ORNL is developing electronic chips and other high-tech diagnostic tools for quicker, more accurate assessments of hospitalized civilians and injured soldiers.
Hi-Tech for Health
On Christmas Eve in 1994, Tom Ferrell’s 18-month-old son, Brian, was hospitalized with pneumonia. He was on a respirator in intensive care for two weeks. “I was dismayed to see all the wires connected to my son,” says Ferrell, a researcher in ORNL’s Life Sciences Division (LSD). “My wife and I couldn’t pick him up and hug him easily. I wanted to find a way to develop a wireless sensor that monitors vital signs—body temperature, pulse rate, blood pressure, and blood oxygen—and alerts medical personnel to a sudden health problem.”
A young patient who suffers from grand mal seizures is tethered by wires and cords to a medical monitoring machine. A telesensor chip could detect temperature spikes and relay timely information on the need for treatment to prevent this boy from having a seizure.
Fortunately, Ferrell found out that the U.S. Defense Advanced Research Projects Agency (DARPA) was supporting development of a “personal status monitor” for soldiers. So he wrote a proposal, and by early 1996, the funds started rolling in. A year later a team from ORNL, the University of Tennessee at Knoxville (UTK), and the University of Virginia had developed a temperature-measuring telesensor chip.
The chip, which is about one-eighth the size of a postage stamp, uses bipolar transistors whose electronic properties are sensitive to temperature. It can be attached to a finger or placed in an ear. There it can measure body temperature and transmit a reading when queried by a receiver in a remote intelligence monitor.
Although developed for military uses, the temperature chip could be useful at home or in the hospital. For example, a chip could warn of a spike in body temperature that might lead to a seizure in a child or brain damage in a cancer patient undergoing chemotherapy. By heeding the instant information and making the appropriate response, such as taking a pill, patients can avert a health crisis.
Wireless monitors could vastly improve decision making by medics in the military. On the battlefield, some soldiers are mortally wounded, some are badly injured but conscious, and others are hurt yet are able (usually with treatment) to resume fighting. While under fire, medics must decide quickly which wounded soldiers must be treated first to get them back on their feet and ready to fight. Medics also must determine which wounded soldiers can be saved from death by rapid treatment and transport to a hospital.
“These choices are difficult to make in the heat of battle without instant information,” says Ferrell. “Our proposed technology would improve the speed and quality of the information flow.”
ORNL researchers are also developing wireless chips for soldiers that can measure pulse rate (to help a medic determine whether a soldier is still alive) and blood pressure (which drops dramatically if a wounded soldier is bleeding). The idea is that each soldier would wear several wireless microchips embedded in clothing, a finger ring, a boot, or even an earring. Each chip would send measurements by radio signals to units on the soldier’s belt and helmet. The units would then analyze the physiological data to determine if the soldier is injured or ill. If either is the case, radio signals would be sent to the helmet of a medic to alert him that this soldier, among the ten soldiers in his care, needs his immediate attention.
“The wireless, digital chip has several advantages over conventional equipment,” Ferrell says. “Wearing a tiny chip is much more comfortable than being attached by wires to a machine. The chip allows automated monitoring. It enables medical personnel to diagnose a condition remotely. It is low in cost. Because the chip system is so portable, it is easier to transport a patient whose vital signs must be constantly monitored.”
What are the ultimate goals of researchers working with Ferrell in LSD and at UTK, in collaboration with Stephen Smith, Alan Wintenberg, Nance Ericson, and others in ORNL’s Instrumentation and Controls (I&C) Division? “One aim,” says Ferrell, “is to develop an array of chips to monitor a person’s body functions all at once. Another goal is to give each chip a radio signal with a unique identifier pattern so that alerted medical staff will know who needs to be cared for immediately.”
Shedding Light on Cancer
Tuan Vo-Dinh of ORNL (left) and Bergein Overholt and Masoud Panjehpour, both of Thompson Cancer Survival Center of Knoxville, developed a new laser technique for nonsurgically diagnosing cancerous tumors in the esophagus. The technique is now being tested in clinical trials.
A woman woke up feeling chest pain and intense nausea. She rushed to the bathroom and vomited blood. She called her doctor, described her symptoms, and told him that she had suffered severe indigestion for years. He suspected cancer of the esophagus, the muscular tube through which food passes from the pharynx to the stomach. He sent her to the nearby Thompson Cancer Survival Center (TCSC) in Knoxville, Tennessee.
Cancer of the esophagus is one of the most fatal types of cancer in the world. That’s the bad news. The good news is that it can be controlled if diagnosed and treated early.
In the past, the only way to find out accurately whether a patient had the early stages of esophageal cancer was to surgically remove tumor cells from the esophagus. These cells were then sent to a special laboratory and studied under a microscope to determine if the tumor was cancerous or benign. A technology partly developed at ORNL will eventually allow some patients to avoid surgery if their esophageal cells prove to be noncancerous.
The woman described above had to have a surgical biopsy, but she was glad to participate in a test of the optical biopsy sensor developed by Tuan Vo-Dinh of ORNL’s LSD and Bergein Overholt and Masoud Panjehpour, medical researchers at TCSC. She learned that preliminary research studies of optical biopsy at TCSC have a high accuracy rate.
“If results of future tests are successful, use of the optical biopsy sensor may eliminate the need for surgical biopsy in many future patients being tested for cancer,” Vo-Dinh says. “It will also provide a much faster diagnosis than surgical biopsy. As a result, earlier treatment can be administered and patients without cancer won’t have to worry so long about the possibility of having it.”
For the optical biopsy test, while the patient is sedated, the doctor inserts an endoscope—an instrument that allows visual examination of the interior of an organ such as the stomach—through her mouth and into her esophagus. Traveling through the optical fiber in the endoscope, blue light from a pulsed nitrogen dye laser illuminates tissue in the patient’s esophagus. An optical fiber cable is inserted in another channel of the endoscope to collect and transmit light produced by her esophageal tissue after it is excited by laser light. Upon absorbing the light, the tissue emits light with a characteristic pattern of wavelengths, called a laser-induced fluorescence spectrum. Normal tissue has a spectral pattern different from that of cancerous tissue.
Vo-Dinh and his colleagues developed an algorithm that enables a computer to compare the measured fluorescence patterns with the known spectral characteristics of light from both cancerous and normal esophageal cells. The light pattern from the woman’s cells matched that of cancerous cells. She also learned from the surgical biopsy that she has a cancerous tumor but, because it’s in an early stage, treatment should make her well.
“Because the results of these tests have been successful for esophageal cancer,” Vo-Dinh says, “we are planning to develop optical biopsy techniques for use in detecting cancer in the colon, cervix, lung, and bladder.” (See the Incredible Shrinking Labs article for information on Vo-Dinh’s development of a multifunctional biochip that may be used to diagnose diseases.)
Non-invasive Diagnoses of Brain InjuryWhen you’re hit over the head, blood from an artery may begin spilling between your skull and brain. You may not have any symptoms of epidural hematoma until pressure in the cranium grows, blocking blood flow through the brain. To keep patients from undergoing this “second injury,” doctors may take CAT scans and monitor the brain using surgically implanted sensors to help determine the appropriate treatment.
A group led by Vo-Dinh is developing a noninvasive, portable, easy-to-use, and relatively inexpensive device for monitoring brain injury patients. It uses a focused beam of ultrasound waves of an appropriate frequency and a special instrument design that provides an efficient signal for detecting a brain injury. If a lesion, blood clot, or tumor is present, the left-right symmetry of ultrasound echo patterns in the brain may be distorted, indicating the presence of a pathological condition or abnormality. The device has been tested on livestock such as pigs. It will be tested on other animals and may be ready for clinical trials later in 1999. It may also be used to monitor spinal cord injuries.
“This technique should be a significant advance in the care of people with head trauma to limit or prevent brain damage,” says Vo-Dinh. Vo-Dinh’s collaborators on the project are Stephen Norton (former ORNL staff member) and two members of Vo-Dinh’s group—Joel Mobley, a postdoctoral research associate, and Paul Kasili, a graduate student. The development of the ultrasound monitor is supported by the U.S. Army Medical Research and Materiel Command. The device will likely be used to save the lives of both soldiers and civilians.
Lung Diagnosis Monitor
In this simulation, Jeff Ball plays the role of an injured soldier who may have a serious chest injury. After placing a thorax monitor on Ball, a medic, played by Bob Vines, checks his wearable computer for breathing “signals” that indicate a particular lung disorder.
A soldier with a chest wound lies bleeding on the battlefield. How critical is the wound? Has the lungs’ ability to function been impaired? Is the victim about to suffer pulmonary distress? If the medic could get an accurate and rapid diagnosis of the problem, the correct therapeutic intervention could be started to save the soldier’s life. Medical personnel could then give the proper care to boost the soldier’s chances of survival.
In response to the need for rapid diagnoses of lung disorders and distress, Glenn Allgood and Dale Treece, both in the I&C Division, and the Walter Reed Army Institute of Research (WRAIR) are developing a high-tech device that monitors and diagnoses the sounds of breathing. This advanced pulmonary monitoring system for identifying lung disorders is designed for both field and clinical use.
“We envision that this diagnostic system may someday provide Army medical personnel with a rapid, accurate diagnostic tool that will help them manage life-threatening respiratory problems,” says Allgood, the principal investigator. “The technology is being developed for use in mobile hospital units, helicopters, and hospital emergency rooms. But one day it may be used at home.
“It could become a diagnostic tool embedded in crib mattresses to monitor babies’ breathing for signs of respiratory failure or distress linked to problems such as sudden infant death syndrome. It could be used to monitor people having asthma and pneumonia or to determine whether a person experiencing breathing problems has a lung disorder or instead is suffering from stress or some other problem accompanied by respiratory changes.”
The lung diagnostic system will combine novel sensors to be placed on the chest or thorax region and an advanced algorithm suite to distinguish between acoustic signatures from normal lungs and those expressing pathological disorders. Fortunately, disorders such as emphysema, pulmonary fibrosis, and pneumonia have their own characteristic acoustic signatures—unique patterns of abnormal sounds superimposed on normal breathing sounds shown as a series of peaks of different heights and distances from one another. So detection of these signatures can help doctors identify lung disorders.
The ORNL-developed algorithm has been tested on a small data set from patients with healthy lungs and known lung diseases to obtain the acoustic signature for each condition. Signatures linked to known disorders are stored in a data base. The ORNL algorithm compares the acoustic signature of a patient with an unknown disease with the signatures in the data base. If a match is detected, the disease can be diagnosed.
Tests show that the algorithm can accurately analyze data obtained from digital stethoscopes and thorax sensors. The data may be displayed on a laptop computer or small computer worn on the body. ORNL is developing another device that may be more useful for the battlefield and better able to obtain data in lower frequency ranges.
Here’s one scenario of how it could work. In the battlefield, as part of his combat equipment, the soldier could either wear the sensor or have designated places on the body where the medic could put one (such as the optical acoustic sensor with a fiber-optic coupler invented by David Gerdt of Empirical Technologies Corporation). The sensor would then be linked, either wirelessly or by a tether, to a wearable computer carried by the medic. Acoustic measurements from the soldier would then be analyzed, providing a qualified measurement of lung function. The medic would then down link the data and administer appropriate care.
This device is being evaluated at ORNL to determine its ability to distinguish among different pathological disorders. Clinical tests of the ORNL algorithm using new sensor configurations will be conducted in 1999 at WRAIR.
New Hope for Burn VictimsWhen Karla was trapped in a house fire, she received third-degree burns over 90% of her body. In the burn therapy unit, doctors surgically scraped and cut out the dead tissue to promote growth of new tissue. They had to quickly extract the tissue to prevent infection. This technique of débridement is very painful but was necessary to save her life.
A group led by Glenn Allgood is developing an alternative method that is expected to ease the pain of burn therapy. It will use a two-laser system to detect and remove the dead tissue almost simultaneously down to the cellular level. The idea is to avoid the needless removal of healthy tissue, a problem with today’s methods.
“We are aware of a prototype laser system that scans a burn area, determines the laser power requirements, and then removes a layer of the dead tissue, repeating the process until the area is clean,” Allgood says. “The problem is that the patient may move between the imaging and the débriding. Our laser system will work almost instantly, so the patient will be in the same position between tissue mapping and removal.”
Laser light is reflected differently from burned tissue than from normal tissue. The reason: Unlike dead tissue, normal tissue contains blood—in particular, hemoglobin, the iron-containing pigment in red blood cells. Laser light of a certain frequency is reflected back from hemoglobin in a characteristic pattern that differs from that of light scattered from dead tissue. Recent ORNL experiments on interlipid fluid (which mimics hemoglobin) suggest that laser radar can determine the extent and depth of burned skin. Funded by the U.S. Army Medical Research and Materiel Command, Allgood, Don Hutchinson, Roger Richards, and Bill Dress, all of the I&C Division, have developed a light detection and ranging (lidar) system that combines a coherent frequency-modulated continuous wave laser with a unique configuration of optical components. They have determined the differences in reflection patterns for simulated dead and healthy skin and recorded them in a data base for the proposed laser treatment system.
They have prepared an algorithm that would compare the real-time laser light reflection patterns gathered by the optical components with the stored data. The instant information will enable a computer to construct a three-dimensional image map that shows where dead tissue meets the healthy blood layer below the burn. Using the lidar map, the computer will precisely guide a pulsed laser in a less traumatic “burning” of the dead tissue, leaving the healthy tissue intact.
“We believe,” says Allgood, “that this technique will hasten the healing of burn patients.”
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