责任主体,应基于风险评估及必要时的试验研究,确认化学药品注射剂生产中使用的塑料组件系统的适用性。总结了目前申报资料中发现的相容性研究存在的问题,以期为药品研发及生产企业提供指导和帮助。     

Effect of charcoal filter on the emergence from sevoflurane anesthesia in a semi-closed rebreathing circuit

Purpose

A charcoal filter attached within the anesthetic circuit has been shown to efficiently adsorb halothane or isoflurane, thus hastening anesthetic recovery in low or minimal flow system. This study was intended to demonstrate whether the charcoal filter enhances the recovery time from sevoflurane anesthesia using a semi-closed circuit system.

Materials and Methods

Thirty healthy patients scheduled for elective surgery under sevoflurane anesthesia were randomly assigned to the charcoal filter or control group. Upon completion of surgery, the end-tidal concentration of sevoflurane was maintained at 2.0 vol%. A charcoal filter was attached to the expiratory limb of the breathing circuit of charcoal filter group subjects. After sevoflurane was discontinued, ventilation was controlled with the same minute volume as the intra-operative period at a fresh gas flow rate of 5 L·min^-1 with 100% O₂. The elimination kinetics of sevoflurane from end-tidal concentration, Bispectral index and times of eye opening and extubation were obtained.

Results

The exponential time constant (τ) of alveolar sevoflurane concentration in the charcoal filter group was significantly shorter than that in the control group (1.7±0.5 vs. 2.5±1.1 min, p=0.008). The charcoal filter hastened rapid eye opening (11.1±3.8 vs. 14.8±3.0 min, p=0.007) and extubation (11.9±3.9 vs. 15.3±3.2 min, p=0.014), compared to the control group.

Conclusion

A charcoal filter enhances the recovery from sevoflurane anesthesia with a semi-closed rebreathing circuit.