Modulated electron beams using multi-segmented multileaf collimation
Modulated electron beams using multi-segmented multileaf collimation
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DOI：
10.1016/s0167-8140(98)00050-4
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发表时间：
1998-09-01
影响因子：
5.7
通讯作者：
Klein, EE
中科院分区：
文献类型：
--
作者：
Klein, EE
背景和目的：通过调制光子和电子束的适形放射治疗已经描述了许多技术。本文报道了用团注或改变扫描束调制电子束的方法。我们的机构以前调查了使用MLC的固定静态电子场。结果是令人沮丧的，由于广泛的半影与多叶准直电子散射箔。本研究的目的是破译是否使用MLC的多段电子束将提供一个有用的和实用的调制束laking匹配的扩散beam edges.Materials和方法的优势：我们开始通过规划简单的目标形状，如楔形和抛物线形状。我们优化了片段宽度、权重、片段之间的间隙和能量。然后，我们用胶片照射幻影，以证实计算结果。该研究仅限于单平面照射。我们还计划和测量等剂量腮腺靶体积，具有不同的深度从表面到medial aspects.Results：我们发现，我们可以优化分布，通过使用治疗深度和拐点，以获得最佳的部分。使用简单的CET（等效厚度系数）算法的计划治疗得到了合理的成功证实。一个24厘米宽的目标是在5分钟内治疗9个部分，而大多数情况下，包括腮腺体积，在3分钟内治疗。结论：我们已经开发出一种技术，以补充光子调制程序治疗病变接近表面。关于这种技术是否是最佳的，是否比推注技术更有效的争论仍在继续。我们目前正在设计用于优化多个平面中的调制电子MLC束的方法。(C)1998爱思唯尔科学爱尔兰有限公司保留所有权利。
Background and purpose: Conformal radiation therapy by modulation of photon and electron beams has been described for many techniques. Modulation of electron beams with the use of either bolus or altered scanned beams is reported. Our institution previously investigated the use of MLC for fixed static electron fields. The results were dismal due to the wide penumbra associated with multileaf collimated electrons scattered from foils. The purpose of this study was to decipher whether multi-segmented electron beams using MLC would provide a useful and practical modulated beam by laking advantage of matching the diffuse beam edges.Materials and methods: We started by planning simple target shapes, such as wedged and parabolic shapes. We optimized the segment widths, weights, gaps between segments and energies. We then irradiated phantoms using film to confirm the calculations. The study was limited to single-plane irradiation. We also planned and measured isodoses for a parotid target volume that possessed varying depths from surface to medial aspect.Results: We found that we could optimize distributions by using the treatment depth and points of inflection to derive optimal segments. The planned treatments using a simple CET (coefficient of equivalent thickness) algorithm were confirmed with reasonable success. A 24 cm wide target was treated with nine segments in under 5 min, while most cases, including the parotid volume, were treated in under 3 min.Conclusions: We have developed a technique to complement a photon modulation program by treating lesions close to the surface. The debate as to whether this technique is optimal and more efficient than a bolus technique continues. We are currently devising methods for optimizing modulated electron MLC beams in multiple planes. (C) 1998 Elsevier Science ireland Ltd. All rights reserved.