Four-Dimensional Monte Carlo Dose Calculation

四维蒙特卡罗剂量计算

• 批准号: 7394459
• 负责人: HARALD PAGANETTI
• 金额: $ 24.97万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7394459
• 关键词: Abdomen; Accounting; Address; Adopted; Affect; Algorithms; Anatomy; Area; Blur; Breathing; Chest; Classification; Clinical; Code; Collimator; Color; Complex; Computers; Condition; Data; Data Set; Dependency; Deposition; Depth; Dose; Dose-Rate; Event; Extravasation; Eye; Failure; Four-dimensional; Goals; Head; Image; Individual; Lead; Left; Light; Lung; Malignant neoplasm of lung; Maps; Measurement; Methods; Microscopic; Modality; Modeling; Monte Carlo Method; Motion; Numbers; Organ; Patients; Pattern; Personal Satisfaction; Phase; Photons; Plant Leaves; Positioning Attribute; Probability; Procedures; Process; Property; Protons; Publishing; Radiation therapy; Randomized; Recording of previous events; Relative (related person); Reporting; Resolution; Respiration; Rotation; Running; Safety; Scanning; Signal Transduction; Simulate; Site; Slide; Speed; Staging; Statistical Models; Structure; Structure of parenchyma of lung; System; Techniques; Thoracic Neoplasms; Time; Time Study; Tissues; Tongue; Translating; Tumor Volume; Variant; Water; Work; attenuation; base; cancer therapy; density; experience; heart motion; image registration; imaging Segmentation; innovation; neurosurgery; novel; programs; proton beam; simulation; size; tool; treatment planning; tumor; two-dimensional

DESCRIPTION (provided by applicant): To study dosimetric effects in time-dependent geometries the results of individual three-dimensional (3D) calculations are usually added or statistically combined. This is cumbersome if the geometry is complex, if high time resolution is envisaged (e.g. considering dose rate), or if the microscopic volume displacement as a function of time is not known. Furthermore, it is difficult to study double-dynamic systems to investigate the influence of time-dependent beam delivery (moving leafs in a multi-leaf collimator) on the dose deposition in a moving target (organ motion or deformation). Here, 4D instead of multiple 3D calculations are required. Monte Carlo (MC) simulations are believed to be the most accurate tool for dose calculation and wiII presumably have the biggest impact in areas of large density variations, e.g. for lung cancer treatments. Interestingly, this is also the area where we might expect the biggest impact of organ motion on the dose distribution. The MC method is well suited to study dosimetric effects of motion with high accuracy. However, until now, like for analytical dose calculation techniques, the geometric information cannot be modified during the simulation. This limits applications to multiple 3D instead of true 4D. In taking advantage of objejctoriented C++ programming techniques we are proposing true 4D MC dose calculation. Local dose deposition in the patient will be calculated while beam configuration and organ geometry are changed continuously MLC leaf positions will be changing during the simulation according to leaf sequencing files. Based on deformable image registration we will track microscopic areas based on the patient's CT during the dose calculation. 4D dose calculation will allow the usage of a preset moving pattern based on clinical experience or patient specific 4D CT information. The capability of studying time dependent geometries and the interplay in double-dynamic systems for any time scale based on treatment head variations and patient's breathing pattern will take MC dose calculation to a new level, to the level of 4D treatment simulation.

描述（由申请人提供）：为了研究随时间变化的几何形状的剂量效应，通常将各个三维（3D）计算的结果相加或统计组合。 如果几何形状复杂，如果设想高时间分辨率（例如考虑剂量率），或者如果作为时间函数的微观体积位移未知，则这会很麻烦。 此外，研究双动态系统来研究时间依赖性光束传输（多叶准直器中的移动叶片）对移动目标（器官运动或变形）中剂量沉积的影响是很困难的。 这里需要4D而不是多个3D计算。 蒙特卡罗 (MC) 模拟被认为是最准确的剂量计算工具，并且可能对密度变化较大的区域产生最大影响，例如，用于肺癌治疗。 有趣的是，这也是我们预计器官运动对剂量分布影响最大的区域。 MC 方法非常适合高精度地研究运动的剂量效应。 然而，到目前为止，与分析剂量计算技术一样，几何信息在模拟过程中无法修改。 这将应用限制为多个 3D，而不是真正的 4D。 通过利用面向对象的 C++ 编程技术，我们提出了真正的 4D MC 剂量计算。 将计算患者体内的局部剂量沉积，同时连续改变光束配置和器官几何形状 MLC 叶片位置将在模拟过程中根据叶片测序文件发生变化。 基于可变形图像配准，我们将在剂量计算期间根据患者的 CT 跟踪微观区域。 4D 剂量计算将允许使用基于临床经验或患者特定 4D CT 信息的预设移动模式。 基于治疗头变化和患者呼吸模式研究任何时间尺度的时间依赖性几何形状和双动态系统相互作用的能力将把 MC 剂量计算提升到一个新的水平，达到 4D 治疗模拟的水平。