Combined radiation acoustics and ultrasound imaging for real-time guidance in radiotherapy

放射治疗对许多类型的癌症都是非常有效的治疗方法。实现ITS的主要障碍 完全治愈承诺是目前的治疗过程，通常情况下，最初计划的肿瘤区域会暴露出来。 到固定的电离辐射模式，而与目标变形、器官运动或功能无关。至 避免遗漏，通过增加规划来处理该前馈过程中的几何不确定性 肿瘤周围的边缘，但必然会导致不必要的非受累组织暴露，这可能会导致 致衰弱的毒物。我们假设，对正常组织的有害辐射剂量可能显著 通过使用“知道”肿瘤的形状和位置以及位置的反馈系统来减少 以及分娩过程中照射剂量的强度。这个框架将需要独特的能力来 在放射治疗期间同时成像吸收剂量和靶向肿瘤解剖，这不是 利用目前的现有技术是可能的。 辐射物理学中的一个已知现象是由于热膨胀而产生声波 穿透性辐射吸收后的物质。该辐射感生声信号的检测 从临床治疗来看，BEAM最近已被证实，但尚未在临床上实现。那个信号 作为治疗光束的结果，它实时“免费”地存在。信号可以用以下方式测量 超声探测器和处理，以显示沉积的能量/剂量的位置和强度。 此外，超声波技术也早已被建立用于医学成像和监测 肿瘤的大小、形状和位置，不引入电离辐射。 因此，我们建议将辐射声学测量和超声成像结合在一起 集成系统，使用先进的矩阵阵列探头，实时确定体积输送 与当天肿瘤形状和位置有关的辐射剂量，并最终通过 在线反馈。该系统将在幻影和临床前模型中进行优化。然后，它的可行性和 多功能性将被测试用于治疗肝脏和胰腺肿瘤，这两个侵袭性癌症部位 由于变形和生理运动而导致的剂量错位不仅影响肿瘤的根除，而且还 影响患者的生命功能和随后的治疗结果。 影响声明：我们的目标是为在线实施新的、安全、简单、经济高效的技术和方法 可同时提供肿瘤追踪和剂量补偿的放射治疗指导 能力。这些技术将在肝癌和胰腺癌的试点临床研究中进行评估，以 展示翻译的可行性和潜力。如果成功，这种反馈技术将有一个 对个性化放射治疗和实现最佳治疗结果产生重大影响。

Radiotherapy can be a highly effective treatment for many types of cancers. A major impediment to achieving its full curative promise is the current delivery process, where typically the originally planned tumor area is exposed to a fixed pattern of ionizing radiation over time irrespective of target deformations, organ motion, or function. To avoid misses, geometric uncertainties in this feedforward process are dealt with by increasing the planning margin around the tumor, but of necessity result in unnecessary exposure of uninvolved tissue which can lead to debilitating toxicities. We hypothesize that the unwanted radiation dose to normal tissues could be significantly reduced by using a feedback system that would “know” the shape and location of the tumor as well as the location and intensity of the irradiated dose during delivery. This framework would require the unique ability to simultaneously image the absorbed dose and the targeted tumor anatomy during radiation delivery, which is not possible with currently existing technologies. A known phenomenon in radiation physics is the generation of acoustic waves due to thermal expansion of a substance following the absorption of penetrating radiation. Detection of this radiation induced acoustic signal from clinical treatment beams has been recently demonstrated but has not been clinically realized. That signal exists “for free” in real time as a consequence of the treatment beam. The signal can be measured with ultrasound detectors and processed to reveal the location and intensity of the deposited energy/dose. Furthermore, ultrasound technologies have also long been established for medical imaging and monitoring of tumor size, shape and location, without introducing ionizing radiation. Therefore, we propose to combine measurements of radiation acoustics and ultrasound imaging in an integrated system using advanced matrix array probes to determine in real-time the volumetric delivered radiation dose with respect to that day’s tumor shape and location, and ultimately to optimize tumor targeting via online feedback. The system will be optimized in phantoms and preclinical models. Then, its feasibility and versatility will be tested for treatment of tumors in the liver and the pancreas, two aggressive cancer sites where misplaced dose due to deformation and physiological motion not only compromises tumor eradication but also affects vital functions in the patient and subsequent treatment outcomes. Impact statement: We aim to implement new, safe, simple, cost effective technology and methods for online guidance of radiotherapy delivery that can provide simultaneous tumor tracking and dose compensation capabilities. These technologies will be evaluated in a pilot clinical study of liver and pancreatic cancers to demonstrate feasibility and potentials for translation. If successful, this feedback technology will have a significant impact on personalizing radiotherapy delivery and achieving optimal treatment outcomes.