New imaging technology alloiws a visual journey inside our bodies.

What lies beneath



What appears to resemble an illustration for a medical textbook is actually a CT scan of a living person's carotid arteries.


This image of a brain aneurysm is the product of a CT scan.


An MRI image produces an equally detailed picture of person's foot.


This image of the arterial network in the lower body is the product of a CT scan.


Paul Conklin.

WALLA WALLA - Forty-four years ago, the science-fiction film "Fantastic Voyage" envisioned what it would be like if a team of people in a submarine could be shrunk to the size of a microbe and sent sailing through a human body.

According to the film (which won an Academy Award for its visual effects), the sights would be pretty amazing. Now fast forward to 2010, where technology is allowing doctors to peer into people with almost the same perspective, minus the miniature submarine. (Also minus Raquel Welch, but that's neither here nor there.)

"The whole idea is to try to determine what's going on inside you without cutting you open," said Paul Conklin, director of diagnostic imaging for Providence-St. Mary Medical Center.

The ability to noninvasively "look" inside a patient started in 1895 with the first X-ray image. Matters took a quantum leap forward in the 1970s with the development of two new technologies, computerized axial tomography and magnetic resonance imaging. The first fuses computers with X-ray radiation to produce 3-D views of the body while the second employs powerful magnetic fields to see beneath the skin.

Both are now in standard use, and both technologies are improving. The newest example arrived at Providence St. Mary Tuesday as a massive crane gingerly lifted a new, nine-ton MRI machine, then lowered it into the hospital's radiology department.

The hospital is also adding a new, faster CAT scanner which can take 64 "slices" through a body in a half-second. "I can (image) a heart in about 11/2 seconds," Conklin said.

These latest machines will not replace the hospital's present MRI or CT equipment.

What the new gear will do is give doctors more tools to work with. "Each modality serves a different purpose," Conklin said, or, to put it another way, "each tool in the arsenal addresses a specific task."

But new does have its advantages, said Conklin and Dr. Brad Johnson, medical director of diagnostic imaging.

The latest MRI unit is rated at 3 teslas, twice as powerful as the hospital's present 1.5 tesla unit. (A "tesla" is a standard unit for measuring the strength of a magnetic field. A magnetic field of 1 tesla is about 30,000 times as powerful as the Earth's magnetic field.)

"As we started to do imaging using magnetic fields, (manufacturers) made the fields as large as they could," Johnson said. "Stronger fields give a better image, so there's been a push to go to higher field strengths."

Another advantage is because the field is so much stronger, "you can move the detectors further away without losing the image quality," Johnson said.

The practical upshot of this is the doughnut-shaped detector ring patients must pass through can now fit large-framed people and people who are claustrophobic.

The latter folks are no joking matter, Johnson said.

"A significant number of people won't undergo an MRI because of claustrophobia.

"About 10 percent of the patients we do with sedation, but that doesn't count the number who won't even consider undergoing an MRI in the first place," he said.


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