Acoustical holography "sees" inside the living object Excised uterus from white rat with two-week-old fetuses and same fetuses seen with acoustical holography
HOLOGRAPHY:
Seeing Beneath the Skin An acoustical holography technique that produces live TV images of living animal kidney, stomach, intestine, and vascular system tissues has been developed by scientists at BattelleNorthwest, Richland, Wash. Details of the method and its applications in diagnosing internal disease and fetal abnormalities were revealed by Battefle pathologist Melvin R. Sikov at the American Association of Physicists in Medicine meeting in Chicago. Acoustical holography is a relatively new technique analogous to optical holography. In optical holography an interference pattern formed by combination of light waves from an object and from a reference wave are recorded on photographic film. When the film is developed and illuminated with laser light, the original object is presented to the viewer as a reconstructed image, the hologram. In Battelle's acoustical holography, ultrasonic transducers placed in water emanate ultrasonic energy beams that interfere at a water-air interface. A laser beam is shone on the pattern and the light is diffracted back through a system of optical lenses that terminates in a video camera, producing a television image. Acoustical holography has the advantage that sound can penetrate many objects that light can't. In addition, acoustical holography—being a "real-time" process—shows the internal structure of the object at the exact moment of viewing. The technique gives resolution of soft tissue as well as bone, something that x-rays can't easily do, notes John Deichman, associate manager of applied physics and instrumentation. And when viewed on a TV screen a subject can be moved or rotated to obtain different and selected views within the body. Thus, the method is likely to be used to study muscular structure and action. 16 C&EN DEC. 14, 1970
Limited amounts of the synthetic wood pulp have been made in a small pilot plant at Camas, Wash., says Ernest A. Mitchell, executive vice presir dent, but the process is still in the experimental stage at present. Mr. Mitchell explains that the synthetic fiber, which is fed into a paper machine as is normal wood pulp, produces "excellent printing paper with high brightness and opacity. Because of its inherent brightness, no bleaching of the synthetic fiber is required." The synthetic wood pulp can also be mixed with wood fiber to produce paper grades requiring particular qualities and characteristics, Mr. Mitchell says. "We view synthetic wood pulp primarily as a supplementary fiber source," he asserts. "Its cost is definitely higher than bleached kraft pulp made from wood. However, it becomes competitive as raw material for paper manufacturing in countries which are short on timber resources." Japan, of course, fits Mr. Mitchell's description perfectly. CZ has agreed to negotiate with Mitsui Petrochemical Industries, Ltd., Tokyo, on a possible joint venture to make synthetic wood pulp for the Japanese home market. SPECIALTIES: The current paper market in Japan is Out of the Woodwork about 10 million tons a year and is growing at a yearly rate of 9%. The Several years ago Crown Zellerbach, joint venture, which would use CZ's giant pulp and paper company, was technology, would be limited to pulp fond of promoting its products with production and wouldn't extend to paa catchy advertisement in the Wall Street Journal—"Look what came out permaking. In recent years the Japanese govof our woodwork." Out of CZ's elegantly woodworked corporate offices ernment has been supporting development of synthetic materials which can last week came the fact that the San supplement wood fiber in the paperFrancisco-based company has develmaking process. Crown Zellerbach, oped a process for converting ethylene for example, already has in the market gas into synthetic wood pulp. The test stage in the U.S. a new synthetic pulp can be made into paper on conpaper being developed under a North ventional papermaking equipment, American license from Nippon Kakoh the company claims. CZ isn't disclosSeishi, K.K., a specialty papermaker ing any details of the process for which it has filed patents both here and in Japan. The product is based on polystyrene and complements paper abroad, but the final wood pulp is a grades derived from synthetic woodpolyethylene-type material, according pulp. to a company spokesman. Picture resolution of the object is determined by the frequency of the sound waves used, Mr. Deichman says. The Battelle scientists use frequencies of 3 MHz. for their tissue studies. In this way, they have determined some structural details of a 15-day-old rat embryo less than 0.5 inch long. From a medical standpoint, the method has potential in early sex determination of a fetus and detection of abnormalities during gestation, deterniining the exact location of blood clots for surgical removal, and interior imaging of organs during surgery, Dr. Sikov suggests. Although the Battelle instrumentation and technique aren't yet available commercially for medical purposes, a commercial acoustical imager is available from Holosonics, Inc., a Richland firm formed by three former Battelle scientists. Byron Brenden, who did much of the early pioneering work in acoustical holography while at Battelle, Dr. George Garlick, and Dr. Victor Neeley make and market their imager, primarily for nondestructive testing, for less than $30,000.
