BREAST IMAGING USING PICOSECOND PULSES OF LIGHT

美国癌症协会声称， 在美国，每11名女性中就有一名患乳腺癌。 一 通过定期筛查， 所有无症状的妇女，特别是那些风险最大的妇女。 长期 本研究的目的是开发一种能够 使用无害剂量的可见光， 或近红外辐射。 因为小的，但有限的危险 与暴露于X射线有关，这是一种乳腺癌筛查方法， 使用非电离辐射将具有相当大的临床益处， 特别是如果它表现出诊断性能相当于或 比X光乳房X光检查更好 由于光通过软组织的压倒性散射， 现有乳腺透照检查方法空间分辨率性能 非常贫穷。 没有光线可以穿透人类的乳房， 相当分散。 但拟对是非曲直进行调查 以及用于产生高分辨率图像的各种方案的局限性 利用少量的透射辐射， 乳房沿着一条接近放射线之间的直线的路径 源和检测器。 成像方法包括记录和 在所有透射光子的飞行时间之间进行区分，以及 用一小部分传播时间最短的光 通过乳房的图像。 成像系统的两个主要组成部分 是皮秒脉冲激光器和扫描相机 A中的光子 入射到乳房表面上的单个激光脉冲将被散射 在整个组织中，并且条纹相机测量 作为时间的函数的透射光。 首先检测到的光子将 偏离光轴最小。 测量的强度 在光子第一次从光子中出现之后的一段很短的时间内， 将取决于组织的吸收特性 包含在围绕光轴的某个窄体积元件内。 然后，可以通过平移投影图像来构建单个投影图像。 在乳房表面上的二维光轴。 初步 实验已经戏剧性地说明了飞行时间的潜力 显像 主要目标是开发和测试一些拟议的成像 方案，并产生一个原型装置能够实现单一的 投影透射图像的空间分辨率为几 毫米或更好。 此外，同样的实验安排将 用于探索通过乳房获得切片图像的方法， 计算机断层扫描。

The American Cancer Society claims that there is a lifetime incidence of breast cancer in the United States of about one woman in eleven. A significant reduction in mortality would be gained by regular screening for all asymptomatic women, particularly for those most at risk. The long term objective of this research is the development of a device which is able to detect minimal cancers in the human breast using harmless doses of visible or near-infrared radiation. Because of small, but finite hazards associated with exposure to x-rays, a breast cancer screening method that uses non-ionizing radiation would be of considerable clinical benefit, particularly if it demonstrated a diagnostic performance equivalent to or better than x-ray mammography. Because of the overwhelming scatter of light through soft tissue, the spatial resolution performance of current breast transillumination methods is extremely poor. No light can penetrate a human breast without considerable scatter. However, it is proposed to investigate the merits and limitations of various schemes for producing high-resolution images using the small amount of transmitted radiation that is scattered through the breast along a path close to the straight line between the radiation source and the detector. The imaging method involves recording and discriminating between the times-of-flight of all transmitted photons, and using a fraction of the light with the shortest travel times to construct an image through the breast. The two major components of an imaging system are a picosecond pulse laser, and a streak camera. The photons within a single laser pulse incident upon the surface of a breast will be scattered throughout the tissue, and the streak camera measures the intensity of the transmitted light as a function of time. The photons detected first will have been deviated least from the optical axis. The intensity measured over some very small period of time after the photons first emerge from the tissue will be dependent upon the absorption properties of the tissue contained within some narrow volume element surrounding the optical axis. A single projection image may then be constructed by translating the optical axis in two dimensions over the surface of the breast. Preliminary experiments have dramatically illustrated the potential of time-of-flight imaging. The primary objectives are to develop and test a number of proposed imaging schemes, and to produce a prototype device capable of achieving single projection transmission images with a spatial resolution of a few millimeters or better. In addition, the same experimental arrangement will be used to explore methods of obtaining slice images through a breast using computed tomography.