A boost to radiation Machine allows for better treatment
Al Musella's Comments: (This is his personal views and are not necessarily the views of the Musella Foundation!)
Posted on: 01/19/2005
A boost to radiation; Machine allows for better treatment
health & fitness
By DAVE NORDSTRAND
The Salinas Californian
SCOTT MACDONALD/THE SALINAS CALIFORNIAN
Dr. Kevin Fisher, a radiation oncologist at the Salinas Radiation Oncology Center, stands Monday with the new Siemens ONCOR linear accelerator, used to deliver a focused radiation treatment called intensity modulated radiation therapy.
SCOTT MACDONALD/THE SALINAS CALIFORNIAN
Michael Hannner, chief therapist at Salinas Radiation Oncology Center, uses a computer displaying CAT scans used in a new type of radiation.
A new $1.5-million linear accelerator makes life tougher on tumors and easier on the Salinas-area patients who have them.
"This machine represents a major breakthrough in terms of the mechanics of giving radiation to the parts where it's critical," Dr. Kevin Fisher said.
"This is the next major frontier."
Fisher is a radiation oncologist at Salinas Radiation Oncology Center, 1069 Los Palos Drive. It's part of Salinas Valley Memorial Healthcare System.
He works with the center's centerpiece, the ONCOR Linear Accelerator.
It arrived six months ago, joining the lineup of high tech medical devices increasingly arrayed in the Salinas area.
In radiation oncology, X-ray beams, mostly, are aimed at malignant tumors in an effort to shrink and destroy them.
In the older technology, all the radiation "arrows" were fired at the same intensity.
En route to its tumor target, the radiation often damaged healthy tissue. Radiation for a lung tumor, for example, damaged a healthy esophagus. Radiation for prostate cancer damaged the rectum.
"The new technology lets us better isolate that prostate, so there's less damage to the rectum," Fisher said. "Side effects and toxic effects that could last a lifetime are reduced."
A higher and more effective dose is more safely delivered.
"It's especially beneficial delivering radiation to a tumor close to vital organs or other tissues that are highly sensitive to radiation," said Dr. Esmond Chan, also a radiation oncologist at the center.
One patient, a young man, had a tumor at the front of his brain. A neurosurgeon removed most of the tumor.
Without radiation, though, there was a high chance of it returning. Because it sat near the right eye, the challenge was to deliver radiation without damaging his vision.
"We can now skirt those sensitive nerves and may be able to spare his sight," Fisher said. "In the past, we took a big chance of making him blind."
The accelerator is cutting edge in the way it integrates computer technology with mechanical function.
Treatment planning starts with CT scans, said Michael Hanner, chief therapist.
"That's what we plan from," he said.
An image of a brain tumor appeared on his computer screen. Hanner rotated it in a three dimensional field.
The images showed the size and thickness of the target area and the density of the surrounding tissues.
Key to the accelerator's efficiency is IMRT, intensity modulated radiation therapy. It enables "dose sculpting," the ability to wrap a dose of radiation around a tumor.
The head of the accelerator contains 82 mechanical leaves, each attached to a motor, each able to move to commands. The leaves shape and reshape the radiation into required configurations.
"That allows us to do IMRT practically," Hanner said.
Using the software, the operator can program in the angle of the beam, the shape of the radiation field, how long the beam is to last and other data to include a log of the patient's treatment.
"All the parameters necessary to treat the patient," Hanner said.
Say that 150 units of radiation from a given direction for a given patient are required. The accelerator makes sure the patient gets only that dose, Fisher said.
"Human error is eliminated," he said.
Originally published Wednesday, January 19, 2005
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