Improving the precision and performance of proton pencil beam scanning
Improving the precision and performance of proton pencil beam scanning
复制标题
提高质子笔形束扫描的精度和性能
DOI：
10.21037/599
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发表时间：
2012
影响因子：
0.9
通讯作者：
E. Pedroni
中科院分区：
文献类型：
--
作者：
S. Safai;C. Bula;D. Meer;E. Pedroni
在本报告中，我们介绍了PSI新的第二代扫描系统Gantry 2的技术特点。在第一台样机Gantry 1的经验和成功的基础上，Gantry 1于90年代建成，用于将笔形束扫描和IMPT引入质子治疗领域，我们最近实施了一种新系统，能够提供更快的重新绘制适形扫描，以便能够在图像引导下扫描治疗移动目标，这是质子治疗领域的下一个挑战。
新的技术开发与正在进行的2号机架基本调试同时进行，2号机架应于2013年投入运行，采用常规离散点扫描处理静态目标。
介绍了2号机架的创新布局以及在治疗区集成的图像引导基本设备。值得注意的是，滑动CT在患者床和独特的新的光束的眼睛查看X射线透视系统，以采取与质子束输送同步的光束方向的图像。
随着更快的扫描模式的发展，第一批初步结果看起来非常令人鼓舞。对于典型的0.5厘米范围步进，我们可以在80 ms内改变光束线的光束能量。我们可以在100 ms的时间内提供整个通量形状的能量层。通过改变扫描磁体的速度来绘制剂量线。笔形射束的瞬时剂量率也可以动态地变化。通过连接主机架射束监视器和离子源处的垂直偏转板的反馈回路精确控制剂量。
这些新的快速扫描模式应用于提供扫描与重绘，门控和跟踪治疗运动目标。我们的目标是开发笔形射束扫描作为一种通用的射束传输解决方案，能够最佳地治疗质子治疗的所有可能的临床适应症。然后，扫描可以完全取代市场上基于被动散射的旧光束传输方法。
Gantry 2的长期项目应该代表PSI在未来5-10年内对质子治疗领域的新贡献，通过提供从物理实验室到工业和诊所的直接转化癌症研究。
In this report we present the technical features of Gantry 2, the new second generation scanning system of PSI. On the basis of the experience and success with the first prototype, Gantry 1, built in the 90s for introducing pencil beam scanning and IMPT into the field of proton therapy, we have recently implemented a new system capable of offering much faster repainted conformal scanning for being able to treat moving targets with scanning under image guidance, the next challenge in the field of proton therapy.
The new technical developments are conducted in parallel to the ongoing basic commissioning of Gantry 2, which should go into operation with usual discrete spot scanning for treating static targets in 2013.
The innovative layout of Gantry 2 and the integration in the treatment area of the basic equipment for image guidance are presented. Noteworthy are the sliding CT within reach of the patient table and the unique new Beam’s-Eye-View X-ray fluoroscopy system for taking images in the beam direction synchronized with the proton beam delivery.
The first preliminary results with the development of much faster scanning modes look very encouraging. We can change the beam energy with the beam line within 80 ms for typical 0.5 cm range steps. We can deliver whole fluence-shaped energy layers within a time of the order of 100 ms. Dose lines are painted by changing the velocity of the scan magnets. The instantaneous dose rate of the pencil beam can be varied dynamically as well. The dose is precisely controlled with a feedback loop connecting the main gantry beam monitor with a vertical deflector plate at the ion source.
These new fast scanning modes should be used for providing scanning with repainting, gating and tracking for treating moving targets. The goal is to develop pencil beam scanning as a universal beam delivery solution capable of treating optimally all possible clinical indications for proton therapy. Scanning could then completely replace the old beam delivery methods based on passive scattering from the market.
The long term projects of Gantry 2 should represent the new contributions of PSI to the proton therapy field in the next 5-10 years, by providing direct translational cancer research from the physics laboratory into industry and clinics.