Low-dose hypersensitivity in nucleus-irradiated V79 cells studied with synchrotron X-ray microbeam

This study aims at elucidating the cellular responses induced by energy deposition in the cell nucleus or cytoplasm in the low-dose (< 1 Gy) region. We compared the survival fraction of V79 cells irradiated with X-ray microbeams of different sizes. Entire cells or cell nuclei were targeted with 5.35 keV monochromatic X-ray microbeams using a synchrotron radiation (SR) X-ray microbeam irradiation apparatus. Using a threshold of 30 cells/colony after 60 h of incubation, conditions that had been proven to give results equivalent to those of the conventional method, we determined the survival fraction of the microbeam-irradiated cells. When cell nuclei were irradiated with 10 x 10 microm (2) X-ray beams, the survival fraction was almost the same as that obtained with 50 x 50 microm (2) beams except in the low-dose region. In the low-dose region irradiated with 10 x 10 microm (2) beams, hyper-radiosensitivity (HRS) was clearly observed in the nucleus-irradiated cells, and the survival curve exhibited a minimum of about 60% at 0.5 Gy. This may be the most distinct HRS reported thus far when an asynchronous population is used. Difference in observed HRS phenomena is solely due to the irradiated part in the cell. These results suggest that energy deposition in the cytoplasm might suppress the HRS.     

Heavy-ion microbeam system at JAEA-Takasaki for microbeam biology

Research concerning cellular responses to low dose irradiation, radiation-induced bystander effects, and the biological track structure of charged particles has recently received particular attention in the field of radiation biology. Target irradiation employing a microbeam represents a useful means of advancing this research by obviating some of the disadvantages associated with the conventional irradiation strategies. The heavy-ion microbeam system at JAEA-Takasaki, which was planned in 1987 and started in the early 1990's, can provide target irradiation of heavy charged particles to biological material at atmospheric pressure using a minimum beam size 5 mum in diameter. A variety of biological material has been irradiated using this microbeam system including cultured mammalian and higher plant cells, isolated fibers of mouse skeletal muscle, silkworm (Bombyx mori) embryos and larvae, Arabidopsis thaliana roots, and the nematode Caenorhabditis elegans. The system can be applied to the investigation of mechanisms within biological organisms not only in the context of radiation biology, but also in the fields of general biology such as physiology, developmental biology and neurobiology, and should help to establish and contribute to the field of "microbeam biology".     

立体定向放疗在肺癌脑转移瘤治疗中的作用研究

目的 对比研究全脑放疗(WBRT)联合立体定向放射治疗(SRT)与联合三维适形放射治疗(3D-CRT)局部肿瘤加量治疗肺癌脑转移的疗效与耐受性.方法 2009～2010年所收治92例肺癌脑转移瘤患者(脑转移病灶≤3个),随机分组WBRT加3D-CRT:46例,WBRT加SRT:46例.评价指标为中位生存期(MST)和放疗毒性,全组患者中位随访时间12月,随访率100％.结果 全组中位生存期为8.9个月,其中3D-CRT组8.6个月、SRT组9.4月(x2=0.22,P＞ 0.05).放疗后3个月肿瘤局部控制率分别为71.7％、63％.结论 SRT是肺癌脑转移瘤患者的一种有效治疗手段,对脑转移瘤≤3个的患者,3D-CRT与SRT局部肿瘤加量生存期差异无统计学意义,放疗不良反应亦无明显差异,但SRT治疗2次比3D-CRT治疗13-15次在放疗时间上占优势.     

Stereotactic body radiotherapy for kidney cancer: a 10-year experience from a single institute

The purpose of this retrospective study was to investigate survival outcomes and irradiated tumor control (local control [LC]) and locoregional control (LRC) after stereotactic body radiotherapy (SBRT) for T1 or recurrent T1 (rT1) kidney cancer. Twenty-nine nonconsecutive patients with 30 tumors were included. SBRT doses of 70 Gy, 60 Gy or 50 Gy in 10 fractions were prescribed with a linear accelerator using daily image guidance. The Kaplan–Meier method was used to estimate time-to-event outcomes, and the log-rank test was used to compare survival curves between groups divided by each possible factor. The median follow-up periods for all patients and survivors were 57 months and 69.6 months, respectively. The five-year LC rate, LRC rate, progression-free survival (PFS) rate, disease-specific survival (DSS) rate and overall survival (OS) rate were 94%, 88%, 50%, 96% and 68%, respectively. No significant factor was related to OS and PFS. Three of 24 non-hemodialysis (HD) patients had new-onset-HD because of the progression of underlying kidney disease. Grade 3 or higher toxicities from SBRT did not occur. In conclusion, SBRT for kidney cancer provided a high rate of LC, LRC and DSS with minimal toxicities, but patient selection and indication for SBRT should be done carefully considering the relatively low OS rate.     

Stereotactic radiosurgery

Stereotactic radiosurgery is the accurate focusing of ionising radiation onto an intracranial target, and was pioneered in Sweden in the early 1950's. It has proven effective in the treatment of arteriovenous malformations, acoustic tumours and many other small brain lesions. In the last decade the commercial availability of a gamma ray system has led to other centres following the work in Stockholm; more recently, various techniques utilising linear accelerators, (LINACs), have been developed. Both types of system necessitated special dosimetry and treatment planning methods for the small, high dose-gradient circular fields. Localization of the lesions requires angiography, computerised tomography (CT) or magnetic resonance imaging (MRI).     

Polymer gels impregnated with gold nanoparticles implemented for measurements of radiation dose enhancement in synchrotron and conventional radiotherapy type beams

Normoxic type polyacrylamide gel (nPAG) dosimeters are established for dose quantification in three-dimensions for radiotherapy and hence represent an adequate dosimeter for quantification of the dose variation due to the existence of the gold nanoparticles (AuNPs) in the target during irradiation. This work compared the degree of polymerisation in gel doped with nanoparticles (nPAG-AuNP) with control gel samples when irradiated by various sources. Samples were irradiated with a synchrotron radiation source of mean energy 125?keV, 80?kV X-ray beams from superficial therapy machine (SXRT), 6?MV X-rays and 6?MeV electron beams from linear accelerator. Analysis of the dose-response relation was used to determine a dose enhancement factor (DEF) of 1.76?±?0.34 and 1.64?±?0.44 obtained for samples irradiated with kilovoltage X-rays energy from synchrotron source and SXRT respectively. Similarly, including AuNPs in gel results in a DEF of approximately 1.37?±?0.35 when irradiated by an electron beam and 1.14?±?0.28 for high energy X-ray beams. The results demonstrate the use of AuNPs embedded in polymer gels for measuring the enhancement of radiation caused by metallic nanoparticles.     

立体定向适形放射治疗技术

立体定向适形放射外科治疗（Ｂｏｄｙ Ｓｔｅｒｅｏｔａｃｔｉｃ Ｃｏｎｆｏｒｍａｌ Ｒａｄｉｏｔｈｊｅｒａｐｙ）就是利用直线加速器产生的Ｘ线,应用多叶准直器进行射束成形,产生与肿瘤外形轮廓一致的射束形状,对肿瘤进行分次、大剂量、多角度的非共面适形照射。本文简要介绍与体部立体定向适形放射外科治疗有关的几个技术。     

Stereotactic body radiotherapy for Stage I lung cancer with chronic obstructive pulmonary disease: special reference to survival and radiation-induced pneumonitis

This retrospective study aimed to evaluate radiation-induced pneumonitis (RIP) and a related condition that we define in this report—prolonged minimal RIP (pmRIP)—after stereotactic body radiotherapy (SBRT) for Stage I primary lung cancer in patients with chronic obstructive pulmonary disease (COPD). We assessed 136 Stage I lung cancer patients with COPD who underwent SBRT. Airflow limitation on spirometry was classified into four Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades, with minor modifications: GOLD 1 (mild), GOLD 2 (moderate), GOLD 3 (severe) and GOLD 4 (very severe). On this basis, we defined two subgroups: COPD-free (COPD −) and COPD-positive (COPD +). There was no significant difference in overall survival or cause-specific–survival between these groups. Of the 136 patients, 44 (32%) had pmRIP. Multivariate analysis showed that COPD and the Brinkman index were statistically significant risk factors for the development of pmRIP. COPD and the Brinkman index were predictive factors for pmRIP, although our findings also indicate that SBRT can be tolerated in early lung cancer patients with COPD.     

苍白球靶点立体定向术磁共振定位

目的：探讨用新的一种立体定向MRI成像技术个体化直接显示定位苍白球靶点。方法：48例帕金森病苍白球毁损术，采用快速反转恢复序列MRI连续薄层扫描。直接显示双侧苍白球、壳核和视束，测出苍白球边界、内髓板和壳核内缘旁开脑中线距离，苍白球膜后核（PVP）宽度。结果：81％病例苍白球内则部（Gpi)和外侧部（Gpe)边界以及内髓板被清晰显示，直视下手术靶点定位于PVP中央。不同个体或同个体左右半球苍白球的位置存在显著差异（P＜0．05），苍白球旁开中线距离变异可达10mm。PVP宽度左侧大于右侧（P＜0．05）。结论：单独依前后联合中点（MCP）解剖间接定位苍白球靶点容易出现偏差，而采用MRI特殊序列成像能使苍白球靶区及周围结构直接显示，术中PVP微电极值测穿刺减少，毁损靶点电生理定位更简捷和准确。     

Stereotactic radiosurgery planning with ictal SPECT images

This paper is motivated by a clinical requirement to utilise ictal SPECT images for target localisation in stereotactic radiosurgery treatment planning using the xknife system which only supports CT and MRI images. To achieve this, the SPECT images were converted from raw (pixel data only) format into a part 10 compliant DICOM CT fileset. The minimum requirements for the recasting of a raw format image as DICOM CT or MRI data set are described in detail. The method can be applied to the importation of raw format images into any radiotherapy treatment planning system that supports CT or MRI import. It is demonstrated that the combination of the low spatial resolution SPECT images, depicting functional information, with high spatial resolution MRI images, which show the structural information, is suitable for stereotactic radiosurgery treatment planning.     

医用无框架立体定向导航系统的工业设计

无框架立体定向导航系统是一种医疗外科机器人,目前国内的这类产品在形态、色彩等外观要素上,大多是直线条、冰冷的、笨重的风格。这种视觉语言,会加重病人及医护人员治疗时的厌恶感,降低治疗效果。本文在分析现代国际获奖医疗产品设计特点后,深入产品人机工学因素的研究,确定了一些约束条件:机械关节臂的可调范围、高度、截面形状和工作站的高度等,在此基础上对无框架立体定向导航系统进行具体的设计。     

超级伽玛刀立体定向放射治疗的质量控制

目的:探讨肿瘤超级伽玛刀立体定向放射治疗定位和摆位的质量控制(QC)和质量保证(QA)。方法:采用面膜、真空袋等固定患者体位,行PET-CT或CT扫描定位,靶区内CT扫描层厚为3 mm,通过计算机网络传输到物理室TPS计划系统,进行靶区勾画、计划设计和计划验证等,在超级伽玛刀行回转拉弧立体定向放射治疗。结果:超级伽玛刀立体定向放射治疗明显提高肿瘤局部控制率(TCP),降低周围正常组织放射并发症(NCTP),急性毒副反应轻,大大提高肿瘤疗效和患者生存质量。结论:超级伽玛刀立体定向放射治疗是目前有效治疗恶性肿瘤的重要手段。     

立体定向放疗在复发胶质瘤中的应用

目的：对近年来立体定向放疗在复发胶质瘤中的应用进展进行评述。方法回顾胶质瘤复发的类型,介绍了立体定向放疗治疗复发胶质瘤的照射剂量、照射范围及疗效,分析了立体定向放疗单用或与药物联合治疗复发胶质瘤的情况。结果胶质瘤复发多数是在初次放疗野内;立体定向放疗是复发胶质瘤进行再次照射时的选择。立体定向放疗可分为单次及多次,联合替莫唑胺、贝伐珠单抗等药物会显著提高疗效。结论立体定向放疗治疗复发胶质瘤有很好的疗效,在照射剂量、照射范围及联合药物等方面需进一步研究。     

立体定位射波手术平台

对于损伤、肿瘤和身体的任何部位接受放射治疗的情况提供治疗计划，图像引导的立体定位放射手术和精确放射治疗。     

新型全身立体放射治疗设备--立体定位射波手术平台(CYBERKNIFE)

介绍新型全身立体放射治疗设备---立体定位射波手术平台(CYBERKMFE)的设备结构,技术特点及医疗优势     

体部X线刀立体定位对CT扫描的特殊要求

在CT上进行立体定位是实施C线刀治疗的第一步，定位扫描与常规扫描相比较，有一些特殊的要求，目的是避免在本阶段产生误差，保证X线刀精确实施。本文根据作者的实际经验，详细分析了在进行立体定位时容易出现误差的环节和原因，并提出了相应的解决方法，以及需要特别提出关注的关键步骤。