EXTENSION OF THE NET FRACTIONAL DEPTH DOSE FOR INHOMOGENEITY CORRECTION

对身体组织中不均匀性影响的校正是 在治疗优化中相当重要，特别是， 胸部区域的病变，如乳腺肿瘤， 食道或者肺 CT的出现使这一点变得有意义。 的 最近描述的NFD已经通过并入 场尺寸以及深度参数中的密度缩放概念， 在分析的形式主义，从而包括纠正 不均匀性 该方法现在包括对以下影响的校正： 二次电子传输的一组重要的条件。 进一步 需要做的工作是将电子输运校正纳入近 光束边缘和较大场中的小不均匀性。 述的方法 似乎是准确的，通用的，易于实施。

The correction for the effect of inhomogeneity in body tissue is of considerable importance in the treatment optimization especially, of lesions in the thoracal region, such as the tumors of the breast, the esophagus, or the lung. The advent of CT has made this meaningful. The recently described NFD has been extended by the incorporation of the density scaling concept in the field size as well as the depth parameter, in the analytical formalism, thus including correction for inhomogeneities. This method now includes correction for the effect of secondary electron transport for a significant set of conditions. Further work needs to be done to incorporate the electron transport correction near the beam edges and for small inhomogeneities in larger fields. The method appears to be accurate, versatile and easy to implement.