Blurring the lines for better visualisation

On-treatment imaging in radiotherapy has evolved over the last 60 years, bringing with it changes in the roles of radiographers, radiologists and oncologists. The ability to acquire and interpret high quality images (2D kilovoltage and megavoltage imaging and 3D CT and cone-beam CT) for radiotherapy planning and delivery requires therapy radiographers to have skills and knowledge that overlap with those of diagnostic radiographers. With the implementation of MRI-guided radiotherapy, treatment radiographers and clinical oncologists are exploring new territory, requiring truly collaborative working practices with their radiology partners. This short communication introduces the first images acquired using the hybrid MR Linac at our institution.     

医用直线加速器磁控管更换技术探讨

在医用直线加速器中通常都采用磁控管作为微波功率源。叙述了医用直线加速器中磁控管的结构及工作原理，并重点介绍在更换磁控管过程中需要注意的技术细节和对相关参数的调整。     

螺旋断层加速器与常规加速器在肺癌调强放疗中的剂量学评估初探

目的:分析、比较用于治疗非小细胞肺癌(NSCLC)的基于Helical TomoTherapy(HT)和常规加速器的调强放疗(IMRT)计划靶区剂量均匀性、适形度以及危及器官受照体积和剂量分布方面的差异,为HT技术进一步深入运用于临床工作提供了参考数据。方法:回顾性随机选择10例NSCLC患者,分别采用HT加速器和常规加速器对每例NSCLC患者行IMRT计划设计,然后比较靶区及危及器官(OARs)的剂量体积参数的差异。结果:在靶区方面,HT IMRT计划的靶区剂量均匀性指数(HI)和适形度指数(CI)均优于常规加速器IMRT(P=0.035、P=0.000)。在OARs方面,对于正常肺组织、V50、V30、V10、V5、平均剂量Dmean的差异有显著性意义(P=0.019、P=0.001、P=0.000、P=0.004、P=0.010)。就V5、V10、Dmean而言,HT计划高于常规加速器计划,就V20、V30、V50而言,HT计划低于后者。食管V35、Dmean的差异有显著性意义(P=0.006、P=0.015),而食管V55、心脏、脊髓等危及器官的受量基本相同。结论:对于NSCLC,基于HT的调强放疗能够提高更好的靶区适形度和均匀性,正常肺组织低剂量区受照体积增大,在临床应用中应予以注意。     

医科达数字化电子直线加速器控制软件IPV基本原理与应用解读

目的 介绍医科达数字化医用电子直线加速器控制软件里子项目和项目成分值(IPV)的工作原理,并具体说明控制软件通过三类子项目及其项目分项实时监测、控制子系统的运行状态。方法 首先介绍医科达数字化医用电子直线加速器的控制系统组成,然后介绍控制软件里子项目和项目分项的定义和分类,以及各类子项目的基本原理,最后通过分析高功率移相器的运动控制具体说明控制软件的子项目在实时监测、控制子系统运行状态的应用。结果 通过分析原理和举例详细、具体说明了控制软件IPV的工作原理及其应用,使用户尤其是维修人员能掌握相应理论知识,在日常使用和维修时能通过软件快速准确地查找运行参数,并根据相关子系统的控制原理分析问题和解决故障。结论 用户尤其是维修人员掌握这些子项目及其项目分项的工作原理,就能在日常使用或维修、校准时,快速准确地通过控制软件查看、校准运行参数,解决设备故障,并避免错误操作引起事故。     

医用电子直线加速器注入器系统故障定位专家系统模型设计

目的:探讨医用电子直线加速器注入器系统故障定位专家系统模型的实现。方法:医用直线加速器注入器系统故障诊断难度大,不确定性高,故需深入的分析总结基于对医用电子直线加速器注入器系统主要故障类型的故障机理。文章同时剖析了系统故障诊断机制的内容及特点。结果:针对直线加速器注入器故障诊断的特殊性提出了故障逆向推理机制,对推理机制的可行性进行了分析,得出了执行故障逆向推理机制的具体步骤,为系统故障诊断提供了理论依据。结论:利用故障树分析技术对直线加速器注入器故障定位方法切实有效,简单可行。     

Unity MR加速器临床应用各阶段时间统计分析北大核心CSCD

目的探索Unity MR加速器放疗系统在临床应用中各阶段的时间特征,为临床优化流程时间提供参考。方法回顾性研究使用Unity MR加速器治疗的患者55例,根据治疗计划方式分为位置自适应(ATP)和形状自适应(ATS)两组,统计对比两种治疗流程中各阶段所需时间、各部位的扫描序列名称和序列所需时长、计划射野数、子野数及跳数。此外,按治疗部位不同统计摆位时间。两种流程各分步时间及各部位摆位时间的结果采用中位数M(Q_(1),Q_(3))方式描述,各计划的子野数、射野数及跳数采用Mean±SD方式描述。结果行ATP治疗流程42例,共计305治疗分次:摆位、MR扫描、配准、自适应计划、出束、总时间分别为3(2,5)、5(4,7)、3(3,4)、8(4,12)、8(6,11)、30(25,36)min;行ATS治疗流程13例,共计65治疗分次:摆位、MR扫描、配准、靶区及OAR勾画、自适应计划、出束、总时间分别为2(2,3)、7(5,8)、4(3,5)、12(9,16)、11(10,14)、10(9,11)、55(49,61)min。按治疗部位统计摆位时间:头颈、胸、腹部分别为4(2,4)、2(2,4)、3(2,5)min;行ATP各计划的子野数、射野数及跳数分别为:头颈部8.1±1.7、49.9±31.2、846.75±363.44 MU,胸部8.0±2.0、60.7±13.3、790.21±279.00 MU,腹部9.7±2.0、81.2±22.3、2007.32±1053.81 MU;行ATS计划的子野数、射野数及跳数分别为:头颈部(仅1例)13、39、993.07 MU,腹部9.5±1.5、65.5±6.3、2763.26±835.41 MU。结论MR引导放疗具有较大临床应用潜力,目前整体治疗时间较长,但仍有改进的空间。     

Long-Term Outcomes After Linac Radiosurgery for Benign Meningiomas

AimsAlthough several studies on outcomes following stereotactic radiosurgery (SRS) for benign meningiomas have been reported, Linac-based SRS outcomes have not been as widely evaluated. The aim of this retrospective institutional single-centre study was to determine long-term outcomes of Linac-based SRS for benign intracranial meningiomas.Materials and methodsFrom July 1996 to May 2011, 60 patients with 69 benign meningiomas were included. All patients were treated with single-fraction Linac-based SRS with four to five non-coplanar arcs, dynamic or not. The marginal dose prescribed for the periphery was 16 Gy. Prognostic factors associated with local control, progression-free survival (PFS) and overall survival were tested.ResultsThe median follow-up was 128 months. No patient was lost to follow-up. The values observed at 1, 5 and 10 years were, respectively, 100%, 98.4% and 92.6% for local control, 94.9%, 93.2% and 78% for PFS and 100%, 94.7% and 92.7% for overall survival. In univariate analysis, local control after SRS was significantly higher for skull base and parasagittal meningiomas compared with convexity meningiomas (P = 0.031). Multivariate analyses showed significantly longer PFS when the minimum dose delivered to the tumour was greater than 10 Gy (P = 0.0082). No grade 5 toxicity was reported.ConclusionOur long-term results from a large sample size of benign meningiomas treated with Linac-based SRS confirmed excellent local control (>90%) and good safety, which is in line with published studies on Gamma Knife surgery. Above all, we showed significantly poorer PFS if the minimum dose to the tumour was under 10 Gy.     

金宝血透机AK200维修案例

金宝AK200自检能正常通过，但干粉桶进水不正常，然后电导报警。这是血透机使用过程经常会碰到的故障。文章根据图解详细分析了血透机的工作原理，根据故障现象准确查出故障原因所在，对同类设备的维修具有一定的指导意义。     

A simple, predictable intraoral technique for retentive mechanism attachment of implant overdenture attachments

A technique is presented for intraorally attaching two O-ring attachments to a mandibular complete denture. The technique involves fabricating and placing a mandibular denture with conventional procedures. Patients adapt initially to the complete denture. The attachments are then attached to the denture base with autopolymerizing acrylic resin. This technique provides a predictable method to achieve a tissue-supported and implant-retained overdenture.