目的：在医用直线加速器电子线模式和X射线模式下对机房屏蔽材料厚度进行快速估算,减少手工计算所引起的繁重工作并减少计算过程中的错误。方法：参照国内外已有的辐射防护屏蔽计算经验,分析医用直线加速器不同工作模式下对工作人员和公众的危害因素进行计算机程序设计,编制完成后与实际屏蔽参数进行对比。结果：通过与医用直线加速器治疗室实际屏蔽效果验证进行比较,医用电子直线加速器治疗室辐射屏蔽计算软件的计算结果与参考经验公式进行计算的结果相吻合。结论：医用电子直线加速器总治疗室辐射屏蔽计算软件可用于对医用电子直线加速器治疗室屏蔽材料的厚度进行估算,能够大幅简化繁琐的计算过程,并使计算结果更为准确可靠。

Objective:To develop a simulation program by the name of “Shielding Calculation Software of Medical electron accelerator Treating room”, which based on the common model of radiation protection shielding calculation. We can use this program to estimate the thickness of shield when Medical electron accelerator is work on the Electron model and X-ray model, avoiding onerous work and error by handwork calculation.Methods: Considering the available radiation protection shielding calculation experience, and analyzing the hazard factor to staff and public, when we finish the program, we may contrast the simulation results with the actual shielding results. Results: The simulation program was completed, and the simulation results were carried out by this program. By considering the actual shielding effect, we find that the simulation results are very close to the results based on the empirical formulation.Conclusion: This computer method is very convenient to estimate the thickness

剂量对比研究对确保临床试验的统一辐射剂量给药具有相当重要的意义。本文研究了拉合尔国际剂量学调查团以及核医学与肿瘤学协会（INMOL）所做的X射线高功率直线加速器的性能对比分析。实验采用基于国际原子能机构（IAEA）关于吸收剂量-水剂量标准TRS-398协议的柱形电离室进行测量，偏差百分比为0．5％-1％。研究发现拉合尔INMOL关于直线加速器输出特性的实验结果与IAEA剂量调查团的研究结果一致。

The dosimetric inter-comparison studies carry pertinent significance to ensure uniform radiation dose delivery for clinical trials .This paper investigates the comparative performance analysis of an X-ray high power linear accelerator per-formed by the International Dosimetry Survey Mission and Institute of Nuclear Medicine&Oncology (INMOL) ,Lahore . The measurements were made using cylindrical ionization chambers based on the International Atomic Energy Agency (IAEA) TRS-398 protocol for absorbed dose-to-water dosimetric standards ,and the percentage deviation was found to be between 0 .5% -1% .The dosimetric analysis concerning linear X-ray accelerator output performed by INMOL ,Lahore was found to be in good agreement with the results of IAEA Dosimtery Survey Mission .

目的选用一个合适的计算方法对X射线能量大于10 MV的工业探伤用直线加速器机房进行屏蔽计算,确定屏蔽厚度。方法以一台DZ-12/5500型工业探伤用直线加速器机房为研究对象,参考NCRP 151号报告、GBZ/T220.2—2009等资料中提供的计算方法进行计算和分析。结果该加速器机房有用线束方向混凝土屏蔽墙厚度需278 cm,其它三面墙分别需要182、195、204 cm;顶盖厚度为110 cm混凝土时,天空反散射在距机头20 m处造成的剂量当量率非常小;"Z"字型迷道入口处总周剂量当量为115.69μSv,其中X射线的散射和泄漏辐射总剂量当量为2.43μSv/周,中子辐射剂量当量为102.96μSv/周,中子俘获γ射线剂量当量为10.30μSv/周。结论对实际建成运行的机房检测结果的分析后发现,上述计算值与检测值比较吻合,说明本文选用的计算方法和选取的参数可行。

Shielding calculations were performed for the room of a linear accelerator of model DZ-12/5500 , with NCRP Report No .151 ,GBZ/T 220 .2—2009 and etc as references ,to illustrate how to select a suitable calculation method to determine the optimal shielding thickness of room for industrial flaw detecting linear ac-celerator of energy above 10 MV .It shows that a 278 cm thick concrete shielding wall is needed in the useful beam direction ,while the concrete thickness in other 3 sides should be 182 ,195 and 204 cm respectively . With a roof of 110 cm thick concrete ,sky inverse scattering results in an extremely small dose equivalent rate in any location 20 m away from the nose of the accelerator .The ambient dose equivalent is 115 .69μSv in the Z-shaped labyrinth entrance ,in which X-ray scattering and leakage ,neutron irradiation ,and neutron capture of X-ray give rise to 2 .43 ,102 .96 and 10 .30 μSv/week respectively .Analysis of test results upon operation indicates that

目的：分析并研究瓦里安公司新型直线加速器TrueBeam型号光子束的长期稳定性。方法：采用Standard Imaging公司的QA BeamChecker Plus采集TrueBeam系统6 MV光子线长期日检数据,并进行系统性分析,评价参数包括中心轴剂量、平坦度及对称性。结果：18个月的日检数据分析结果显示,6 MV的X射线中心轴剂量偏差为（0.0%±0.7%）,仅1次检测结果〉2%;平坦度稳定性好,偏差为（0.1%±0.1%）;轴向对称性偏差和横向对称性偏差测量结果均在±1%以内。结论：TrueBeam医用加速器系统的6 MV光子束具有非常稳定的剂量输出特性。

Objective:To study the long-term stability of 6MV photon beam on TrueBeam, which is a new linear accelerator introduced by Varian Medical System. Methods:QA BeamChecker Plus (QABC+, Standard Imaging Inc., Middleton, USA) was used to measure 6MV X-ray on TrueBeam linac as daily quality assurance (Daily QA). Dosimetric parameter, including output Constancy, flatness and symmetry, were employed to evaluate the dose delivery stability of TrueBeam linac. Results: Daily QA results of 18 months showed the dose output delta was (0.0%±0.7%), only once out of tolerance of 2%. The constancy of Flatness was excellent with the delta of (0.1%±0.1%). The symmetric of axial and transverse varied within 1%. Conclusion:The output constancy of TrueBeam with 6MV is very stable, as well as flatness and symmetry. It’s stable and reliable to implement Truebeam linear accelerator in clinical.

目的观察银杏叶提取物对放射性中耳炎动物模型早期中耳放射性损伤的防护作用。方法44只健康豚鼠，随机分为模型对照1天组、模型对照30天组、银杏叶提取物治疗1天组、银杏叶提取物治疗30天组、空白对照组。以医用直线加速器6MV-X射线照射豚鼠左耳，3.0Gy/次，每周5次，总剂量45Gy。加用银杏叶提取物治疗的豚鼠每次照射前注射EGB0.4ml/kg，模型对照组注射同体积生理盐水，空白对照组不作处理。分别于照射剂量达45Gy后第2天和第30天处死动物，采集标本，行光镜及扫描电镜检查，比较各组豚鼠照射侧中耳黏膜病理改变和超微结构变化。结果射线剂量达45Gy后第2天，见中耳黏膜上皮增厚，炎性细胞浸润，纤毛倒伏、融合，渗出增多；照射后第30天，见中耳黏膜上皮纤毛脱落、减少，损伤加重；在照射前应用EGB的豚鼠，显示中耳黏膜损伤减轻；未用药组较用药组中耳黏膜厚度及白细胞浸润数均增高(均P＜0.05)。结论放射线可致中耳黏膜黏液纤毛输送系统功能受损，并随时间推移而加重；银杏提取物可以减轻中耳黏膜的早期放射损伤，并随时间的延长而有进一步的改善。

Objective To investigate the therapeutic effect of Ginkgo Biloba extract (GBE) on the earlier mucosa damage in middle ear induced by radiation among animal models. Methods Forty-four adult guinea pigs were randomly divided into 5 groups, i.e. model control group 1 (tested on the 2nd day following radiotherapy ended), model control group 2 (tested on the 30th day following radiotherapy ended), EGB treating group 1 (tested on the 2nd day following radiotherapy ended), EGB treating group 2 (tested on the 30th day following radiotherapy ended) and blank control group. Animals in the first four groups were exposed to X-rays radiation at a total dosage of 45 Gy, which was administered to the left ear of each guinea pig at 3.0 Gy each time and 5 times per week, by use of a linear accelerator 6MV-X. Animals in EGB treating groups were treated with 0.4 ml/kg EGB injected intra-peritoneally 30 min before radiation each time, while those in model control groups were injected intra-peritoneally wi