Imagine a world in which brain tumors are removed without cutting into the patient’s head, without a single drop of blood spilled.
Or a world where the massive internal bleeding that killed Princess Diana and Congressman Sonny Bono could have been treated at the scene of the accident, and their lives saved.
“It’s not that far away,” says University of Washington physicist Larry Crum. “This is not a Star Trek thing.”
The technology is called focused ultrasound surgery, but it’s not surgery in the traditional sense. There’s no scalpel involved, no sutures to stitch, no risk of complications from blood loss.
We’re used to thinking of ultrasound as producing the fuzzy images of a baby still in its mother’s womb. But now, scientists have found that by focusing an ultrasonic beam—roughly 10,000 times the power used for prenatal pictures—they can raise the temperature of cancerous tissue at the focal point to nearly boiling. Within seconds, the tissue dies.
Crum and other colleagues from around the world studying high-intensity ultrasound presented their research today at the Acoustical Society of America’s annual conference in Seattle.
The Magnifying Glass Effect
How does it work? Gail ter Haar, a physicist studying ultrasound surgery at the British Royal Marsden Hospital, explains it this way: Think about the days when you were a kid, hovering a magnifying glass over an object to burn the legs off a bug or singe the edges of a leaf.
Like the magnifying glass focusing the sun’s rays, ultrasound can be focused to heat tissue deep within the body.
“Just as with the leaf, you destroy cells within the focus area,” she says. “And anything outside that area is safe.”
It’s so precise in fact, that there’s a boundary of just six cells between the tissue that dies and tissue that lives—even more precise than a scalpel in the hands of a highly skilled surgeon.
Haar and her British colleagues are in the first phase of clinical trials testing the ultrasound treatment on liver, kidney and prostate cancers. So far they’ve used the focused ultrasound on 23 patients with large tumors and have been problem-free.
“We’ve found that in animal experiments, if we can cover the whole tumor, we can eradicate the cancer,” Haar says. “We don’t know yet if we’ll have the same results in humans. But it’s very exciting data.”
Another area of study is using ultrasound to stop bleeding in trauma patients.
University of Washington radiologist Dr. Stephen Carter says there’s a “Golden Hour” after someone is in a major accident with internal bleeding. If they don’t get help within the first hour, the injured will likely bleed to death.
But if you apply the ultrasound right to the bleeding spot, the heat can induce the blood to clot.
Enlarged Prostate the First U.S. Treatment
The day when American cancer patients can get ultrasound treatment to kill their tumors or paramedics carry ultrasound units to accident sites is still years away, possibly even a decade. But in October, physicists here were granted FDA approval to treat enlarged prostate glands.
The potential for such a market is enormous: nearly 50 percent of men over age 55 suffer from an enlarged prostate, which makes it difficult for them to urinate.
But as Carter points out, focused ultrasound has a vast number of uses.
The Navy is studying its potential use on the battlefield, because soldiers die from internal bleeding more often than anything else.
And even NASA is interested in the possibility of its use on the space shuttle. “Someday, they’re going to have a problem in space,” Carter says, “and there will be no place for them to go to get help.”
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