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 超声成像和组织表征算法的应用 癌症检测和诊断。 目前B超检查方法 在3 Mhz下提供典型地约1至3 mm的空间分辨率， 深度为1至10 cm，随深度进一步降低。 表征 通过吸收来自B扫描数据的组织的分辨率由 理论上超过1厘米。 超声波透射断层扫描显示 癌症检测的定量准确性和特异性，但差 空间分辨率约为1 cm。 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。 特别是我们 合成聚焦算法提供接近1/2的空间分辨率， 1/4 mm，（即，二分之一波长），具有半定量精度。 频率外推和有限差分算法提供了高 分辨率和定量精度或透射成像数据， 良好的信噪比。 算法上的又一突破 实现现在允许逆散射的快速计算 精确（非线性）Helmholtz波动方程的解 具有不均匀密度p的组织的粘弹性流体模型， 声音C和吸收A特性。 该解决方案，如计算，使用 具有sinc基函数的矩量法是鲁棒的（噪声容限 稳定），具有极高的空间分辨率， 上述定义的组织参数P，C， a. 一个类似的，但也许更快，收敛的解决方案，黎卡提波 方程也已制定。 由于迄今为止的结果非常好， 传感器阵列扫描仪将被建造，以更快地获得更准确的数据 并帮助评估全尺寸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.