微波体模

用水、盐,聚氯乙烯粉和羧甲基纤维钠四种材料配制成一种适用的微波体模(模拟肌肉组织)。该体模的复介电系数在300～2500MHz范围内与实际人体肌肉组织的误差≤5％。这种体模的优点是材料立足国内,价廉,室温下配制,使用方便。本文也给出这种体模的温度特性,稳定性和热学特性,供电磁场生物效应和微波热疗等研究使用。     

针对患者调强放射治疗计划的剂量学验证

目的建立针对调强放射治疗患者的剂量学验证方法。方法对100例患者进行的剂量验证共有3个测量项目一是采用小灵敏体积的电离室在仿人形模体中测量靶区剂量参考点(一般是射野等中心点)的绝对剂量,二是采用胶片测量一个治疗计划的所有射野在仿人形模体内形成的复合剂量分布,三是采用胶片或半导体探测器阵列在干水模体中测量单个射野的强度分布。由于完成全3个测量项目占用机器的时间过长,实际操作时采用自适应的方式,即首先测量靶区剂量参考点的绝对剂量,如果剂量误差在允许范围内,则不再进行其他的测量;如果剂量误差超出允许范围,则增加两个电离室测量点,并采用胶片测量横断面的剂量分布和(或)射野强度分布。结果93%患者的计划可以顺利实施,其他患者的计划需要调整铅门位置或完全重新设计。87%患者计划的剂量误差在临床可以接受的范围内,其他患者的计划需要对射野机器跳数进行修正;修正系统误差后,有96%患者计划的剂量误差在临床可以接受的范围内。结论利用已有的设备条件建立了患者调强放射治疗计划的剂量学验证方法,这种方法随着设备条件的改善和经验的积累还会进一步完善。针对患者的计划进行剂量学验证是很有必要的。     

电阻抗断层成像硬件系统的初步研究

各种原因导致的人体重要器官的缓慢出血等是导致病人死亡或预后较差的重要原因之一,目前的医学成像技术,包括CT、MRI、PET、超声等还无法对出血的过程进行长期、连续的床旁监测和监护。电阻抗断层成像是以目标体内电阻抗的分布或变化为成像对象的一种新型成像技术,作为一种廉价的无损伤检测技术,不使用核素或射线,无毒无害,因而可以成为对病人进行长期、连续图像监护的设备。本文介绍了一个基于物理模型的电阻抗成像硬件系统(FMMU V3),包括具有32个银复合电极的物理模型、采用DDS技术的恒流激励源、高精度信号检测模块、驱动测量模式程控设置模块、数据采集模块、数字I/O模块和高精度多路电源模块。该系统基于物理模型的测量数据经100次迭加后,测量精度在小信号时为1.0%,大信号时为0.1%。采用外触发DMA方式采集一组成像数据(32 X 31个)的时间小于1秒,基本满足了基于物理模型的动态成像要求,并给出了基于物理模型的初步动态成像结果。     

A multipurpose phantom for quality assurance of contrast-enhanced MR imaging of the breast

A phantom consisting of four components was developed to simulate contrast-enhanced MR imaging of the breast. These components included the correlation between the signal intensity and the contrast medium concentration, the uniformity of signals within surface coils, artefacts due to opposed-phase imaging effects, spatial resolution and the acquisition of relevant signal-to-time curves. Repetitive measurements demonstrated an excellent reproduction of phantom imaging with a deviation in signal intensity of approximately 5 %. The presented phantom allows the optimization of examination protocols as well as the comparison of different examination techniques. Furthermore, it enables the routine quality monitoring of contrast-enhanced MR imaging of the breast. Received: 28 May 1998; Revised: 3 September 1998; Accepted: 14 October 1998     

A prospective study on the neurological complications of breast cancer and its treatment: Updated analysis three years after cancer diagnosis

ObjectivesTo quantify the prevalence of neurological complications among breast cancer patients at one and three years after diagnosis, and to identify factors associated with neuropathic pain (NP) and chemotherapy-induced peripheral neuropathy (CIPN).Material and methodsProspective cohort study including 475 patients with newly diagnosed breast cancer, recruited among those proposed for surgical treatment (Portuguese Institute of Oncology, Porto). Patients underwent a neurological evaluation and had their cognitive function assesses with the Montreal Cognitive Assessment, before treatment and at one and three years after enrollment. We estimated the prevalence of each neurological complication, and odds ratios (OR), adjusted for socio-demographic and clinical characteristics, to identify factors associated with NP and CIPN.ResultsMore than half of the patients [54.7%, 95% confidence interval (95%CI): 50.2–59.2] presented at least one neurological complication, at one or at three years after cancer diagnosis. Between the first and the third year of follow-up, there was an increase in the prevalence of NP (from 21.1% to 23.6%), cognitive impairment (from 7.2% to 8.2%), cerebrovascular disease (from 0.6% to 1.5%) and brain metastasis (from 0.0% to 0.6%). The prevalence of CIPN decreased from 14.1% to 12.6%. Axillary lymph node dissection was associated with NP at one year (OR = 2.75, 95%CI: 1.34–5.63) and chemotherapy with NP at three years (OR = 2.10, 95%CI: 1.20–3.67). Taxane-based chemotherapy was strongly associated with prevalence of CIPN at one and three years.ConclusionNeurological complications are frequent even three years after cancer diagnosis and NP remained the major contributor to the burden of these conditions among survivors.     

Development and characterization of an anthropomorphic breast phantom for permanent breast seed implant brachytherapy credentialing

PurposeTo develop an anthropomorphic breast phantom for use in credentialing of permanent breast seed implant brachytherapy.Methods and MaterialsA representative external contour and target volume was used as the basis of mold manufacturing for anthropomorphic breast phantom development. Both target and normal tissue were composed of gel-like materials that provide suitable computed tomography and ultrasound contrast for brachytherapy delivery. The phantoms were evaluated for consistency in construction (target location) and Hounsfield unit (computed tomography contrast). For both target and normal tissue, the speed of sound was measured and compared to the image reconstruction algorithm's expectation value. Five phantoms were imaged preimplant and postimplant to assess interphantom similarity as well as to evaluate the uncertainty in quantifying seed position.ResultsThe average Hounsfield units of the target and normal tissue gels is −146 ± 5 and 23 ± 1, respectively. The average speed of sound of the target and normal tissue gels is 1485 ± 7 m/s and 1558 ± 9 m/s, respectively, resulting in an estimated 0.4 mm uncertainty in image guidance. The registration/deformation uncertainty was determined to be 0.8 mm. The standard combined uncertainty in assessing seed position spatial accuracy, also including a 0.9 mm estimate based on literature for seed localization, is estimated to be 1.3 mm.ConclusionsThe development of the anthropomorphic breast phantom and evaluation of both the consistency as well as overall seed position uncertainty illustrates the suitability of this phantom for use in brachytherapy end-to-end delivery and implant accuracy evaluation. When evaluating a user's implant accuracy, we estimate a standard combined uncertainty of 1.3 mm.     

多模型迭代重建算法对腹部体模CT扫描图像质量和辐射剂量的影响

目的 分析前置全模型迭代重建算法（ASIR-V）在腹部体模CT扫描中图像质量的变化规律及辐射剂量的降低程度,探讨优化图像质量和辐射剂量的最佳前置ASIR-V。方法 采用腹部仿真体模和Revolution CT机。根据噪声指数（NI）设置（6、8、10、12、14）分为5组。每组设置0~100%（间隔10%）前置ASIR-V扫描和常规扫描（即不联合迭代）,共获得55组图像。分析各NI组图像CT值、噪声、主观评分及辐射剂量随ASIR-V比例的变化规律。各NI组图像的主观评分比较采用秩和检验,CT值、噪声和辐射剂量比较采用单因素方差分析和配对t检验。结果 在0~40%前置ASIR-V水平,NI为6、8、10组图像主观评分基本稳定,NI为12、14组图像主观评分呈略升高趋势;50%~100%前置ASIR-V,各组主观评分均呈逐渐降低趋势;NI为6、8、10组,超过70%前置ASIR-V图像主观评分降至3分以下,NI为12、14组,超过60%前置ASIR-V主观评分降至3分以下;NI为6、8、10组,常规扫描图像主观评分与40%前置ASIR-V图像差异无统计学意义（P=0.626、0.915、0.514）,NI为12、14组,常规扫描图像主观评分略低于40%前置ASIR-V图像（P=0.041、0.036）;各NI组常规扫描图像主观评分均优于60%前置ASIR-V图像（（P=0.021、0.012、0.015、0.014、0.007））。各NI组中不同部位CT值、噪声随前置ASIR-V比例的增高呈基本稳定状态（P均>0.05）。各NI组CTDIvol随前置ASIR-V比例的增高,呈逐渐下降趋势。40%、50%和60%前置ASIR-V比例条件下,CTDIvol较常规扫描组下降比率分别为49.82%、62.51%、71.63%。结论 前置ASIR-V可在保证图像质量的条件下明显降低辐射剂量;腹部前置ASIR-V比例推荐40%~60%。     

Non-pharmacological management of phantom limb pain in lower limb amputation: a systematic review

Background: The incidence and severity of phantom limb pain (PLP) does not differ much between the extremities of amputation. However, its impact on functional ability and quality of life in lower limb amputation may be different, as prosthetic weight bearing is a key component in the movement and functional rehabilitation of individuals with a lower limb amputation.

Objective: To evaluate the evidence for effectiveness or efficacy of non-pharmacological interventions in the management of PLP in adults with lower limb amputation.

Methods: A comprehensive literature search conducted on 11 electronic databases, from their inception to 25 March 2016 identified 626 potentially relevant articles. Full-text randomised controlled trials in English which examined any form of non-pharmacologic intervention for managing PLP in lower limb amputees were included. The data with regard to characteristics of the studies, participants, intervention and outcome measures and overall statistical result were extracted. The Cochrane ‘Risk of bias assessment tool’ was used to assess the bias of all included articles.

Results: Four studies met the final criteria to be included in the review. Four treatment techniques had been used in the treatment of 204 patients with lower limb amputation. Two trials showed a positive impact of intervention on PLP compared to control group. Risk of bias varied across studies, and only one included study was assessed as having a low risk of bias.

Conclusion: The review identified lack of evidence to support non-pharmacological interventions in the management of PLP. Adequately powered high-quality trials are needed in this area to inform rehabilitation.