Feedback Control of Respiration Induced Tumor Motion with a Treatment Couch

描述（由申请方提供）：呼吸诱导的肿瘤运动导致放射治疗计划和实施不准确。这对于高度适形的放射治疗，如调强放射治疗（IMRT）和立体定向体部放射治疗（SBRT）尤其重要。传统的解决方案包括在肿瘤周围增加“安全裕度”，这通常会导致正常组织的不必要的照射，从而增加正常组织的毒性。目前市售的线性加速器方法包括在放射输送期间屏气和门控。前者不能被患者很好地耐受，而后者增加了治疗递送时间，从而增加了伪患者运动的风险，甚至降低了递送的辐射的生物有效性。我们建议开发一种新型的肿瘤运动补偿系统，使用治疗床，将确保准确的放射治疗，而不会增加不适或治疗时间，而不会降低生物学效果。本计画的目标是开发一个使用回馈控制的即时运动同步治疗床系统。该提议的具体目的是1）在正常呼吸期间使用电影MR来对肿瘤进行动态成像，并且使用红外相机来同时对皮肤标记进行成像，2）开发将使用偏最小二乘（PLS）回归将皮肤标记的位置与肿瘤位置相关联的推理模型，3）设计和测试治疗床和控制系统，其将使用反馈控制来补偿呼吸引起的运动，4）采用自回归模型对肿瘤位置进行提前预测，克服系统中的死区，提高反馈控制系统的性能;采用自适应滤波对肿瘤位置进行异常识别。我们提案的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。拟议的研究工作将导致开发一种新的运动管理框架，使用实时运动同步治疗床。其在临床实践中的最终实施将通过使用更小的肿瘤边缘和精确的肿瘤运动补偿来降低正常组织的毒性。这将使得能够以可靠的方式更广泛地使用高度适形的治疗，例如调强放射治疗（IMRT）和立体定向体放射治疗（SBRT）。

DESCRIPTION (provided by applicant): Respiration induced tumor motion leads to inaccuracies in the planning and delivery of radiation therapy treatments. This is particularly important for highly conformal therapies such as intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT). 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. We propose to develop a novel tumor motion compensation system using a treatment couch that will ensure accurate delivery of radiation treatment without increasing discomfort or treatment time and without decreasing the biological effectiveness. The goal of this proposal is to develop a real-time motion-synchronized treatment couch system using feedback control. The specific aims of this proposal are to 1) use cine MR to dynamically image the tumor and an infrared camera to image skin markers simultaneously during normal respiration, 2) develop an inferential model that will correlate the position of the skin markers with the tumor position using partial-least squares (PLS) regression, 3) design and test a treatment couch and control system that will compensate for respiration induced motion using feedback control, 4) use autoregressive modeling to predict the tumor position ahead of time in order to improve the performance of the feedback control system by overcoming the dead time in the system and adaptive filtering to identify anamolous tumor positions. The results from our proposal have the potential to significantly impact radiation therapy of lung and upper abdominal cancers. The proposed research effort will lead to the development of a novel 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 motion compensation. This will enable more widespread use of highly conformal treatments such as intensity- modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) in a reliable manner.