Department of Physics, Royal Institute of Technology (KTH), Stockholm, Sweden. Philips Mammography Solutions, Kista, Sweden.
Phys Med Biol. 2018 Oct 30;63(21):215023. doi: 10.1088/1361-6560/aae78c.
X-ray characteristics of body tissues are of crucial importance for developing and optimizing x-ray imaging techniques, in particular for dosimetry and spectral imaging applications. For breast imaging, the most important tissues are fibro-glandular, adipose and skin tissue. Some work has and is being done to better characterize these tissue types, in particular fibro-glandular and adipose tissue. In the case of breast skin, several recent studies have been published on the average skin thickness, but with regards to x-ray attenuation, the only published data, to the knowledge of the authors, is the elemental composition analysis of Hammerstein et al (1979 Radiology 130 485-91). This work presents an overview of breast skin thickness studies and a measurement of the effective atomic number ([Formula: see text]) of breast skin using spectral mammography. [Formula: see text], which together with the density forms the attenuation, is used to validate the work by Hammerstein et al, and the dependence of clinical parameters on [Formula: see text] is explored. Measurements were conducted on the skin edge of spectral mammograms using clinical data from a screening population (n = 709). The weighted average of breast skin thickness reported in studies between 1997 and 2013 was found to be [Formula: see text] mm. Mean [Formula: see text] was found to be 7.365 (95% CI: 7.364,7.366) for normal breast skin and 7.441 (95% CI: 7.440,7.442) for the nipple and areola. [Formula: see text] of normal breast skin is in agreement with Hammerstein et al, despite the different methods and larger sample size used. A small but significant increase in [Formula: see text] was found with age, but the increase is too small to be relevant for most applications. We conclude that normal breast skin is well described by a 1.56 mm skin layer and the elemental composition presented by Hammerstein et al (1979 Radiology 130 485-91) and recommend using these characteristics when modelling breast skin.
人体组织的 X 射线特征对于开发和优化 X 射线成像技术至关重要，特别是对于剂量学和光谱成像应用。对于乳房成像，最重要的组织是纤维-腺体、脂肪和皮肤组织。已经有一些工作，并且正在进行更好地描述这些组织类型，特别是纤维-腺体和脂肪组织。在乳房皮肤的情况下，最近已经有几项研究发表了平均皮肤厚度，但就 X 射线衰减而言，据作者所知，唯一发表的数据是 Hammerstein 等人的元素组成分析（1979 年 Radiology 130 485-91）。这项工作概述了乳房皮肤厚度研究，并使用光谱乳房摄影术测量了乳房皮肤的有效原子数([Formula: see text])。[Formula: see text]，与密度一起形成衰减，用于验证 Hammerstein 等人的工作，并探索了临床参数对[Formula: see text]的依赖性。使用来自筛查人群（n = 709）的临床数据在光谱乳房照片的皮肤边缘进行了测量。发现 1997 年至 2013 年期间研究报告的乳房皮肤平均厚度为[Formula: see text]mm。发现正常乳房皮肤的平均[Formula: see text]为 7.365（95%CI：7.364，7.366），乳头和乳晕为 7.441（95%CI：7.440，7.442）。正常乳房皮肤的[Formula: see text]与 Hammerstein 等人一致，尽管使用了不同的方法和更大的样本量。随着年龄的增长，[Formula: see text]略有但显著增加，但增加幅度太小，对大多数应用都没有意义。我们得出结论，正常乳房皮肤可以很好地用 1.56mm 的皮肤层和 Hammerstein 等人（1979 年 Radiology 130 485-91）提出的元素组成来描述，并建议在建模乳房皮肤时使用这些特性。
