There's a Scan for That? Medical Imaging 101

Modern diagnostics include medical scans that give your doctor a way to see the inside of your body without cutting you open. Medical imaging scans have made it much easier for most patients to get a diagnosis and the right treatment without necessarily having to undergo surgery. Medical imaging is a huge advantage because exploratory surgery can sometimes be costly and potentially dangerous.

Surgery is costly because you have to pay for the operating room, the anesthesia, the anesthesiologist and the surgeon, the nurses and surgical assistant. Surgery is potentially dangerous because, with any surgery, there is a risk of infection, heavy bleeding, and a bad reaction to the anesthesia, as well as the chance the incision won’t heal or that something else inside your body gets damaged during the surgery. On top of all that, you also have the recovery time, which could take several days or weeks.

The Benefits of Medical Imaging Scans vs. Other Tests

Many medical scans are non-invasive, which means they happen outside your body, and in some cases you don’t even need to remove your clothing. This means you won’t need anesthesia, and won't run the risk of infection or other issues associated with surgery. Also, if there is any recovery time, it’s usually a matter of minutes or hours, instead of days or weeks.

Types of Scans

Medical scans fall into four major categories: radiological, nuclear, magnetic, ultrasound, and endoscopic.


Radiological scans use some form of x-rays to get an image.

X-rays were first introduced as a diagnostic tool in the early 1900s. X-ray images were originally recorded on a film cartridge and required a long exposure time – sometimes upwards of 11 minutes. Today the images take seconds and are quickly transferred digitally to a computer screen or printed out onto film.

Standard x-rays take a two-dimensional image and work best on bone and other dense materials. For example, if you swallow a quarter, a traditional or standard x-ray can be used to see where it is in your digestive tract. X-rays can also be used to help diagnose lung diseases because tumors and infections show up as cloudy areas on the x-ray.

More advanced X-ray techniques include CT (computed tomography) scans and mammograms.

Both Mammograms and CT scans takes multiple images of the structures inside your body. CT scans can diagnose broken bones, just like a standard x-ray, but they can also diagnose cancers, blood clots, internal bleeding and heart disease. For the CT scan to effectively diagnose more than broken bones you may need to ingest a high-contrast material or the technician might inject it via IV. The high-contrast material makes soft structures, like blood vessels, show up better on the CT scan.

Mammograms are specifically designed to detect tumors and other abnormalities in breast tissue, and usually do not require a high-contrast material.

Because x-rays involve radiation exposure, pregnant women are advised to avoid them. Others, particularly children, should also limit the number of CT scans they undergo.


Nuclear medicine includes diagnostic scans that involve radiation. Instead of the machine emitting radioactive rays, you ingest a radioactive substance, called a tracer. You might drink the substance or a technician can inject it into your body via IV.

When you take the tracing substance, it collects in your tissues, and the camera detects it. The image can be projected onto a monitor or TV screen where your doctor can view it. Nuclear medicine scans detect cancers and infections, and also allow your doctor to see your organs working in real time.

The PET (Positron Emission Tomography) scan is one type of nuclear medicine scan.

As with the x-ray, pregnant women are advised to avoid these scans.


The MRI (Magnetic Resonance Imaging) uses high-powered magnets and radio waves to take diagnostic images. MRI scans can be used to diagnose a variety of conditions, but they work best for diagnosing abnormalities in the brain and spinal cord.

Because the MRI uses magnets, people with metal and electronic appliances, such as pacemakers, are advised to avoid them. People with metal implanted in their bodies, either surgically or from an accident or mishap, should also avoid MRIs. Finally, although the MRI process does not use radioactive materials, pregnant women are also advised to avoid them.


Ultrasounds use sound waves to diagnose abnormalities in soft tissue, like the heart, kidneys, and other organs. The sound waves bounce off the organs and structures and create an image on the screen. They work best on structures that are hollow or have cavities because the sound waves will show if there is a growth inside the cavity.

Because the ultrasound does not use radiation, they can safely be used on pregnant women to detect and chart the growth of the fetus.


Endoscopic medical imaging uses a tube with a very small camera attached to take images of the inside of the body. The endoscope can show growths, lesions, and abnormalities as well as the general function of the organ. Endoscopes are usually inserted through the mouth or anus to view the lungs or the stomach, upper digestive tract, or colon. A doctor can also make an incision and use an endoscope view the inside of a joint or of some internal organs, like the gall bladder.

The technician has to stick something inside your body, so endoscopy is considered a minimally-invasive procedure and might require a mild sedative to keep you relaxed and still during the procedure.

Because the endoscopic procedure does not use radiation, pregnant women can undergo the procedure as long as their doctor determines that the procedure will not interfere with the fetus.

Have specific questions?

All Article Categories

Suggested Doctors

Sorry, there are no matching doctors in your area
Please choose a different location



See more Suggested Doctors

Recently Asked Questions