Clinical Radiation Physics Service

我们利用我们的高剂量率远程后加载机(HDR)，使用小而高强度的192Ir源进行组织间和腔间近距离放射治疗，开展了一系列的活动。该部门现在拥有两台最先进的瓦里安TrueBeam STX加速器，这两台加速器配备了120片叶高清晰度多叶准直器，叶宽薄至2.5毫米。这使得它们能够执行无框架立体定向放射外科(SRS)，尽管采购中包括一组直径从4 mm到25 mm的圆形准直器和SRS规划模块。除了传统的纵向、横向和垂直位置调整外，患者床还提供6自由度(6 DOF)，通过允许对俯仰、侧滚和偏航进行校正，大大提高了位置精度。这两个加速器的治疗输送参数匹配到0.5%以内，因此提供了真正的冗余，确保患者可以继续根据他们的分级计划接受治疗。这些机器包括Edge颅外SABR包，它将使它们能够使用基于植入的基准应答器和红外摄像机的射频局部定位的高级运动管理来提供无框架立体定向身体放射治疗(SBRT)。修订后的Edge套装包括Calypso射频定位系统，利用可植入的基准换能器和实时跟踪能力。实时光学跟踪利用升级的光学表面监测系统(VisionRT)系统来监测体表，并在表面变形(由于运动)时中断治疗，以及使用Calypso射频应答器监测前列腺位置并相应地门控治疗交付的前列腺癌放射治疗方案的临床实施。Rob获得了一台新的Elekta Flexitron 40通道高剂量率(HDR)远程近距离放射治疗后装载机，以取代其以前的单元。此外，Rob还收购了一个新的B-K超声设备，与以前的设备相比，它的成像能力有了很大的提高。我们已经购买了一个安装在沙发上的步进稳定器，以改进针插入方法，并正在努力为探头改装电动扫描系统，以加快图像采集。Rob有一个专门的近距离放射治疗套间(B2-3643)。该手术室现已投入临床使用，并已证明在手术和支持设备的布局上提供了更大的灵活性，这反映在患者在麻醉下的时间减少。Rob已经安装了替换的CT模拟器。虽然总体上与现有单位相似，但新系统在加速图像重建方面具有更强大的处理能力。它还使用双能量顺序CT扫描，可以进行后处理，以增强对碘、钙或其他可检测元素的检测，这些元素被用作肿瘤功能成像的生物示踪剂。ROB已经完成了向ARIA-RO版本16的过渡。它现在使用NIH活动目录系统，该系统提高了安全性，并利用虚拟服务器环境来增强操作可靠性。最后，Rob已转向新的IT主干，简化了位于贝塞斯达园区的Eclipse工作站和TrueBeam加速器与位于NCI Shady Grove数据中心的虚拟服务器场之间的通信。这提供了稳定的通信。ROB还对其Machine Shop进行了升级，以符合当前的电气标准，并允许安装更先进的制造设备，如3-D打印机和水射流切割机，以更好地支持临床研究项目。

We have a series of initiatives utilizing our High Dose-Rate Remote Afterloader (HDR) using a small, high intensity 192Ir source for interstitial and intercavitary brachytherapy. The department now has two state-of-the-art Varian TrueBeam STX accelerators which are equipped with 120 leaf high definition multi-leaf collimators with leaf widths as thin as 2.5 mm. This renders them capable of performing frameless stereotactic radiosurgery (SRS), although a set of circular collimators with diameters ranging from 4mm to 25mm and an SRS planning module are included in the acquisition. The patient couches also provide for 6 Degrees-of-Freedom (6DOF) to greatly improve positional accuracy by permitting corrections for pitch, roll and yaw, in addition to the traditional longitudinal, lateral and vertical position adjustments. The treatment delivery parameters of these two accelerators are matched to within 0.5%, thus providing true redundancy, assuring that patients can continue to receive their treatments according to their fractionation schedule. These machines include the Edge Extracranial SABR Package that will permit them to deliver frameless stereotactic body radiation therapy (SBRT) using advanced motion management based on radiofrequency local positioning using implanted fiducial transponders and infrared cameras. The revised Edge package includes a Calypso radiofrequency positioning system, utilizing implantable fiducial transducers and real-time tracking capability. The real-time optical tracking utilizes an upgraded Optical Surface Monitoring System (VisionRT) system to monitor the body surface and to interrupt the treatment if the surface distorts (due to motion) and the clinical implementation of a prostate radiotherapy protocol using Calypso RF transponders to monitor prostate position and correspondingly gate the treatment delivery. ROB has acquired a new Elekta Flexitron 40 channel High-Dose-Rate (HDR) remote brachytherapy afterloader to replace its previous unit. Additionally, ROB has acquired a new B-K ultrasound unit, which has vastly improved imaging capabilities relative to the previous unit. We have acquired a couch-mounted stepper-stabilizer to improve needle insertion methodology and are working on adapting a motorized scanning system for the probe to speed image acquisition. ROB has a dedicated brachytherapy suite (B2-3643). This room is now clinically operational and has proved to provide greater flexibility in the layout of operative and support equipment, which is reflected in reduced patient time under anesthesia. ROB has installed a replacement CT Simulator. While similar overall to the existing unit, the new system has substantially more powerful processing power to accelerate image reconstruction. It also utilizes dual energy, sequential CT scans, which can be post processed to enhance the detection of Iodine, Calcium or other detectable elements utilized as bio-tracers for the functional imaging of tumors. ROB has completed its transition to ARIA-RO version 16. This now utilizes the NIH Active Directory system, which improves security, and utilizes a virtual server environment to enhance operational reliability. Finally, ROB has shifted to a new IT backbone, streamlining communication between the Eclipse workstations and TrueBeam accelerators at the Bethesda campus and the virtual server farm located at the NCI Shady Grove Data center. This provides for stable communications. ROB has also upgraded its Machine Shop to conform with current electrical standards as well as permitting the installation of more advanced fabrication equipment, such as a 3-D printer and a water jet cutter, in order to better support clinical research projects.