OPTIMIZATION OF ELECTRON ARC DOSE USING DYNAMIC THERAPY

使用动态疗法优化电子弧剂量

• 批准号: 3189846
• 负责人: DENNIS D. LEAVITT
• 金额: $ 8.41万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-02-01 至 1991-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3189846
• 关键词: breast neoplasms; breast surgery; clinical biomedical equipment; computer assisted patient care; computer simulation; drug delivery systems; mathematical model; neoplasm /cancer radiation therapy; patient monitoring device; phantom model; radiation dosage; radiodiagnosis; thermoluminescent radiation detector; thorax

Abstract: The purpose of this work is to investigate the role of dynamic therapy techniques in electron arc therapy. A several year experience with electron arc therapy to the chest wall of women following mastectomy for breast cancer has led to a series of technical and operational modifications in the technique. The experience in over 50 patients has demonstrated the desirability for further optimization of dose distributions across the chest wall, beyond that which we have been able to perform using fixed shape electron collimators. We propose to accomplish this through dynamic movement of the individual vanes of a multi- vane electron collimator during electron arc. The aperture width of each section of the multi-vane collimator will be varied by computer control as a function of accelerator gantry angle. The desired width for each section of the collimator vs gantry angle will be determined by computer optimization, which will examine the influence of variable aperture width vs gantry angle on the chest wall dose distribution and will pick the width for each arc segment which optimizes the dose uniformity across the entire chest wall. The depth of electron penetration will be adjusted through use of multiple electron energies and through individualized bolus thickness in order to minimize the dose to the underlying lung. Electron beam characteristics for the clinically available energies will be tabulated for field widths from 3cm to 7cm. An existing routine which optimizes dose by adjusting electron field weight will be extended to optimize dose by adjusting electron field width. Computer simulations of optimized and unoptimized dose distributions will be performed for a selected group of previously treated electron arc patient contours in which dose inhomogeneity was seen in clinical treatment plans. A prototype variable vane electron collimator will be built and tested in phantom studies. A computer interface will be constructed to vary the individual vane widths as a function of gantry angle, based on the results of the computer optimization. Phantoms representing the extremes of patient anatomy seen clinically will be constructed. Using these specially constructed phantoms, thermoluminescent dosimetry and film densitometry will be used to verify the dose distributions. Review and evaluation of the optimized dose distributions will be accomplished in conjunction with a radiation oncologist experienced in photon and electron beam techniques for treatment of the post mastectomy chest wall. The assessment will quantitate the differences seen and evaluate their potential clinical significance. In a second phase (beyond this request for support), the optimized system will be tested clinically utilizing the patient base established over the past few years during our preliminary electron arc studies.

摘要：这项工作的目的是调查 电子电弧疗法中的动态治疗技术。 几个 电子电弧疗法的一年经验 乳腺癌乳腺癌切除术后的妇女导致了一系列 该技术中的技术和操作修改。 这 超过50位患者的经验证明了可取性 为了进一步优化胸部的剂量分布 墙，除了我们能够使用固定的 塑造电子准直仪。 我们建议这样做 通过动态运动的动态运动 电子电弧期间的叶片电子准直仪。 光圈宽度 多频道准直仪的每个部分都会有所不同 计算机控制是加速器龙门角的函数。 这 准直仪与龙门角的每个部分所需的宽度 将通过计算机优化确定，该优化将检查 可变孔径宽度与龙门角的影响在 胸壁剂量分布，并将为每个弧选择宽度 优化整个剂量均匀性的细分市场 胸壁。 电子渗透深度将被调整 通过使用多个电子能量并通过 个性化的推注厚度，以最大程度地减少对 肺的基础。 临床上的电子束特性 可用的能量将用于从3厘米到现场宽度的表格 7厘米。 现有的例程，通过调整来优化剂量 电子场重量将扩大以优化剂量 调整电子场宽度。 计算机模拟 将执行优化和不优化的剂量分布 对于选定的一组先前处理的电子弧患者 在临床上看到剂量不均匀性的轮廓 治疗计划。 原型变量叶片电子准直仪 将在幻影研究中构建和测试。 计算机接口 将构建以改变单个叶片宽度为 根据计算机的结果，龙门角的功能 优化。 代表患者极端的幻影 将在临床上构建解剖结构。 特别使用这些 构造的幻影，热发光剂量法和膜 光密度测定法将用于验证剂量分布。 审查 对优化剂量分布的评估将是 与辐射肿瘤学家一起完成 经验丰富的光子和电子束技术 治疗乳房切除术后胸壁。 评估 将量化所看到的差异并评估其潜力 临床意义。 在第二阶段（超出此要求 支持），优化系统将在临床上进行测试 在我们的过去几年中，患者基础建立了 初步电子弧研究。