Feedback Control of Respiration Induced Tumor Motion with a Treatment Couch

描述（由申请人提供）：呼吸引起的肿瘤运动导致放射治疗计划和交付的不准确。这对于高适形治疗，如调强放射治疗（IMRT）和立体定向放射治疗（SBRT）尤其重要。传统的解决方案包括在肿瘤周围增加“安全边界”，这通常会导致对正常组织的不必要照射，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。我们建议开发一种使用治疗床的新型肿瘤运动补偿系统，该系统将确保准确地提供放射治疗，而不会增加不适或治疗时间，也不会降低生物有效性。本提案的目标是利用反馈控制开发一种实时运动同步治疗沙发系统。该提案的具体目标是：1)在正常呼吸过程中，使用电影MR对肿瘤进行动态成像，同时使用红外相机对皮肤标记物进行成像；2)开发一个推理模型，将皮肤标记物的位置与肿瘤位置相关联，使用偏最小二乘法（PLS）回归；3)设计和测试一个治疗沙发和控制系统，该系统将使用反馈控制来补偿呼吸引起的运动。4)利用自回归建模提前预测肿瘤位置，通过克服系统中的死时间和自适应滤波来识别不规则肿瘤位置，提高反馈控制系统的性能。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。提出的研究工作将导致使用实时运动同步治疗沙发的新型运动管理框架的发展。它最终在临床实践中实施，将通过使用更小的肿瘤边缘和准确的肿瘤运动补偿来降低正常组织的毒性。这将使高适形治疗如调强放射治疗（IMRT）和立体定向体放射治疗（SBRT）以可靠的方式得到更广泛的应用。

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.