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

描述(申请人提供)：部分器官运动是最大限度地利用现代前列腺调强放射治疗(IMRT)或容量调制放射治疗(VMAT)的主要限制因素。在低分割治疗中，由于长时间的剂量输送，器官运动的不利影响进一步加剧。在这个项目中，我们将开发一种结合mV和kV成像的实时基准跟踪策略，以解决部分内前列腺运动的问题。这项工作的基本假设是，实时图像引导的前列腺放射治疗将大大减少射束靶向的不确定性，并提供显著改善的剂量分布，以实现更好的局部肿瘤控制，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)完善用于调强放射治疗和VMAT的MV/kV混合图像采集协议；(2)通过先导性临床研究评估混合图像引导技术的潜在临床影响。这项研究的成功完成将为放射肿瘤学学科提供治疗前列腺癌的迫切需要的手段，并为我们使用调强放疗/VMAT安全可靠地增加辐射剂量提供强有力的方法。鉴于其以最佳方式迎合内部不确定因素的重大承诺，该项目的成功完成应该会大大改善前列腺癌患者的护理。 公共卫生相关性：在目前的前列腺调强放射治疗(IMRT)或体积调制放射治疗(VMAT)中，通过引入较大的PTV裕度来补偿部分内前列腺运动的不良影响，这会导致邻近关键器官的照射，并限制前列腺剂量的增加。为了快速将先前开发的千伏/毫伏实时肿瘤跟踪技术应用到常规临床实践中，在R21应用中，我们计划对前列腺癌放射治疗的实时图像引导策略的有效性和临床潜力进行一系列评估。这项研究的成功完成将为前列腺癌的治疗提供一种急需的手段，并为我们使用调强放疗安全可靠地增加放射剂量提供一种强有力的方法。

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.