UCSF Children's Hospital | Alejandro Sanchez

For nearly two years, he feared pain so excruciating he thought his head would burst. Only 16 years old, Alejandro worried that a brain hemorrhage would leave him disabled or dead.

It was in March 1998, when a sudden attack of dizziness, followed by a severe headache and nausea, struck the teenager. Carmelita Sanchez-Ortega rushed her son that afternoon to John Muir Hospital in Walnut Creek, where tests revealed that blood, probably from a ruptured vessel, had leaked into surrounding brain tissue. Doctors there suggested that Alejandro be taken to UCSF Medical Center, a leader in pediatric neurosurgery.

After an ambulance ride across the bridge and a series of more tests, the UCSF team diagnosed the culprit — a walnut-sized mass of engorged and tangled blood vessels in Alejandro's brain. Alejandro likely was born with the condition, known as arteriovenous malformation (AVM). Over the years, the blood vessels thickened and snarled, unable to travel on a normal pathway. Much like a small ball of string, the vessels wrapped around each other. In AVMs, the vessels may leak or eventually rupture, causing headaches, seizures or stroke-like damage.

Often, brain surgery is performed to remove the tangled mass. In Alejandro's case, the AVM was buried in the right thalamus, deep in the core of the brain and where nerve fibers relay crucial signals to and from the sensory parts of the organ.

"We were shocked at first, and then so afraid of what the condition would do to him," said Carmelita.

Dr. Michael Lawton, director of UCSFs Cerebrovascular Disorders Program, decided conventional brain surgery was too risky for Alejandro, because of the location and largeness of the AVM. If not treated, such AVMs have a 70 percent to 80 percent chance of hemorrhaging. And each hemorrhage, said neurosurgeon Dr. Michael McDermott, carries a 20 percent risk of disability and 10 percent chance of death.

UCSF offered Alejandro an option -- the Gamma Knife, which actually is not a knife at all. The high-tech tool fires high doses of radiation at its target — whether a deep-seated brain tumor or AVM — with such pinpoint accuracy that only diseased brain tissue is destroyed. This "radiosurgery" leaves surrounding healthy tissue intact.

UCSF was the first in Northern California to offer the Gamma Knife in 1991 and has since treated more than 1,500 patients, including Alejandro, the oldest of the Santa Rosa family's four children.

In the two months between the time Alejandro was first rushed to the hospital and his scheduled Gamma Knife procedure, the headaches and dizziness worsened. Alejandro was forced to miss school, was sidelined from playing soccer and even his favorite hobbies — drawing and painting — were too difficult.

In May 1998, Alejandro was back at UCSF to go under the Gamma Knife. Imaging techniques — computerized tomography (CT), magnetic resonance imaging (MRI) and angiography — were used together with special computer-assisted instruments to provide a three-dimensional view of Alejandro's AVM and the surrounding parts of the brain. McDermott, co-director of the UCSF Gamma Knife program, led a team that included medical physicists and specially trained radiosurgery nurses.

For the procedure, Alejandro was fitted with a hat-brim-like "stereotactic" frame attached to his skull with needle-thin screws. The frame immobilizes the head for imaging tests and later acts as a grid for targeting the malformed vessels.

The Gamma Knife includes a helmet — which looks like a large hair dryer — with 201 holes that act as portals for radioactive cobalt. Through these holes, gamma rays — a form of radiation similar to X-rays — are emitted. Each of the 201 rays is harmless alone, but when they converge on their target they can obliterate an AVM over a two-to-three year period. The Gamma Knife is so precise that all 201 beams can hit simultaneously a target less than the size of a pea.

Alejandro was placed on the couch of the Gamma Knife, his head positioned in the helmet, with its 201 holes, according to target coordinates determined by the three-dimensional images. From an outside computer panel, the team fired the rays that they hoped would cure Alejandro.

The procedure was over in minutes. It was considered surgery, but there was no incision and no bleeding.

For brain tumor patients, the results or success of the Gamma Knife are known quickly and the medical team can decide the next step. For AVMs, the Gamma Knife radiation does not destroy the vessel malformation outright, rather it triggers cells in the vessels' lining to proliferate, and within two to three years the abnormal vessels often disappear.

Soon after the procedure, Alejandro's headaches and dizziness became less frequent. And after a year and a half the symptoms were gone. School, soccer, art and good-natured two-way teasing with his brothers and sisters were back on his activity list. He felt good again, but the fear and worry of a time bomb in his brain, however, remained.

In 2000, two weeks before Christmas at a visit with McDermott and the UCSF team, tests showed no signs of the tangled vessels in his brain. "I was so happy and thankful," said Carmelita. "I wanted to give everyone gifts right there. Everyone on the team had been so good to us."

Alejandro will need another follow-up test to make sure the AVM is indeed gone. But this winter he received the present he really wanted — peace of mind.

For more information about the UCSF Gamma Knife Radiosurgery Program, call (415) 353-7500.