Lung Sparing for SBRT with beam's-eye-view images and real time tumor tracking

描述（由申请人提供）：在美国，死于肺癌的人比死于前列腺癌、乳腺癌、结肠癌和直肠癌的人加起来还要多。2009年，美国估计有187,000人被诊断为非小细胞肺癌（NSCLC），其中超过37,000人表现为局部或早期疾病。随着早期检测方法的改进和更广泛的传播，这一比例预计还会增加。立体定向全身放射治疗（SBRT）已被证明对早期肺癌患者提供良好的局部控制（85%-95%）。然而，最近的一项II期研究发现，3级或更高的毒性在很大一部分患者中，特别是那些位于中心位置的肿瘤。研究表明，减少SBRT切缘可以显著降低正常组织并发症的发生概率。随着SBRT越来越多地成为早期局限性非小细胞肺癌的治疗选择，减少有害副作用变得越来越重要。我们正在提出一种新的故障安全技术，以减少毒性，同时保留对不断增长的患者群体的局部控制。我们的假设是，在SBRT期间，使用光束眼视图（BEV）成像和动态多叶准直仪（DMLC）直接跟踪肺肿瘤，将导致临床上显著的正常组织保留。目前的建议是第一个采用先进的多模板无标记BEV跟踪算法来获得DMLC递送的实时肿瘤位置。无标记的多模板创新的临床益处包括：1)自动选择相关标志，2)在变形、旋转和部分遮挡时连续跟踪，3)患者无需额外的成像剂量，4)整个肿瘤的直接成像，5)无需侵入性基底植入和相关的不良反应。这比以前的技术有了很大的改进。该治疗优势将在临床条件下的拟人化幻体系统中进行实验量化。最终的结果将是一个集成的实时目标跟踪和动态传递系统，用于放射治疗以及量化预期的临床效益。与DMLC跟踪的临床整合是一个具有挑战性的工程问题，对大规模的人类健康具有可衡量的积极影响。该项目很好地体现了NIBIB支持物理科学和工程研究与开发以改善人类健康的理想。

DESCRIPTION (provided by applicant): More people in the U.S. die from lung cancer than from prostate, breast, colon and rectum cancers combined. Of the estimated 187,000 people in the U.S. who were diagnosed with non-small cell lung cancer (NSCLC) in 2009, over 37,000 of them presented with localized or early stage disease. This fraction is expected to grow as methods of early detection improve and become more widely disseminated. Stereotactic body radiation therapy (SBRT) has been shown to provide excellent local control (85%-95%) for early-stage lung cancer patients. However, a recent phase II study found Grade 3 or greater toxicities in a significant fraction of the patients, particularly those with centrally located tumors. Studies have shown that decreases in SBRT margins can significantly reduce the probability of normal tissue complications. As SBRT is increasingly becoming the therapy of choice for early-stage, localized non-small cell lung cancer, reducing the harmful side effects becomes increasingly important. We are proposing a novel failsafe technology to reduce toxicity while retaining local control for this growing population of patients. Our hypothesis is that tracking lung tumors directly during SBRT, using beam's-eye-view (BEV) imaging coupled with a dynamic multileaf collimator (DMLC), will lead to clinically significant normal tissue sparing. The current proposal is the first to employ an advanced multi- template marker-less BEV tracking algorithm to derive the real-time tumor location for DMLC delivery. Clinical benefits of the multi-template marker-less innovation include 1) automatic selection of relevant landmarks, 2) continuous tracking during deformations, rotations and partial obscurations, 3) no additional imaging dose to the patient, 4) direct imaging of the entire tumor, and 5) no need for invasive fiducial implantations and the associated adverse effects. This represents a substantial improvement over previous techniques. The therapeutic advantage will be quantified experimentally in an anthropomorphic phantom system under clinical conditions. The end result will be an integrated real-time target tracking and dynamic delivery system for radiation therapy as well as quantification of the anticipated clinical benefits. Clinical integration with the DMLC tracking is a challenging engineering problem with a measurable positive impact on human health on a large scale. This project represents well the ideals of the NIBIB to support research and development in the physical sciences and engineering for the improvement of human health.