Technology Transfer

Remote Sensing Down to Earth

MEDICINE TODAY HAS A MUCH MORE BROAD range of body-scanning equipment and techniques available to create images of human interiors to aid physicians in diagnosis, treatment and surgery. Much of this technology has stemmed from the space technique known as digital image processing, developed as a means of assembling a picture of a planet or a moon from bits of sensor data sent to Earth in digital form by a distant spacecraft. Image processing technology has been more importantly or more effectively employed beyond the x-ray that shows only a bone's structure—in computer-aided tomography (CAT) scanning, diagnostic radiography, brain and cardiac angiography, sonar body scanning and monitoring surgery.

Space Telescope Looks for Cancer

With the help of Hubble Space Telescope technology, breast biopsies to detect breast cancer can now be performed pain- and scar-free with a needle instead of a scalpel. Breast tissue is imaged more clearly than conventional x-rays, and the patient can walk out of the office and resume normal activities.

The CCD on the left is an advanced, extrasensitive device developed for NASA's Hubble Space Telescope. The virtually identical CCD on the right is a commercial derivative of the Hubble device that has contributed importantly to a new, nonsurgical and much less traumatic breast biopsy technique.

Charged coupled devices (CCDs) are high- technology silicon chips that convert light directly into electronic or digital images. Goddard Space Flight Center headed the development of the advanced, supersensitive CCD installed in the Hubble Space Telescope in 1997. The LORAD Corporation of Danbury, Connecticut, adopted the new CCD for its breast biopsy system. Through this system, the patient lies face down with one breast protruding through an opening to pinpoint the area in question. The doctor then uses the specially designed needle to extract a tiny sample.

The procedure costs about four times less than traditional biopsy surgery. The new procedure also saves the patient time and pain, and it leaves only a small needle mark rather than a large scar.

Body Imaging: MRIs and CAT Scans

In the mid-1960s, as NASA prepared for its Apollo lunar landing program, the Jet Propulsion Laboratory (JPL) developed the technology known as digital image processing to allow for the computer enhancement of Moon photographs. This technology later became the basis for the NASA Landsat satellites.

Physicians and hospitals now use digital image processing to record images of organs in the human body. Two of the most widely used body-imaging techniques are CAT scanning and magnetic resonance imaging (MRI). CAT scan image data are collected by aiming a fan-shaped x-ray beam from a number of different directions around the body. A computer then reconstructs a tomographic (slice-like) image from these multiple views. MRI uses a magnetic field and radio waves to create images, rather than x-rays.

In most cases, a CAT scan is used for bone, while MRI is used for soft tissue (such as the liver). Both methods are often used to obtain a complete diagnosis for a patient. Doctors and engineers are working to combine the best features of MRI and CAT scanning. One of their research tools is a computer program originally developed by NASA to distinguish among Earth surface features in Landsat image processing.

Infrared Thermometer: Temperature in Seconds

A physician studies images acquired on the breast biopsy system.

Here is an amazing statistic: in the United States alone, someone takes someone else's temperature about 2 billion times a year. And that is just in hospitals and doctor's offices! The 2 billion figure does not include all those anxious mothers and fathers checking on their children's fevers.

The latest in thermometer technology was made possible by NASA's ability to measure the temperatures of stars and planets—without ever leaving the ground! Taking the temperature of distant bodies is made possible through the sensing of infrared radiation given off by the star or planet.

Diatek Corporation of San Diego, California, asked NASA to help develop the sensor technology for a handheld thermometer that takes a person's temperature in less than two seconds. The thermometer has a probe that is inserted a little way into the ear. (The patient does not even have to be awake.) The probe is thrown away after use and replaced by a new one, to guard against cross-infection.

Miniaturized Transmitter

In 1999, the NASA-developed "pill transmitter" was expected to monitor mothers and their babies following corrective fetal surgery. The "pill," developed at Ames Research Center, is about one-third of an inch across and one and one-third inches long. An even smaller pill to be developed will be swallowed by astronauts so that NASA can track their vital signs during space travel.

"Nearly every time doctors operate on a fetus, the mother will later undergo pre-term labor that must be monitored," said Carsten Mundt, an electrical engineer on the Sensors 2000! team at Ames. "Pre-term labor is a serious problem that is difficult to predict and monitor with conventional equipment, and often leads to the death of the baby. But if you implant our pill, you can measure pressure changes in the uterus that result from contra ctions. When doctors are able to monitor the magnitude and frequency of contractions, the physicians can identify the onset of pre-term labor early enough to prevent it from becoming life threatening to the fetus."

Earlier, pediatric surgeons at the Fetal Treatment Center pioneered a cesarean surgical approach to treat fetuses suffering from various birth defects, including congenital diaphragmatic hernia. In this condition, a hole in the baby's diaphragm lets internal organs shift from inside the abdomen into the chest cavity, leaving insufficient room for lung development. Sixty to 75 percent of babies born with this condition die. During some of these earlier surgeries, physicians implanted larger sensor-transmitters to monitor mothers and their fetuses.

Recently, Fetal Treatment Center surgeons changed their technique from cesarean to a less intrusive endoscopic method, during which they make small incisions and insert tube-like devices through the mother's abdominal wall. Normally, an endoscope is used to see into the interior of a body or hollow organ. Endoscopic instruments are now also used more frequently in surgeries requiring smaller incisions.

"This minimally invasive method represents the future of fetal surgery," said Michael Harrison, M.D., founding director of the Fetal Treatment Center, who in 1981 performed the world's first corrective surgery on a fetus before birth. "Because there are no commercially available sensor-transmitters small enough to fit through the tubes used in the new endoscopic surgery technique, scientists and engineers on our team developed the pill-shaped device so that it can pass through the tubes," said Ames team member Mike Skidmore. "Our first pill-shaped device can transmit temperatures as well as the pressure of uterine contractions."

Scientists at Ames are testing a prototype version of another pill that can measure and transmit pH, or acidity, in the fetus, according to Chris Somps, a scientist on the Sensors 2000! team. Somps explained that plans also call for even smaller pills that will measure the electrical activity of the fetal heart. These pills will transmit fetal heart data, as well as measurements of the baby's body chemicals, including ionic calcium, carbon dioxide and glucose.

"We would also like to use this technology to study what happens to astronauts during space travel," said Skidmore. "Not only could they swallow the smaller pill transmitters we plan to develop, but we have a conceptual design of small, flat transmitters that can be taped to the body like plastic bandages."

According to Mundt, there are many possible medical uses for this technology. Pills could monitor intestinal pressure changes or stomach acidity in ulcer patients. The acid-base balance in the body is a basic measure of health.

For more information on remote sensing, contact the Technology Commercialization Office at the Jet Propulsion Laboratory. Call: 818/354-2577. Or contact the Technology Commercialization Office at Stennis Space Center. Call: 228/688-1914. For more information on the pill transmitter technology, contact the Technology Commercialization Office at Ames Research Center. Call: 415/604-0893. Please mention you read about it in Innovation.