屏蔽结构医用直线加速器Halcyon机房的放射防护设计

以某医院核技术应用项目Halcyon加速器为例,通过分析相关射线参数与工作负荷,依据 NCRP No.151和GBZ /T 201,计算Halcyon机房各方向屏蔽墙所需的厚度和关注点的剂量率水平,对改建机房的屏蔽设计与施工方案进行优化,设计了经济可靠的放射防护方案,评估自屏蔽结构在屏蔽设计中的作用,并论证设计的自屏蔽加速器的防护方案效果符合相关法律法规与标准要求,为此类自屏蔽加速器项目的环评和控评提供参考。     

影像组学在肺癌中的应用研究进展

影像组学是从医学图像中提取大量的定量影像学特征,通过捕获整个肿瘤位置、范围、形态等和从3D图像中提取影像信息,旨在从临床影像学数据中提取肿瘤表型信息.已有大量研究表明,影像组学在肺癌的诊断和治疗中具有较大优势,影像组学已经发展成为辅助诊断、分析和预测肺癌转移的工具,现就影像组学在肺癌中的应用研究进展进行综述.     

Synthetic single crystal diamond dosimeters for Intensity Modulated Radiation Therapy applications

A synthetic single crystal diamond Schottky diode, in a p-type/intrinsic/metal structure, deposited by Chemical Vapour Deposition (CVD) and operating in photovoltaic regime, with no external bias voltage applied, was tested as a dosimeter for Intensity Modulated Radiation Therapy (IMRT) applications. The device response was compared with dose measurements from two commercial ionization chambers and a 2D diode array in an IMRT prostate cancer treatment plan. The obtained results indicate that CVD synthetic single crystal diamond-based dosimeters can successfully be used for highly conformed radiotherapy and IMRT dosimetry, due to their small size and high sensitivity per unit volume.     

RETRACTED: Reproducibility study of (TLD-100) dosimeters using an automated and manual TLD reader for radiotherapy applications

The precision of the response of Harshow thermoluminescent dosimeters (TLD-100) is investigated for two Harshow TLD readers. The mean reproducibility for chips pre-readout annealed at 100 °C for 15 min, evaluated with the manual planchet reader 4500, is 0.61% (1 standard deviation) using pre-readout method. When chips are evaluated with the automated hot-gas reader 4500, reproducibility values are undoubtedly worse, mean reproducibility for numerically stabilized dosimeters being equal to 2.12%(1 standard deviation) using pre-readout method also. The pre-readout method was used for elimination of lower temperature peaks in order to obtain more stability. These results indicate that the automated hot-gas 4500 reader, or, at least, the instrument used for the present measurements, is not adequate for chips evaluation, if precise and accurate dosimetry is required. The difference in precision for manual planchet reader is apparently due to geometry inconsistencies in the orientation of the planchet to imperfect chips faces during readout, requiring careful and manual reproducible arrangement of the selected chips faces in contact with the manual reader planchet. In order to elucidate this point, the planchet support face of all chips dosimeters was identified with a small point made by pencil, reducing in this way geometrical variations.     

胰腺癌不同调强方式的剂量学比较

目的 比较胰腺癌患者固定野调强放疗（FF-IMRT）与容积调强放疗（VMAT）的剂量学差异，为临床选择合适的照射技术提供参考。方法 选择10例胰腺癌术后患者，分别根据其同一CT模拟定位图像设计FF-IMRT计划和VMAT计划，处方剂量50Gy/25次。分析分析DVH曲线，评估靶区、危及器官和正常组织的剂量分布，并统计二者跳数（MU）和治疗时间的差别。结果 FF-IMRT计划和VMAT计划的靶区剂量分布均无有统计学差异。与FF-IMRT计划相比，VMAT计划中肝脏、胃、小肠、Body的V5出现有统计学意义的升高，而肝脏的V10和V20,胃的V10,小肠的V10、V20、V50，左肾的V20，右肾的V30、Dmean、Dmax，以及Body的V10、V20、Dmax有不同程度下降，脊髓的Dmax升高1.85Gy。另外，VMAT计划的MU数减少了126.9MU(20.48%)，治疗时间明显缩短。结论 胰腺癌患者选择VMAT计划，可以在不降低计划水平上的剂量分布的前提下，大大减少跳数，减少每次治疗时间。     

Experimental determination of the absorbed dose to water in a scanned proton beam using a water calorimeter and an ionization chamber

The absorbed dose to water is the reference physical quantity for the energy absorbed in tissue when exposed to beams of ionizing radiation in radiotherapy. The SI unit of absorbed dose to water is the gray (Gy = 1 J/kg). Ionization chambers are used as the dosimeters of choice in the clinical environment because they show a high reproducibility and are easy to use. However, ionization chambers have to be calibrated in order to convert the measured electrical charge into absorbed dose to water. In addition, protocols require these conversion factors to be SI traceable to a primary standard of absorbed dose to water. We present experimental results where the ionization chamber used for the dosimetry for the scanned proton beam facility at PSI is compared with the direct determination of absorbed dose to water from the METAS primary standard water calorimeter. The agreement of 3.2% of the dose values measured by the two techniques are within their respective statistical uncertainties.     

Nd:YAG激光、锶90β射线与压迫综合治疗耳垂增殖性瘢痕

目的：了解Nd：YAG激光、锶^90β射线与压迫综合治疗耳垂增殖性瘢痕的疗效。方法：将耳垂增殖性瘢痕病人69例分为两组，A组手术切除后采用Nd：YAG激光、锶^90β射线和压迫综合治疗，B组手术后仅使用锶^90β射线与压迫治疗，随访观察比较临床效果。结果：A组总有效率为82．86％，B组总有效率为67．64％。A组有效率高于B组。结论：手术后采用Nd：YAG激光、锶^90β射线和压迫综合治疗耳垂增殖性瘢痕效果明显。     

^90Y—树脂用于放射杀伤的实验研究

用Ｄｏｗｅｘ５０树脂吸附＾９０Ｓｒ－＾９０Ｙ平衡体制成＾９０Ｙ发生器，用柠檬酸钠缓冲液淋洗得到＾９０Ｙ，在ｐＨ≥８．０时，＾９０Ｙ与Ｂｉｏ－Ｒｅｘ７０树脂结合４ｈ，结合率达９０％以上，＾９０Ｙ标记树脂经动脉导管选择性地注入狗的右下肝叶，给药后＾９０Ｙ的总量药总剂量的１％，两周后Ｘ－ＣＴ或像显示，给药肝地呈液化性坏死，大体标叶观察见药肝叶萎缩，病理检查见肝细胞成片死亡，结果表明，＾９０Ｙ标记树脂是一     

子宫颈癌腔内放射治疗时的等剂量分布

子宫颈癌腔内放射治疗时盆腔组织等剂量分布的获得,对提高疗效、保护照射区内正常组织和器官是十分重要的。本文报道了应用非均匀组织等效仿真女性臀部模型、以 Buchler 后装装置在临床上使用的两种治疗方案为例,测量了盆腔组织额状面和穿过膀胱和直肠的矢状面上的等剂量分布,并对其中一种方案用蒙特卡罗方法计算了额状面上的等剂量分布。对于“A”点(耐受剂量极限点)的剂量率,测量结果的最大误差为5.4%;与 ISO 提供的曲线比较,两者对“A”点的相对偏差为3.0%;理论计算的统计误差为4.0%,理论计算与实测结果在5%以内符合。     

立体适形放疗与常规放疗对老年非小细胞肺癌的疗效比较

比较立体适形放疗与常规放疗对老年非小细胞肺癌的疗效,结果表明:立体适形放疗的治疗效果更有优势。