科学家正在研制新型超声振动显像技术

科学家最近发现一种利用超声振动来捕获肿瘤影像地方法。这种技术涉及对胶质对象使用超声振动来成像，这种胶质对象通常是圆形的，比如血细胞和悬浮在液体中的颗粒。

美国布朗大学的研究人员正在进行一项研究，他们将一束超声波射入身体某个区域来产生射频信号，然后经过处理反应出胶质对象的空间特征。这项技术在组织与血液之间产生500倍对比，使得该技术有助于肿瘤成像，因为根据科学家的说法，肿瘤组织比正常组织具有更多的血管。

直接包绕在颗粒周围体液的电荷与颗粒表面电荷相反。这使得颗粒聚集在一起。当声波撞击胶质状物体的时候，导致环绕颗粒周围的体液产生振动。振动电荷产生交互电流，从而产生射频波谱。

与此相反的是，传统超声成像利用不同密度物质导致声波速度的变化来显示不同组织的影像。根据科学家的说法，这种新技术在2～5年之后即可用于临床乳腺影像检查。这项研究成果发表在2004年11月20日的《应用物理通信》上。

Ultrasonic Vibrations Capture Tumor Images
 
Scientists have discovered a way to utilize ultrasonic vibrations to capture images of tumors. The technique involves using ultrasonic vibrations to image colloidal objects, which are spherical in shape, such as blood cells and particles that are suspended in fluid.

The investigators, from Brown University (Providence, RI, USA), are performing a study in which they shoot a beam of ultrasound through an area of the body to generate a radiofrequency signal, which they then process to produce a spatial representation of colloidal objects. The technique produces a 500-fold contrast between tissue and blood, which makes it potentially useful for imaging tumors because tumors have more blood vessels than normal tissue, according to the scientists.

The fluid directly surrounding a particle carries an electric charge opposite the charge on the surface of the particle. This keeps particles from bunching together. When sound waves hit colloidal objects, they cause the fluid around the particles to oscillate. The oscillating charge produces an alternating current, which products radiofrequency waves.

In contrast, conventional ultrasonic imaging utilizes alterations in speed of the sound waves caused by substances with different densities to image different kinds of tissue. This new technique could be ready for clinical use in mammogram technology in two to five years, according to the scientists. Their study was published in the November 29, 2004, issue of the journal Applied Physics Letter.