Feedback Control and Inferential Modeling for Radiotherapy Treatment Couch

描述（由申请人提供）：呼吸引起的肿瘤运动会导致计算机断层扫描图像上的伪影，并导致放射治疗计划和交付的不准确。传统的解决方案包括在肿瘤周围增加“安全边界”，这通常会导致对正常组织不必要的照射，从而增加正常组织的毒性。目前商业上可用的线性加速器方法包括在辐射输送过程中屏气和门控。前者不能被患者很好地耐受，而后者增加了治疗的传递时间，从而增加了患者虚假运动的风险，甚至降低了所传递辐射的生物有效性。本提案的目标是开发一种使用反馈控制的实时运动同步治疗沙发。本提案的具体目的是：1)设计和测试用于RT传递的呼吸诱导运动同步治疗床的原型的可行性；2)开发一个使用皮肤标记物的推理模型，该模型将使用偏最小二乘法（PLS）模型将其位置与肿瘤运动相关联。为了开发这种治疗沙发，沙发动力学和控制系统将根据患者特定的肿瘤运动轨迹进行建模和测试。一旦原型控制器和沙发的开发完成，将进行完整的系统测试。将开发使用偏最小二乘回归的推理模型，以使用放置在患者皮肤上的运动替代物来预测肿瘤的位置。其稳健性将用多个治疗日获得的呼吸数据进行检验。我们的研究结果有可能对肺癌和上腹部癌症的放射治疗产生重大影响。提出的探索性研究工作将为使用实时运动同步治疗沙发的实时运动管理框架的进一步发展提供基础。它最终在临床实践中的实施将通过使用更小的肿瘤边缘和准确的肿瘤跟踪来降低正常组织的毒性。这将使高适形治疗(如强度调节放射治疗（IMRT）和立体定向体放射治疗（SBRT）（高度不原谅肿瘤运动）以可靠的方式得到更广泛的应用。

DESCRIPTION (provided by applicant): Respiration induced tumor motion causes both artifacts on computed tomography images and leads to inaccuracies in the planning and delivery of radiation therapy treatments. Conventional solutions included adding a "safety margin" around the tumor which can often result in unnecessary irradiation of normal tissue thereby increasing normal tissue toxicity. Current commercially available methods with linear accelerators include breath-holds and gating during radiation delivery. The former is not tolerated well by patients while the later increases treatment delivery time, thereby increasing the risk of spurious patient motion and even reducing the biological effectiveness of the delivered radiation. The goal of this proposal is to develop a real- time motion-synchronized treatment couch using feedback control. The specific aims of this proposal are to 1) design and test the feasibility of a prototype respiration induced motion-synchronized treatment couch for RT delivery and 2) develop an inferential model using skin markers that will correlate their position with tumor motion using partial-least squares (PLS) models. In order to develop this treatment couch, the couch dynamics and control system will be modeled and tested on patient-specific tumor motion trajectories. Once the development of the prototype controller and couch has been completed, a full system test will be performed. Inferential models using partial least squares regression will be developed to predict the position of the tumor using motion surrogates placed on the skin of the patient. Its robustness will be tested with respiration data acquired on multiple treatment days. The results from our proposal have the potential to significantly impact radiation therapy of lung and upper abdominal cancers. The proposed exploratory research effort will provide the foundation for further development of a real-time motion management framework using a real-time motion-synchronized treatment couch. Its eventual implementation in clinical practice will lead to reduced normal tissue toxicity through the use of smaller tumor margins and accurate tumor tracking. This will enable more widespread use of highly conformal treatments such as intensity- modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) (which are highly unforgiving of tumor motion) in a reliable manner.