CANCER DETECTION BY ULTRASOUND INVERSE SCATTERING

我们建议进一步开发和评估几个新的和令人兴奋的 超声成像和组织定征算法的应用 癌症检测和诊断。目前的B超检查方法 在3兆赫时提供通常约1至3毫米的空间分辨率 深度1到10厘米，随着深度的增加会进一步退化。表征 通过从B超数据吸收的组织的分辨率由 1厘米以上的理论。超声透射层析显示良好 癌症检测的定量准确性和特异性，但很差 空间分辨率约为1厘米。 我们的新成像算法克服了上述方法的局限性。 并提供理论极限或接近理论极限的性能。尤其是，我们的 合成聚焦算法提供接近1/2的空间分辨率 1/4 mm(即半个波长)，具有半定量精度。 频率外推和有限差分算法提供了高 数据的分辨率和定量准确性或传输成像 良好的信噪比。算法方面的又一突破 实现方式现在允许快速计算逆散射 方程的精确解(未线性化) 非均匀密度p、速度p的组织粘弹性流体模型 声音c和吸收a的特性。根据计算，此解决方案使用 具有正弦基函数的矩量法是健壮的(容忍噪声 和稳定)，具有极高的空间分辨率，并提供高度 上述定义的组织参数p，c， A.里卡提波的类似但可能更快的会聚解 并建立了相应的方程。 由于到目前为止结果很好，一种电子寻址的原型 将建造换能器阵列扫描仪，以更快地获得更准确的数据 并帮助评估全面临床乳房和腹部的设计 扫描仪。

We propose to further develop and evaluate several new and exciting ultrasound imaging and tissue characterization algorithms for application to cancer detection and diagnosis. Present B-scan ultrasound methods provide a spatial resolution typically of about 1 to 3 mm at 3 Mhz for depths of 1 to 10 cm, which degrades further with depth. Characterization of tissue by absorption from B-scan data has a resolution dictated by theory of more than 1 cm. Ultrasound transmission tomography shows good quantitative accuracy and specificity for cancer detection, but poor spatial resolution of about 1 cm. Our new imaging algorithms overcome the limitations of the above methods and provide performance at or near theoretical limits. In particular, our synthetic focus algorithms provide spatial resolution approaching 1/2 to 1/4 mm, (i.e., one-half wavelength) with semiquantitative accuracy. Frequency extrapolation and finite difference algorithms provide high resolution and quantitative accuracy or transmission imaging for data with good signal-to-noise ratios. An additional breakthrough in algorithm implementation now permits fast computation of the inverse scattering solution of the exact (not linearized) Helmholtz wave equation for a visco-elastic fluid model of tissue with inhomogeneous density p, speed of sound c, and absorption a, properties. This solution, as computed, using the method of moments with sinc basis functions, is robust (noise tolerant and stable), has extremely high-spatial resolution and provides highly accurate quantitative images of the above defined tissue parameters p, c, a. A similar, but perhaps faster, converging solution to the Riccati wave equation has also been formulated. Since results to date are excellent, a prototype electronically addressed transducer array scanner will be built to obtain more accurate data faster and to help evaluate a designs for full-scale clinical breast and abdominal scanners.