Quantitative dual-energy CT imaging for radiation therapy treatment planning

用于放射治疗计划的定量双能 CT 成像

• 批准号: 8105671
• 负责人: JEFFREY F WILLIAMSON
• 金额: $ 34.85万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8105671
• 关键词: Address; Algorithms; Architecture; Base Composition; Benchmarking; Biological; Brachytherapy; Breast; Cancer Patient; Charge; Chest; Clinical; Clinical Research; Clinical Treatment; Clinical assessments; Code; Data; Data Set; Dependence; Development; Devices; Disease; Dose; Electron Beam; Electron Beam Therapy; Environment; Equilibrium; Female breast; Funding; Goals; Head and Neck Cancer; Head and neck structure; Housing; Image; Imaging technology; Implant; Intensity-Modulated Radiotherapy; Knowledge; Light; Lung; Malignant neoplasm of lung; Malignant neoplasm of prostate; Maps; Measurement; Medical; Methods; Modality; Modeling; Noise; Normal tissue morphology; Organ; Outcome; Patients; Pelvis; Performance; Photons; Process; Property; Prostate; Protons; Radiation therapy; Relative (related person); Research; Resolution; Sampling; Scanning; Seeds; Shapes; Simulate; Slice; Structure; System; Techniques; Technology; Testing; Therapeutic; Tissues; Tomography, Computed, Scanners; Toxic effect; Uncertainty; Variant; Work; X-Ray Computed Tomography; abstracting; analytical tool; base; cancer site; clinical practice; clinically significant; cost effective; density; digital; electron density; experience; high risk; human tissue; image reconstruction; improved; in vivo; innovation; irradiation; male; malignant breast neoplasm; novel; parallel computer; particle; patient population; proton beam; prototype; reconstruction; therapy outcome; tool; treatment planning; tumor

DESCRIPTION (provided by applicant): Quantitative dual-energy CT imaging for radiation therapy treatment planning 6. Project Summary/Abstract Proton-beam therapy (PT) and low-energy (20-60 keV) photon-emitting brachytherapy (LEPBT) are rapidly evolving modalities with high potential for improving radiation therapy clinical outcomes because of their ability to deliver high doses to the target tissue while sparing surrounding normal tissues. Dose delivery from both modalities is sensitive to the atomic composition as well as election density of the irradiated tissues. For LEPBT, current dose-calculation practice ignores tissue inhomogeneity, introducing dose-prediction errors as large as a factor of 2. For PT, current quantitative single-energy computed tomography imaging (QSECT) leads to 3-6 mm range uncertainties that significantly increases exposure of adjacent organs to high doses. Recommended bulk tissue compositions are based upon inadequate data with large and essentially unknown patient-to-patient and intrapatient variability and cannot provide an adequate basis either for clinical treatment planning or assessing dose delivery uncertainty in PT or LEPBT. Conventional QSECT is inadequate for quantitative study of PT and LEPBT radiological tissue properties because tissue composition and electron density vary independently. The goal of this project is to develop and validate a novel quantitative dual-energy CT (QDECT) imaging technology able to accurately image the radiological properties and to demonstrate QDECT utility by assessing the magnitude and clinical significance of tissue inhomogeneities in a small patient sample. To achieve these goals, three specific aims are proposed. In Specific Aim 1, a novel statistical image reconstruction algorithm will be developed for reconstructing 3D cross-section maps derived from dual energy spiral sinograms exported from a clinical multi-slice CT imaging system. Specifically, an alternating minimization regularized, 3D reconstruction engine will be adapted and optimized to the problems of accurate tissue-map imaging for brachytherapy and proton-beam dose planning and a clinical prototype implemented. In Specific Aim 2, QDECT cross-section images reconstructed from experimentally-acquired dual-energy sinograms will be validated against experimental phantom, patient data, and computational benchmarks. Analysis of estimation errors will be used to focus AM reconstruction algorithm optimization efforts above. The developed QDECT process will be used to study the magnitude and variability of proton stopping-power and photon-cross section maps in our small patient population. Specific Aim 3 will study the dosimetric and clinical impact of more accurate patient-specific QDECT cross-section distributions on simulated brachytherapy, electron-beam and proton-beam treatment plans in head and neck, prostate, breast, and lung cancer sites using available treatment-planning systems and Monte Carlo dose-estimation codes. PUBLIC HEALTH RELEVANCE: The therapeutic advantage of exit-dose free proton-therapy over competing modalities such as megavoltage photon intensity-modulated radiation therapy (IMRT) is partially negated because of the large target volume margins needed to compensate for 3-6 mm range uncertainties. By reducing such range uncertainties to 1 mm, our quantitative cross-section imaging project will make proton-therapy high dose critical structure sparing competitive with IMRT, greatly enhancing its potential for improving clinical outcomes. For low-energy photon brachytherapy (LEPBT) of localized prostate cancer and accelerated partial breast irradiation, our project will reduce 10%-30% dose uncertainties to 5%, enabling dose escalation in higher risk disease without increasing toxicity and objective comparison with other radiation therapy modalities to be realized.

描述（由申请人提供）：用于放射治疗计划的定量双能量CT成像6。项目摘要/摘要质子束治疗（PT）和低能量（20-60 keV）光子发射近距离放射治疗（LEPBT）是快速发展的模式，具有改善放射治疗临床结局的高潜力，因为它们能够向靶组织输送高剂量，同时保留周围正常组织。从这两种方式的剂量输送是敏感的原子组成，以及电子密度的照射组织。对于LEPBT，目前的剂量计算实践忽略了组织的不均匀性，引入了高达2倍的剂量预测误差。对于PT，目前的定量单能量计算机断层扫描成像（QSECT）导致3-6 mm范围的不确定性，显著增加了邻近器官对高剂量的暴露。推荐的大块组织成分基于不充分的数据，患者间和患者内变异性较大且基本未知，无法为临床治疗计划或评估PT或LEPBT中的剂量输送不确定性提供充分的依据。常规QSECT不足以定量研究PT和LEPBT放射组织特性，因为组织成分和电子密度独立变化。本项目的目标是开发和验证一种新型定量双能CT（QDECT）成像技术，该技术能够准确成像放射学特性，并通过评估小样本患者中组织不均匀性的大小和临床意义来证明QDECT的实用性。 为了实现这些目标，提出了三个具体目标。在特定目标1中，将开发一种新的统计图像重建算法，用于重建从临床多层CT成像系统导出的双能量螺旋正弦图导出的3D横截面图。具体而言，交替最小化正则化，3D重建引擎将适应和优化的问题，准确的组织地图成像的近距离放射治疗和质子束剂量规划和临床原型的实施。在特定目标2中，将根据实验体模、患者数据和计算基准对从实验采集的双能量正弦图重建的QDECT横截面图像进行确认。估计误差的分析将用于集中上述AM重建算法优化工作。所开发的QDECT过程将用于研究我们的小患者人群中质子阻止功率和光子截面图的幅度和可变性。具体目标3将研究更准确的患者特异性QDECT横截面分布对使用可用治疗计划系统和蒙特卡罗剂量估计代码的头颈部、前列腺、乳腺和肺癌部位的模拟近距离放射治疗、电子束和质子束治疗计划的剂量测定和临床影响。 公共卫生相关性：无出射剂量质子治疗相对于竞争模式（例如兆伏光子强度调制放射治疗（IMRT））的治疗优势被部分否定，因为需要大的靶体积裕度来补偿3-6 mm范围的不确定性。通过将这种范围不确定性降低到1 mm，我们的定量截面成像项目将使质子治疗高剂量关键结构保留与IMRT竞争，大大提高其改善临床结果的潜力。对于局限性前列腺癌和加速部分乳腺照射的低能量光子近距离治疗（LEPBT），我们的项目将使10%-30%的剂量不确定性降低到5%，从而实现在不增加毒性的情况下在较高风险疾病中进行剂量递增，并与其他放射治疗方式进行客观比较。