University of Connecticut, Electrical and Computer Engineering Department, Storrs, Connecticut 06269, USA.
J Biomed Opt. 2013 Jan;18(1):16006. doi: 10.1117/1.JBO.18.1.016006.
Ultrasound-guided diffuse optical tomography (DOT) is a promising method for characterizing malignant and benign lesions in the female breast. We introduce a new two-step algorithm for DOT inversion in which the optical parameters are estimated with the global optimization method, genetic algorithm. The estimation result is applied as an initial guess to the conjugate gradient (CG) optimization method to obtain the absorption and scattering distributions simultaneously. Simulations and phantom experiments have shown that the maximum absorption and reduced scattering coefficients are reconstructed with less than 10% and 25% errors, respectively. This is in contrast with the CG method alone, which generates about 20% error for the absorption coefficient and does not accurately recover the scattering distribution. A new measure of scattering contrast has been introduced to characterize benign and malignant breast lesions. The results of 16 clinical cases reconstructed with the two-step method demonstrates that, on average, the absorption coefficient and scattering contrast of malignant lesions are about 1.8 and 3.32 times higher than the benign cases, respectively.
超声引导漫射光学层析成像（DOT）是一种很有前途的方法，可用于对女性乳房中的良恶性病变进行特征描述。我们提出了一种新的两步 DOT 反演算法，其中采用遗传算法的全局优化方法来估计光学参数。将估计结果作为初始猜测应用于共轭梯度（CG）优化方法，从而同时获得吸收和散射分布。模拟和体模实验表明，最大吸收和降低的散射系数的重建误差分别小于 10%和 25%。这与单独使用 CG 方法形成对比，因为 CG 方法会使吸收系数产生约 20%的误差，并且无法准确恢复散射分布。引入了一种新的散射对比度度量方法来对良恶性乳房病变进行特征描述。使用两步法重建的 16 个临床病例的结果表明，恶性病变的平均吸收系数和散射对比度分别比良性病变高约 1.8 倍和 3.32 倍。
