A Coaxial Plasma Accelerator for Proton Radiotherapy

描述（由申请人提供）：质子放疗在美国和世界各地都在增长。这种增长是由于质子在商业上的可用性，以及在物理上的优势，即可以将大部分辐射剂量沉积在肿瘤中，而不是像x射线那样，大部分剂量沉积在正常组织中。在美国，目前有5个质子治疗中心和2300多个基于x射线的直线加速器设施在治疗患者。质子放射治疗在普通癌症患者群体中的广泛应用受到资本、建设和运营成本的限制，每个地点的质子放射治疗费用超过1亿美元，与基于x射线的设施相比，这是一个巨大的成本差异。一种引人注目的方法是将质子治疗的物理优势结合到一个更小、更便宜、可以广泛传播的龙门架安装或固定线路系统中，以改进放射治疗。本文描述了利用同轴等离子体质子加速的方法的发展和研究。斯坦福大学等离子体物理实验室最近在等离子体加速器中特殊高速操作模式的理解和稳定方面取得了突破，这导致了一种加速器概念，有可能使负担得起的紧凑质子治疗成为可能。这项可行性研究的目的是将现有的加速器发展到：1。测试和光束表征：这项任务包括使用各种光学诊断和使用磁扇形能谱仪测量相空间特性。核轨迹探测被用作一种应急手段，以在大范围的操作条件下表征光束。2. 增加等离子体加速器束能量：这项任务包括各种参数的优化和缩放，如电极形状和尺寸、电路参数、质量流量和电源电压。这项任务还包括开发一种新的氢气喷射系统。3. 光束动力学建模：使用Geant4软件评估了使用紧凑磁铁/准直器组件进行能量分散和选择的可行性。目标是研究光束传输和准直的方法，同时最大限度地减少和捕获有害的二次辐射和中子。该项目的长期目标是开发下一代质子治疗装置，通过广泛推广紧凑的单间质子治疗系统来改善人类健康。

DESCRIPTION (provided by applicant): Proton radiotherapy is growing in the US and around the world. This growth is due to the commercial availability of protons and the physical advantages of the improved ability to deposit most of the radiation dose in the tumor, as opposed to x-rays where most of the dose is deposited in normal tissues. In the US there are currently five proton therapy centers treating patients and over 2300 x-ray based linear accelerator facilities. Limiting the widespread application of proton radiotherapy to the general cancer patient community is the capital, building and operating costs associated with proton radiotherapy that exceed $100 million per site, a substantial cost differential with x-ray based facilities. A compelling approach is to combine the physical advantages of proton therapy into a smaller, cheaper, gantry-mounted or fixed line system that can be widely disseminated for improved radiotherapy. The development and investigation of such an approach using coaxial plasma proton acceleration, is described in this proposal. Recent breakthroughs in the understanding and stabilization of a special high-velocity mode of operation in plasma accelerators by the Plasma Physics Laboratory at Stanford University have lead to an accelerator concept with the potential to make affordable, compact proton therapy possible. The aims for this feasibility study are to develop the existing accelerator to: 1. Testing and beam characterization: This task includes the use of various optical diagnostics and the measurements of phase space properties using a magnetic sector energy spectrometer. Nuclear track detection is used as a contingency to characterize the beam over a wide range of operating conditions. 2. Increase plasma accelerator beam energy: This task consists of optimization and scaling of various parameters, such as electrode shapes and dimensions, electric circuit parameters, mass flow, and power supply voltage. This task also includes the development of a new hydrogen injection system. 3. Modeling of beam dynamics: The feasibility of using a compact magnet/collimator assembly for energy dispersion and selection is assessed using the Geant4 software. The goal is to study approaches for beam transport and collimation while minimizing and capturing harmful secondary radiation and neutrons. The long term goal of this project is to develop the next generation of proton therapy treatment units that will improve human health through the wide dissemination of a compact, single room, proton therapy treatment system. PUBLIC HEALTH RELEVANCE: This proposal describes a high-impact, high risk development combining exciting cutting edge developments in accelerator technology in mechanical engineering at Stanford University with an important unmet need in radiation oncology- a relatively compact, inexpensive accelerator for proton therapy. The long term goal of this project is to develop the next generation of proton therapy treatment units that will improve human health of cancer patients by the wide dissemination of a small, single room, proton therapy treatment system that will allow increased access to this improved treatment modality.