Protoacoustics - Clinical based range verification for Cancer Treatment

项目摘要 在放射治疗中，用电离辐射靶向癌症肿瘤，电离辐射通过以下方式诱导细胞死亡： 破坏DNA辐射影响恶性和健康组织，治疗计划力求 向肿瘤提供致命的辐射剂量，同时最大限度地减少对周围环境的附带损害 组织.虽然标准治疗采用光子辐射，但质子放射治疗的临床使用 由于其局部剂量的能力而增加。与光子相比， 沉积随穿透深度呈指数下降，质子存款的大部分 由于远端急剧下降，它们的能量在其路径的最后几mm中被吸收。局部能量 沉积峰被称为布拉格峰。由于峰值沉积曲线，组织 在目标区域接收到与光子相比更低的相对剂量之前和之后 治疗穿透深度取决于质子的初始动能和 受照射材料的阻止能力。 质子放射治疗癌症的主要优点是质子布拉格峰。 与光子和电子不同的是，有限的范围和在远端处的急剧剂量下降， 质子束的布拉格峰增加了我们使治疗剂量符合肿瘤的能力， 保留周围的健康组织（Knopf和Lomax，2013）。但有 我们精确定位质子束布拉格峰及其远端剂量的能力的不确定性 患者体内的梯度，这通常会导致射束的故意过冲和欠冲 转移到位于肿瘤前方和后方的健康组织中。这一大幅度增加， 边缘破坏了质子独特的陡峭剂量梯度的好处， 质子放射治疗的临床潜力。 为了充分利用质子布拉格峰的优点，迫切需要减少 质子束范围的不确定性，特别是在远侧边缘， 存在（Knopf和Lomax，2013）。PET成像和即时伽马技术已经被 提出并测试了现场范围核查技术，但它们缺乏准确性， 复杂性和成本促使研究人员探索其他方法。原声学 测量质子束产生的声波，是一个未开发的，潜在的现场 距离验证技术

Project Summary In radiation therapy, cancer tumors are targeted with ionizing radiation that induces cell death by damaging DNA. Radiation affects malignant and healthy tissue, and treatment plans strive to deliver a lethal radiation dose to tumors while minimizing collateral damage to surrounding tissue. While standard therapy employs photon radiation, the clinical use of proton radiotherapy is increasing because of its ability to localize dose. Compared to photons, which display an exponential decrease in deposition with penetration depth, protons deposit a large fraction of their energy in the last few mm of their path due to the sharp distal falloff. The localized energy deposition peak is called the Bragg peak. Because of the peaked deposition profile, tissue before and, particularly, after the target region receive a lower relative dose compared to photon treatment. The penetration depth depends on the initial kinetic energy of the protons and the stopping power of the irradiated material. The main advantage of proton radiotherapy for treatment of cancer is the proton Bragg peak. Unlike photons and electrons, the finite range and the sharp dose falloff at the distal end of the proton beam's Bragg peak increases our ability to conform the treatment dose to the tumor and spare the surrounding healthy tissues (Knopf and Lomax, 2013). However, there are uncertainties in our ability to precisely locate the proton beam Bragg peak and its distal dose gradient within the patient, which often results in a deliberate over- and undershoot of the beam into healthy tissues located in front of and beyond the tumor. This substantial increase to the margins undermines the benefits of the proton's unique steep dose gradient, reducing the clinical potential of proton radiotherapy. To fully exploit the advantages of the proton Bragg peak, there is a critical need to reduce proton beam range uncertainties especially at the distal edge where a sharp dose gradient exists (Knopf and Lomax, 2013). PET imaging and prompt gamma techniques have been proposed and tested as in situ range verification techniques, but their lack of accuracy, complexity, and cost have motivated researchers to explore other methods. Protoacoustics, the measurement of sound waves generated by proton beams, is an undeveloped, potential in situ range verification technique.