Grosenick Dirk, Wabnitz Heidrun, Moesta K Thomas, Mucke Jörg, Schlag Peter M, Rinneberg Herbert
Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany.
Phys Med Biol. 2005 Jun 7;50(11):2451-68. doi: 10.1088/0031-9155/50/11/002. Epub 2005 May 18.
Within a clinical trial on scanning time-domain optical mammography reported on in a companion publication (part I), craniocaudal and mediolateral projection optical mammograms were recorded from 154 patients, suspected of having breast cancer. Here we report on in vivo optical properties of the subset of 87 histologically validated carcinomas which were visible in optical mammograms recorded at two or three near-infrared wavelengths. Tumour absorption and reduced scattering coefficients were derived from distributions of times of flight of photons recorded at the tumour site employing the model of diffraction of photon density waves by a spherical inhomogeneity, located in an otherwise homogeneous tissue slab. Effective tumour radii, taken from pathology, and tumour location along the compression direction, deduced from off-axis optical scans of the tumour region, were included in the analysis as prior knowledge, if available. On average, tumour absorption coefficients exceeded those of surrounding healthy breast tissue by a factor of about 2.5 (670 nm), whereas tumour reduced scattering coefficients were larger by about 20% (670 nm). From absorption coefficients at 670 nm and 785 nm total haemoglobin concentration and blood oxygen saturation were deduced for tumours and surrounding healthy breast tissue. Apart from a few outliers total haemoglobin concentration was observed to be systematically larger in tumours compared to healthy breast tissue. In contrast, blood oxygen saturation was found to be a poor discriminator for tumours and healthy breast tissue; both median values of blood oxygen saturation are the same within their statistical uncertainties. However, the ratio of total haemoglobin concentration over blood oxygen saturation further improves discrimination between tumours and healthy breast tissue. For 29 tumours detected in optical mammograms recorded at three wavelengths (670 nm, 785 nm, 843 nm or 884 nm), scatter power was derived from transport scattering coefficients. Scatter power of tumours tends to be larger than that of surrounding healthy breast tissue, yet the 95% confidence intervals of both medians overlap.
在一篇配套出版物（第一部分）报道的关于扫描时域光学乳腺造影的临床试验中，对154名疑似患有乳腺癌的患者进行了头尾位和内外侧位投影光学乳腺造影记录。在此，我们报告了87例经组织学验证的癌瘤子集的体内光学特性，这些癌瘤在两个或三个近红外波长记录的光学乳腺造影中可见。肿瘤吸收系数和约化散射系数是根据采用光子密度波在球形不均匀体（位于均匀组织平板中）的衍射模型，在肿瘤部位记录的光子飞行时间分布推导得出的。如果有相关信息，分析中会纳入从病理学获取的有效肿瘤半径以及从肿瘤区域的离轴光学扫描推断出的肿瘤沿压缩方向的位置等先验知识。平均而言，肿瘤吸收系数比周围健康乳腺组织的吸收系数高出约2.5倍（670纳米），而肿瘤约化散射系数则大出约20%（670纳米）。根据670纳米和785纳米处的吸收系数，推导出肿瘤及周围健康乳腺组织的总血红蛋白浓度和血氧饱和度。除了少数异常值外，观察到肿瘤中的总血红蛋白浓度相较于健康乳腺组织系统性地更高。相比之下，血氧饱和度被发现对肿瘤和健康乳腺组织的区分能力较差；两者的血氧饱和度中位数在统计不确定度范围内相同。然而，总血红蛋白浓度与血氧饱和度的比值进一步提高了肿瘤与健康乳腺组织之间的区分度。对于在三个波长（670纳米、785纳米、843纳米或884纳米）记录的光学乳腺造影中检测到的29个肿瘤，散射功率是根据传输散射系数推导得出的。肿瘤的散射功率往往高于周围健康乳腺组织的散射功率，但两者中位数的95%置信区间重叠。
