Medical miracles.

Despite the slow going against AIDS, Alzheimer's, and some forms of cancer, there's much in modern medicine to be thankful for.

Can you imagine how many of us would have lost a loved one prematurely if pacemakers didn't exist?

Or how many victims of accidents or arthritis might be severely crippled for life in the absence of implants?

Until 25 years ago neither of these valuable devices were readily available. But since then, high-tech health care has been moving forward. In fact, medical technology is advancing so fast that milestones are announced almost daily, and we are in the process of saying goodbye to exploratory surgery, infertility, drug reactions, wrinkled skin, and many other disruptive or devastating disorders.

Here is what health experts from a number of organizations consider the greatest medical advances of the recent past--and a revealing forecast of what to expect in this decade.

Wonder machines. Computers now provide images of the body based on various scanning techniques such as X-rays, radionuclides, ultrasound, and magnetic resonance imaging (MRI). These images, which are three-dimensional and even colored to highlight specific tissues, give physicians as much information as they could obtain through exploratory surgery on the stomach, chest, or brain.

Imagine being able to view an epileptic seizure in progress. At Johns Hopkins University in Baltimore, researchers are using another wonder machine to determine the precise location of brain lesions that cause such seizures--by "erasing" the bone that would otherwise hide the lesion.

The machine, which resembles a two-ton doughnut, uses positronemission tomography (PET) to mark a white-hot circular spot in the temporal lobe just above the ear. When the seizure ends, the spot disappears, and the area becomes a cool blue. Similar PET scans are being used to study heart attacks, stroke, and Parkinson's disease.

Even more mind-boggling, PET has the potential to document whether a person is having a hallucination (as in schizophrenia) or is feeling pain. It has been used by researchers at the University of California at Irvine to provide color pictures of brain cells at work thinking or reasoning.

Safer surgery. Not all medical equipment is large and imposing. Surgeons now use endoscopes that enter the body without requiring large incisions. A viewing tube is directed at the target and used as a guide through which tiny instruments are passed to perform gallbladder surgery, ulcer removal, or appendectomies, resulting in much shorter hospital stays.

Other "tiny tech" instruments include the "rotablator," which uses a diamond-tip drill spinning at 190,000 revolutions per minute to shave plaque, unclog arteries, and restore normal blood flow in patients with heart disease. Radioimmunoguided surgery can remove tumors so small that cancer surgeons cannot see or feel them.

"Anything can be implanted or transplanted, even brain tissue," says Arthur McFee, M.D., of the University of Texas Health Science Center. About 300,000 hip, finger, knee, and toe joints are implanted annually. In addition, elbows, wrists, and ankles can now be reinforced or replaced with plastics, ceramics, and metal alloys.

Lasers have also been used to zap trouble anywhere in the body with spellbinding speed and greater precision than knife surgery. They are particularly useful in hard-to-reach or delicate areas such as the eye and throat, where the operative field is small.

Extensive research is rapidly improving laser techniques in more than a dozen specialties to treat a wide spectrum of problems ranging from skin cancer to reproductive disorders and internal bleeding. At Cedars-Sinai Medical Center in Los Angeles, cardiologists have even unblocked arteries with lasers beamed through glass fibers thinner than a human hair.

Gene therapy. The medical technologies of the future, such as gene therapy, fetal surgery, and tissue cloning, promise to eclipse even the boom of the past 20 years--in miracles and cost. The dilemma: We still lack a way to measure the benefits against the overall cost, says William Cutler, research chief for the Employee Benefit Research Institute.

But even skeptics agree that genetically engineered drugs, when they reach their full potential, could revolutionize medicine. To date, the technique has been used to produce synthetic hormones and body chemicals to treat mostly metabolic disorders.

One example is synthetic insulin, which is used to treat diabetes and is obtained by gene splicing. Other substances produced in much the same way include human growth hormones to treat dwarfism in children, factor VIII (hemophilia), erthropoietin for severe forms of anemia, and interferon or interleukin to treat leukemia and several other cancers.

Though technically difficult genetic engineering is simple in theory. The gene that instructs cells to produce a hormone or chemical is identified by gene mapping, isolated, and inserted into bacterium or yeast. The bacterium is then cultured in vats so that it multiplies and produces large quantities of the hormone.

The process has led to advances in the understanding and treatment of cancer that were unimaginable a decade ago, says John Mendelsohn, M.D., chief of medicine at Memorial Sloan-Kettering Cancer Center in New York City. Other candidates for gene therapy include cystic fibrosis, sickle cell disease, phenylketonuria in newborns, muscular dystrophy, and Tay-Sachs disease.

Researchers who injected older men with synthetic growth hormone found they had fewer wrinkles and many other characteristics of men 20 years younger. "This is not a fountain of youth," cautions Daniel Rudman, M.D., of the Medical College of Wisconsin in Milwaukee. But similar treatment may prove beneficial for those whose muscles are wasting away or are recovering from hip surgery, stroke, or other debilitating diseases.

Staying Healthy. Yet despite the miraculous advances and high-tech medicine, nothing will benefit your health more than a few simple lifestyle changes. Extensive research in nutrition and exercise is gradually providing new insights into many puzzling disorders that have so far defied medical treatment.

"Our research has shown that by proper diet and exercise, you not only add years to your life, but prolong the duration of youth and middle age," explains Roy Wolford, M.D., professor of pathology at the UCLA School of Medicine.

A healthy mental attitude and eradication of childhood diseases also contribute to a greater portion of the population reaching their full potential. These trends are expected to cut in half the incidence of heart disease among the middle-aged in the next 10 years, adds Wolford.

HIGH TECH COMES HOME

The comforts of home combined with advanced medical technology--now, that's something we can appreciate. And it's becoming more of a reality every day. High-tech equipment and procedures now available for home use include:

* Prenatal monitoring. For mothers-to-be with difficult pregnancies it is possible to monitor the unborn baby and any unusual labor activity at home. If anything unexpected occurs, nurses and doctors are immediately alerted.

* Phototherapy. Babies who are born with "yellow jaundice" can now be treated at home with light therapy, thereby avoiding prolonged hospitalization and separation from parents and family.

* Diabetes testing. Simple procedures are available for the testing of blood sugar, allowing diabetic patients to monitor the progress of their therapy.

* Pacemaker monitoring. By electronic communication, physicians can follow the progress of patients who have a pacemaker to regulate their heartbeat.

* Intravenous (IV) therapy. Intravenous treatments, including fluids for hydration, nutrition, antibiotics, and cancer chemotherapy are routinely delivered in the home.

* Ventilators. Even patients who require mechanical support for breathing are now cared for at home.

And this is just the beginning. It's clear that "the future hospital is coming to the patient."