RADIATION FIELD MODELING

这从根本上说是正在进行的研究和开发。有能力 计算光子束产生的吸收剂量分布和 最一般特性的电子束是至关重要的 在放射治疗中。从概念上讲，这个辐射场模型是以 沿三个相互垂直的参照系的经验分布 行，在“主字段”和数学表达式中描述 视场大小、深度和焦距变化的影响。这一概念 也适用于波束修正装置。方法是 从理论和实践的角度来看，都很有吸引力。这个 目前的调查包括泛化的治疗 不均匀性的影响。描述中的新概念 光束的沿射线分布及其与场大小的关系 已经制定并正在实施个人资料。一种全新的 对电磁场建模的方法正在进行中，并且非常 很有希望。特别令人感兴趣的是大量的 电子能量和灵活应用的需要不同 能量和场形状与光子场相结合。这张网 分数剂量概念(NFD)已被扩展(ENFD)。Enfd 形式主义包括对非均质性的影响的描述，如 作为肺组织。它包括对二次电子传输的修正。

This is fundamentally ongoing research and development. The capability to calculate the distribution of absorbed dose produced by photon beams and electron beams of the most general characteristics is of vital importance in radiotherapy. Conceptually, this radiation field model takes as a basis the empirical distributions along three mutually perpendicular reference lines, in a "master field" and mathematical expressions to describe the effect of variations of field size, depth and focal distance. This concept is applied to the beam-modifying devices as well. The approach is attractive form a theoretical as well as a practical point of view. The present investigations include the generalization of the treatment of the influence of inhomogeneities. New concepts in the description of the along-the-ray distribution as well as the field size dependence of the beam profile have been developed and are being implemented. A completely new approach to electron field modeling is well underway and extremely promising. Of special interest are the implications of the large number of electron energies and the need for flexible application of different energies and field shapes in combination with photon fields. The Net Fractional Dose Concept (NFD) has been extended (ENFD). The ENFD formalism includes the description of the influence of inhomogeneites, such as lung tissues. It includes correction for secondary electron transport.