Comparison of repositioning accuracy of two commercially available immobilization systems for treatment of head-and-neck tumors using simulation computed tomography imaging

PURPOSE: To compare the setup accuracy, comfort level, and setup time of two immobilization systems used in head-and-neck radiotherapy. METHODS AND MATERIALS: Between February 2004 and January 2005, 21 patients undergoing radiotherapy for head-and-neck tumors were assigned to one of two immobilization devices: a standard thermoplastic head-and-shoulder mask fixed to a carbon fiber base (Type S) or a thermoplastic head mask fixed to the Accufix cantilever board equipped with the shoulder depression system. All patients underwent planning computed tomography (CT) followed by repeated control CT under simulation conditions during the course of therapy. The CT images were subsequently co-registered and setup accuracy was examined by recording displacement in the three cartesian planes at six anatomic landmarks and calculating the three-dimensional vector errors. In addition, the setup time and comfort of the two systems were compared. RESULTS: A total of 64 CT data sets were analyzed. No difference was found in the cartesian total displacement errors or total vector displacement errors between the two populations at any landmark considered. A trend was noted toward a smaller mean systemic error for the upper landmarks favoring the Accufix system. No difference was noted in the setup time or comfort level between the two systems. CONCLUSION: No significant difference in the three-dimensional setup accuracy was identified between the two immobilization systems compared. The data from this study reassure us that our technique provides accurate patient immobilization, allowing us to limit our planning target volume to <4 mm when treating head-and-neck tumors.     

防颗粒物口罩过滤效率测试简易装置的研制与测试

目的生产性粉尘及环境空气雾霾防护口罩的过滤性能是其有效性的保证,研制口罩过滤性测试的简易装置。方法依据口罩过滤性能测试原理,重点进行口罩滤过材料固定装置和接口连接的设计。采用空气流量控制装置计量测试的气流量,采用口罩内外空气颗粒物浓度测定装置和分析软件进行口罩内外颗粒物水平测量和过滤效率计算。采用该装置对市售5个品牌50个口罩进行实际测试和分析。结果此装置轻便易安装,口罩边缘密封性能良好,口罩内外颗粒物浓度测试仪和呼气流量计均采用硅胶管套叠式连接方式,接口连接紧密且具有一定的硬度和弹性,保证了测试结果的可靠性和稳定性。实测50个不同型号口罩,4种N95型口罩过滤效率均满足要求,医用口罩滤料对颗粒物物的过滤效率低于N95型口罩。结论口罩滤过性测试简易装置,能满足不同类型防尘或防霾口罩的快速测试,适合非专业的口罩设计、销售或使用机构。     

医疗辐射危害与防护的研究进展

随着医学影像学的发展,医疗辐射防护的应用及其研究受到了广泛的关注。本文从医疗辐射的应用现状入手,阐述了医疗辐射对人体的危害,介绍了各种辐射防护的措施和原理,并展望了医疗辐射防护的未来。     

无粘胶敷料对长期使用无创呼吸机面罩所致压疮的预防效果

目的探讨无粘胶敷料保护长期使用无创呼吸机面罩患者鼻面部皮肤的临床效果。方法将86例长期使用无创呼吸机的患者按住院单双号分为两组,其中研究组43例使用无粘胶敷料,对照组43例使用粘性敷料,比较两组患者的面部皮肤状况。结果研究组压疮发生率为6．98％。明显低于对照组的20．93％,差异有统计学意义（x^2=4．44,P=0．035）。结论无粘胶敷料对于长期使用无创呼吸机面罩的患者的鼻面部皮肤有较好的保护效果。     

护理操作中不戴口罩对环境影响的细菌学研究

目的 探讨临床护理操作中不戴口罩的可行性。方法 取不戴口罩为实验组，戴口罩为对照组，将不戴口罩与戴口罩操作者置于细菌条件相同的环境中分别进行5、10、15、20min的相同操作，并在操作中安排相同的操作交流语言，在上述状态下，对操作前和操作中的环境进行细菌取样，送培养，每个时间段20例。然后将操作者口腔、鼻腔与环境中相同细菌(表皮葡萄球菌)进行细菌DNA同源性分析。结果 在同一时间段内，2组细菌计数差异无显著性(P＞0．05)；不同时间段内，2组细菌计数差异有显著性(P＜0.05)。操作者口腔和鼻腔中与环境中丽处来源的细菌经DNA检测没有同源性。结论护理人员身体健康、无呼吸道疾病进行临床护理操作，时间在20min以内，提示可以不戴口罩。     

BiPAP呼吸机经面罩通气在呼吸衰竭中的应用

目的研究无创双水平正压通气(B iPAP)对呼吸衰竭的治疗效果及改善疗效的因素。方法对40例慢性阻塞性肺病(COPD)处于早、中期呼吸衰竭患者,辅助施行B iPAP机面罩持续通气24h以上,观察治疗前后动脉血气及变化,病情加重时改建人工通气。结果本组40例患者治疗后各项临床指标均有不同程度的改善,且症状缓解快。其中有效40例,有效率达100%。结论选择合适的适应证,合理选择呼吸机、呼吸模式和治疗参数,并改善对B iPAP通气不利的影响因素,可以减少人工气道的使用,疗效肯定。     

鼻咽癌放射治疗摆位不确定度的研究

目的本研究探讨使用热塑面罩固定的鼻咽癌患者,在治疗过程的摆位不确定度。方法选择首次放疔的早期鼻咽癌患者19例,仰卧体位,个体化泡沫头枕,热塑面膜固定,将等中心点置于鼻咽腔附近,由三维激光灯在而罩上定出左、中、右3个原始十字标志点,并贴上直径约为0．3 mm的铅珠作为显像标记,然后行CT扫描。将CT图像通过网络传到Peacock的逆向计划系统进行计划设计,然后实施治疗。在治疗的一至六周,每周在CT模拟机进行重复扫描,共85次,扫描及固定和摆位方法都与进行计划CT时相同。将每周验证体位重复性的CT图像与计划CT图像通过读图软件进行比较。结果通过对19例患者的85次重复CT与计划CT比较,得出使用本面罩系统时,等中心点的平均位置坐标为(-0．84,+0．65,+0．01)mm；不同解剖骨性标记点在x、y、z 3个轴向的绝对位移值分别为(0．89±0．69),(0．82±0．79),(0．95±1．24)mm；等中心点三维矢量位移的平均值为1．87mm；等中心点三维矢量位移的95%可信区间(CI)最大值7．24mm,最小值2．03mm,平均值3．82mm；第一周到第三周等中心点二维矢量位移95%CI的平均值是4．17mm,第四周到第六周的平均值是5．12mm。结论使用连续CT多次重复扫描的方法来研究鼻咽癌治疗过程中的摆位不确定度是可行的。     

不同通气方式用于腹腔镜胆囊切除术的血气分析比较

目的：观察口咽通气道联合面罩给氧通气、喉罩通气及气管插管通气三种方式对腹腔镜胆囊切除患者血气分析的影响。方法选择本院收治需行腹腔镜胆囊切除患者300例作为研究对象,随机分为三组,每组100例,A 组采取口咽通气道联合面罩通气,B 组给予喉罩通气,C 组给予气管插管通气,比较三组患者血气分析相关指标差异及并发症发生率差异。结果A 组、B 组、C 组气腹后5 min PaCO2分别为（5．79±0．57）kPa、（5．73±0．56）kPa、（5．69±0．46）kPa,均高于气腹前 PaCO2, tA ＝16．231;tB ＝16．127;tC ＝16．387,P ＜0．05,三组比较无明显差异;A 组采取口咽通气道联合面罩给氧通气后术后并发症18例（18．0％）,低于 B 组术后并发症25例（25．0％）、C 组38例（38．0％）,χ2AC ＝32．262;χ2AB ＝15．687,均 P ＜0．05。三组胃膨胀情况比较无显著统计学差异;且三组均未出现返流。结论口咽通气道联合面罩通气、喉罩通气及气管插管通气均可应用于腹腔镜胆囊切除术,操作简便、安全,具有重要临床价值。     

A randomized crossover comparison between the Laryngeal Mask Airway-Unique™ and the air-Q intubating laryngeal airway in children

Objectives: The purpose of this randomized crossover study was to evaluate the feasibility of the air‐Q intubating laryngeal airway (ILA) in clinical practice when compared with the Laryngeal Mask Airway‐Unique^? (LMA‐U), the current standard of care for primary airway maintenance. Aim: We hypothesized that the ILA would have better airway seal pressures and laryngeal alignment than the LMA‐U in anesthetized nonparalyzed children. Background: The ILA is a newer supraglottic airway for children with design features that allow it to be used for primary airway maintenance and as a conduit for tracheal intubations. Methods: Fifty healthy children, 6–36 months of age, 10–15 kg, who were scheduled for elective surgery in which the use of a size two LMA‐U and size 1.5 ILA would be appropriate for airway maintenance, were enrolled into this randomized crossover study. Primary outcome measures were airway leak pressures and fiberoptic grades of view. Secondary outcome measures included ease and time for successful insertion, incidence of gastric insufflation, ventilation parameters, and complications. Results: There were no statistically significant differences in regard to the ease of device insertion, time to ventilation, gastric insufflation, and ventilation parameters between the ILA and the LMA‐U. All devices were successfully placed on the first attempt, and there were no instances of failure. There were statistically significant differences in the airway leak pressure between the ILA (19.0 ± 5.4 cmH₂O) and the LMA‐U (16.1 ± 4.9 cmH₂O), P = 0.001. There were also statistically significant differences in the fiberoptic grades of view between the ILA and LMA‐U, P = 0.004. Conclusions: The ILA had higher airway leak pressures and superior fiberoptic grades of view when compared with the LMA‐U and can be a suitable alternative to the LMA‐U in children weighing 10–15 kg.