Clinical Evaluation of Real-Time MV/kV Image Guided Prostate Radiation Therapy

描述（由申请人提供）：分数阶内器官运动是现代前列腺调强放射治疗（IMRT）或体积调制放射治疗（VMAT）最大限度利用的主要限制因素。在低分割治疗中，由于给药时间过长，器官运动的不良影响进一步加剧。在这个项目中，我们将开发一种实时基准跟踪策略，使用组合MV和kV成像来解决前列腺在分数段内运动的问题。这项工作的基本假设是，实时图像引导前列腺放射治疗将大大减少光束靶向的不确定性，并提供显著改善的剂量分布，以实现更大的局部肿瘤控制，同时减少正常组织并发症的可能性。该项目的具体目标是：(1)完善用于IMRT和VMAT的混合MV/kV图像采集协议；(2)通过临床试点研究，评估混合图像引导技术的潜在临床影响。本研究的成功完成将为放射肿瘤学提供治疗前列腺癌急需的手段，并为我们安全可靠地使用IMRT/VMAT提高放射剂量提供有力途径。鉴于该项目对优化部分不确定性的重大承诺，该项目的成功完成将导致前列腺癌患者护理的实质性改善。

DESCRIPTION (provided by applicant): Intra-fractional organ motion is a predominant limiting factor for the maximum exploitation of modern prostate intensity modulated radiation therapy (IMRT) or volumetric modulated radiation therapy (VMAT). Adverse influence of the organ motion is further aggravated in hypofractionated treatment because of protracted dose delivery. In this project we will develop a real-time fiducial tracking strategy using a combined MV and kV imaging to solve the problem of intra-fraction prostate movement. The underlying hypothesis of this work is that real-time image guided prostate radiation therapy will greatly reduce the uncertainty in beam targeting and provide substantially improved dose distributions required to achieve greater local tumor control while reducing the probability of normal tissue complications. Specific aims of the project are to (1) Refine a hybrid MV/kV image acquisition protocol for IMRT and VMAT; (2) Evaluate the potential clinical impact of the hybrid image guidance technique through a pilot clinical study. Successful completion of this investigation will provide radiation oncology discipline a critically needed means to treat prostate cancer, and afford a powerful way for us to safely and reliably escalate the radiation dose using IMRT/VMAT. Given its significant promise to optimally cater for intra-fractional uncertainties, successful completion of the project should lead to substantial improvement in prostate cancer patient care. PUBLIC HEALTH RELEVANCE: In current prostate intensity modulated radiation therapy (IMRT) or volumetric modulated radiation therapy (VMAT), the adverse effect of intra-fractional prostate motion is compensated by introducing a large PTV margin, which leads to irradiation of adjacent critical organs and limits the prostate dose escalation. With the goal of rapidly deploying a previously developed kV/MV real-time tumor tracking technique into routine clinical practice, in this R21 application we plan to conduct a series of evaluations of the efficacy and clinical potential of the real-time image guidance strategy for prostate radiation therapy. Successful completion of this investigation will provide a critically needed means for treating prostate cancer and afford a powerful way for us to safely and reliably escalate radiation dose using IMRT.