Just as the newer medicines may be more effective at fighting an illness than the old standby penicillin, the newer types of imaging are more effective at seeing what is going on in the body, and thus may be more useful to the physician. In fact, the new and different ways to see into the body are reflected in the name of the discipline. What used to be called the X-ray lab is now called the Diagnostic Imaging Department.

Looking inside the body
Diagnostic imaging at Bigfork Valley

At Bigfork Valley Hospital, Brenda Schmitz is head of diagnostic imaging, and she sees exciting things happening. On the top of her wish list was to make it easier for area women to have a quality mammogram. That’s now happened with the installation of new state of the art equipment.

Also new is a portable “C” arm fluoroscope, a piece of equipment that can be moved right to the orthopedic operating table. Those represent two imaging techniques in the diagnostic arsenal available to the hospital on site; techniques which also include bone densitometry and CT scanning. In addition, a mobile MRI unit visits the hospital weekly, the Minnesota Heart Institute provides echocardiograms weekly and ultrasounds are administered twice a week.

“These imaging techniques are important tools for the doctor,” said Bigfork Valley CEO Dan Odegaard. “And it’s important to us to have these tools available here in Bigfork so our patients don’t have to travel long distances to take advantage of them.”

Why so many different kinds of tests? Each test has an advantage for a different kind of situation. For instance, a simple bone break might be easily seen on a traditional X-ray. But what if something is hidden on the other side of the bone? A CT scan uses a X-ray unit that moves around the body to look at different angles.

And what if the doctor is interested in the soft tissue around the bone? Soft tissue does not show up well on X-rays, but it does on MRI.

It sounds like magic. But it is the everyday electron behind most imaging techniques.

Electrons exist at different energy levels around a nucleus of an atom. Those energy levels are very specific and depend on what kind of atom it is. When electrons move to different energy levels, they give off or gain just the amount of energy between the energy levels.

If that energy drop is large, it gives off a high energy packet that is called an X-ray.

As the X-ray moves through the body, it might be absorbed - but only by a material that absorbs that energy level well (like the calcium in bone). In that case, the X-ray will not be able to pass through it unless there is a break. The break will show up clearly on the film negative that records where X-rays hit it. A bone densitometry scan is an X-ray that is tailored to look at the calcium content of the bone, usually in the lower back or hip area.

A patient may be asked to drink a contrast media, like a barium liquid. This shows up on X-rays because it, too, absorbs them well.

Sometimes it is helpful to watch as the contrast media moves through the body, and this is done through fluoroscopy. The X-ray hits a fluorescent screen which allows continuous images to be displayed.

In a CT scan, the X-ray “camera” moves around the body, taking hundreds of images. Those images are put together by a computer, giving a complete view - even if part of the image lies behind an area which would normally block an X-ray.

In an MRI, the patient also lies in the middle of a scanner. The technology, however, is different. Using a magnetic field many times stronger than that of the earth, the machine aligns the magnetic fields of the individual hydrogen atoms in the body. A pulse of radio waves to a specific part of the body is absorbed by the hydrogen atoms in their spins, and when the radio waves stop, the hydrogen atoms gradually return, releasing energy that can be “seen.” The MRI scan is focused on a point, and is able to distinguish different types of tissue. It can integrate many data points to make either two- or three-dimensional images.

Like its name, ultrasound imaging uses sound waves instead of electromagnetic waves. And like sonar, it relies on reflection of sound waves as they travel through different types of material. The waves are reflected back at each boundary - for instance the boundary between soft tissue and bone - and return at different speeds depending on the kind of tissue they are passing through. The computer uses the time it takes for the echo to return and the intensity of its signal to produce a picture. How long does it take an echo to return? Don’t blink, it’s usually measured in millionths of a second.

An echo-cardiogram is an ultrasound tailored to look at the heart. Using doppler techniques, it can evaluate blood flows and show the information in color.

What’s next? Technology is constantly producing new ways and less invasive ways to show what is going on in the body. It also is doing it faster and more accurately. What could be next? There are many articles on the promise of nanotechnology, the science of structures on the molecular level. Perhaps someday diagnostic machines will be taking up close pictures - while circulating in our bloodstreams!

This article was compiled from both interviews and internet resources, including the web sites howstuffworks, netdoctor.co.uk and mywebmd.com.