Multi-Source E-Beam kV X-Ray Tube for Image-Guided Radiotherapy

描述（由申请人提供）：该项目将开发一种具有19个焦点的优化x射线管，可以放置在放疗系统的多叶准直器（MLC）的正下方和周围。通过将聚焦电子束（e-beam）按顺序引导到一系列19个冷却的钨靶上，该系统将提供一组投影图像，这些图像可以重建成围绕辐射目标的20厘米20厘米数字断层合成（DTS）体积图像。投影x射线由通用kV-MV成像仪捕获，该成像仪可以记录与层析kV图像序列交织的门户MV图像。由于源位于MLC的周长周围，因此生成的层析截面图像垂直于治疗光束的轴线对齐。这种几何图形被称为“光束眼视图”成像。DTS图像将用于为MLC的编程提供精确的肿瘤表面参考坐标，近乎实时。该系统的初步规格表明，每秒1个体积图像的重复率接近1毫米的空间分辨率是可能的。多源电子束x射线管将由开发原始Imatron EBCT扫描仪和最新电子束行李扫描仪的主要团队开发。由TeleSecurity Sciences， Inc.的科学家、顾问和供应商组成的电子束团队与加州大学戴维斯分校的顶级锥束CT团队以及瓦里安的一位重要顾问合作，瓦里安是平板x射线成像仪的权威人士，特别是kV-MV成像仪，该成像仪将在该项目中使用，同时提供肿瘤位置的MV门洞成像和交叉kV DTS成像。该项目的第一阶段将扩展初步工作，以更精确地确定未来商业系统的最终设计规范，该系统将适用于整个放射治疗行业。第二阶段的资金将用于开发多源电子束x射线管的合适原型，以证明商业系统的可行性和性能。大多数放射治疗供应商都为该项目提供了指导和支持信。在未来的放射治疗系统中，拟议系统的商业化实施将允许治疗计划在缩小的边缘内大大改善辐射照射的定位，超出恶性肿块的明显边界，并相应减少对周围正常结构的照射。这对于治疗自由呼吸时胸部和上腹部的肿瘤尤其重要，因为经常会遇到2厘米到5厘米范围内的周期性运动。[1]

DESCRIPTION (provided by applicant): This project will lead to the development of an optimized X-ray tube with 19 focal spots that can be placed immediately below and around the multi-leaf collimator (MLC) of a radiotherapy system. By steering a focused electron beam (e-beam) on a series of 19 cooled tungsten targets in sequence, this system will provide a set of projection images that can be reconstructed into a 20 cm 20 cm 20 cm digital tomosynthesis (DTS) volume image that surrounds the radiation target. The projection X-rays are captured by a universal kV-MV imager that can record portal MV images interlaced with the sequence of tomographic kV images. Since the sources are positioned around the perimeter of the MLC, the resulting tomographic cross section images are aligned perpendicular to the axis of the therapy beam. This geometry is referred to as "Beam's Eye View" imaging. The DTS images will be used to provide precise reference coordinates of a tumor surface for programming of the MLC, in near real-time. The preliminary specifications for the system indicate that a repetition rate of1 volume image per second with near 1 mm spatial resolution will be possible. The multi-source e-beam X-ray tube will be developed by substantially the same premier team who developed the original Imatron EBCT scanners and the more recent e-beam luggage scanner. The e-beam team consisting of TeleSecurity Sciences, Inc. scientists, consultants, and vendors has partnered with the premier cone beam CT team at UC Davis along with a key Varian consultant, who are authorities on flat panel X-ray imagers, and in particular the kV-MV imager that will be used in this project to provide simultaneous MV portal imaging with interlaced kV DTS imaging of the tumor position. Phase 1 of the project will extend the preliminary work to more precisely define the final design specifications for a future commercial system that will be appropriate for the entire radiotherapy industry. Phase 2 funding will develop a suitable prototype of the multi-source e- beam X-ray tube which will demonstrate the feasibility and performance of the commercial system. The majority of radiotherapy vendors have provided guidance and letters of support for this project. The commercial implementation of the proposed system in future radiotherapy systems will permit treatment plans that will have far improved localization of radiation exposure within reduced margins beyond the apparent boundaries of a malignant mass with a corresponding reduction in exposure to surrounding normal structures. This will be especially important in treating tumors of the chest and upper abdomen during free breathing where periodic motion in the range of 2 cm to 5 cm is often encountered. [1]