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Doctors perform the experimental light treatment

From Correspondent Rick Lockridge

MILWAUKEE (CNN) -- Katie Pedersen dreams of designing homes and of watching her beloved Green Bay Packers win another Super Bowl. The Milwaukee teen-ager is alive to pursue those goals because of her own courage and because of a magic wand of light that is helping her fight cancer.

Katie had a rare brain tumor. Aggressively malignant. The worst kind you could have. Doctors found it 10 years ago when she was 9. Surgeons tried repeatedly to remove it but it kept growing back.

There were complications. Radiation treatments burned her spinal cord, leaving her in a wheelchair. And still the tumor returned.  

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Katie was losing the battle, says one of her physicians, Dr. Glenn Meyer, a neurosurgeon who turned to photodynamic therapy -- the use of light to trigger the action of cancer- killing drugs. ( 249 K/5 sec. AIFF or WAV sound).

How it works

The experimental technology that saved Katie originated with NASA, in an experiment using light-emitting diodes (L.E.D.) to grow food in space.

Tests showed that when anti-cancer drugs are injected into the bloodstream and illuminated with a light source -- usually a laser, inserted by a surgeon -- the light triggers the drug, killing tumors more effectively than with conventional surgery.

When it works, it works well. But the drugs sometimes kill healthy cells and the lasers are dangerous, expensive and hard to use.

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So when NASA proposed a better "light trigger," a flexible, expandable light source first used in a crop-growing experiment aboard space shuttle Columbia, doctors at Children's Hospital of Milwaukee agreed to test it. And Katie, out of options, agreed to be the patient.

Surgeons removed as much of her recurring brain tumor as they could. They then injected light-sensitive drugs and inserted the NASA light-probe, expanding it to fill the cavity.

Unlike a laser, the NASA light generates less heat, can penetrate deeper into tumor tissue and kill the tumor without hurting the healthy cells.

The treatment is only successful with about a third of such patients and in Katie's case, it worked. ( 249 K/5 sec. AIFF or WAV sound)

Katie

The tumor has not recurred, says another of her doctors, neurosurgeon Harry Whelan. ( 249 K/8 sec. AIFF or WAV sound)

Katie, a straight-A student who endured six brain surgeries and still graduated on time with her high school classmates, won't say she's cured but she told CNN, "I feel like I am." ( 118 K/8 sec. AIFF or WAV sound)

The young woman's positive attitude after her experimental light treatment is accompanied by the smile of a survivor: simply luminous.