Evaluation of tumor motion management strategies in radiotherapy using 4D-MRI

使用 4D-MRI 评估放射治疗中的肿瘤运动管理策略

• 批准号: 8697027
• 负责人: Russell Hales
• 金额: $ 23.28万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-05 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8697027
• 关键词: 4D Imaging; Abdomen; Accounting; Address; Anatomy; Breast; Breathing; Cancer Patient; Chest; Clinic; Clinical; Complex; Disorder by Site; Dose; Dose-Limiting; Effectiveness; Evaluation; Future; Goals; Image; Image Analysis; Imaging Device; Imaging Techniques; Imaging technology; Individual; Liver; Location; Lung; Magnetic Resonance Imaging; Malignant neoplasm of abdomen; Malignant neoplasm of lung; Malignant neoplasm of thorax; Methods; Motion; Movement; Normal tissue morphology; Organ; Pancreas; Patients; Pattern; Phase; Play; Positioning Attribute; Prostate; Radiation; Radiation therapy; Research; Resolution; Respiration; Respiratory Diaphragm; Role; Scanning; Sensitivity and Specificity; Skin; Slice; Solutions; Surrogate Markers; Techniques; Testing; Thoracic Neoplasms; Time; Toxic effect; Uncertainty; Variant; X-Ray Computed Tomography; base; cancer radiation therapy; cohort; image processing; imaging modality; novel; prevent; public health relevance; reconstruction; respiratory; soft tissue; tool; tumor

DESCRIPTION (provided by applicant): Involuntary and voluntary patient motion is a major obstacle for achieving high-precision radiation therapy of cancers especially in the thorax and upper abdomen. As the target is continuously moving, an additional margin has to be added to the clinical target volume to compensate for the uncertainty caused by the respiration-induced organ motion, causing unnecessary toxicity to the normal tissue and limiting the dose delivered to the target. Due to the lack of reliable and safe direct tumor tracking methods, surrogates are commonly used in clinics to compensate for the tumor motion during radiotherapy. However, the relationship between the surrogate and tumor motion cannot be generalized as it depends on individual patients, tumor location, and treatment fractions. Therefore, our understanding of the correlation between the surrogate and the actual intrafraction tumor motion due to respiration is very limited. Although 4D-CT image is typically used for the radiotherapy motion assessment and planning, it is an oversimplified snapshot representation of a single-breathing cycle and is inherently limited by radiation dose. Consequently, these limitations prevent applicability in acquiring information over timescales that represent a treatment session. Advances in dynamic MRI present opportunities for the pre-treatment radiotherapy setting that have yet to be systematically harnessed. MRI is highly advantageous as it is non-ionizing and provides excellent soft tissue contrast. Variations in respiratory motion can be captured by imaging over longer durations or more frequently. MRI also achieves faster frame rates than 4D-CT, which likely provides a more accurate description of the moving anatomy. In this study, we will use dynamic MRI techniques to characterize tumor motion as well as surrogates used for predicting tumor motion. By way of this research, we will fully characterize patient-specific respiration- induced tumor motion and evaluate the accuracy and effectiveness of surrogate-based motion management strategies currently used in radiotherapy. Specifically, 4D-MRI obtained over a temporal duration consistent with radiotherapy treatments will provide spatio-temporal information of both the tumor and surrogate, and therefore can serve as a means to assess the quality of the tumor motion tracking with the surrogate, suggesting an appropriate motion management strategy for individual patients. The proposed methods will have general applicability to both thoracic and abdominal sites of disease. We intend that this research will be ground breaking and, if so, will likely result in a change of practice in radiotherapy, benefiting innumerable thoracic and abdominal cancer patients in the future.

描述（由申请人提供）：非自愿和自愿的患者运动是实现癌症高精度放射疗法的主要障碍，尤其是在胸腔和上腹部。随着目标的连续移动，必须在临床目标体积中添加一个额外的边距，以补偿由呼吸引起的器官运动引起的不确定性，从而导致对正常组织的不必要的毒性并限制剂量输送到目标。由于缺乏可靠且安全的直接肿瘤跟踪方法，替代物通常在诊所中用于补偿放射治疗期间肿瘤运动。然而，替代物和肿瘤运动之间的关系不能推广，因为它取决于单个患者，肿瘤位置和治疗部分。因此，我们对替代物与呼吸造成的实际术中肿瘤运动之间的相关性的理解非常有限。尽管通常将4D-CT图像用于放射疗法的运动评估和计划，但它是单呼吸周期的过度简单快照表示，并且本质上受辐射剂量的限制。因此，这些限制阻止了根据代表治疗课程的时间尺度获取信息的适用性。动态MRI的进展为尚未系统利用的预处理放射治疗设置的机会提供了机会。 MRI是有利的，因为它是非电源化的，并且提供了出色的软组织对比度。呼吸运动的变化可以通过在更长的持续时间或更频繁的时间内成像来捕获。 MRI还达到了比4D-CT更快的帧速率，这可能会更准确地描述移动解剖结构。在这项研究中，我们将使用动态MRI技术来表征肿瘤运动以及用于预测肿瘤运动的替代物。通过这项研究，我们将充分表征患者特异性呼吸诱导的肿瘤运动，并评估当前用于放射疗法的基于替代运动的运动管理策略的准确性和有效性。具体而言，在与放射治疗一致的时间持续时间内获得的4D-MRI将为肿瘤和替代物提供时空信息，因此可以用作评估具有替代物的肿瘤运动跟踪质量的手段，并建议对个别患者制定适当的运动管理策略。所提出的方法将对疾病的胸部和腹部部位具有一般适用性。我们打算这项研究将是 突破性的破裂，如果是这样，可能会导致放射疗法的实践改变，从而使无数胸腔和腹部癌症患者受益。