Diagnostic imaging technology is used by radiologists to diagnose and treat diseases.

The field of radiology can be divided into two types, diagnostic radiology and interventional radiology. 

Radiologists are doctors who specialize in radiology.

Diagnostic Radiology

Using diagnostic radiology, health care providers can see structures inside your body. 

Those who specialize in the interpretation of these images are called diagnostic radiologists. 

Using the diagnostic images, the radiologist or another physician can usually:

  • Find out what’s causing your symptoms
  • Keep track of how well your body responds to the treatment you are receiving for your condition or illness
  • Test for different illnesses, such as breast cancer, colon cancer, or heart disease

Computed Tomography (CT) Scan

Computed tomography (CT) scans use x-rays to create pictures of cross-sections of the body.

CT Scan Procedure

The patient will lie on a narrow table that slides into the center of the CT scanner.

The machine’s x-ray beam rotates around you once you’re inside the scanner. 

Spiral scanners can perform the examination without stopping.

Computers create separate images of the body area, called slices. 

They can be viewed on a monitor, stored, or copied to a disk. 

By stacking the slices together, three-dimensional models of the body area can be created.

While taking the test, you must remain still, since movement causes blurred images. 

You may be instructed to hold your breath for short periods of time.

A complete scan usually takes only a few minutes. 

A new scanner can take a picture of your entire body in less than 30 seconds.


A fluoroscopic image shows moving organs, tissues, or other internal structures in real time. 

A standard x-ray is like a still photograph. 

With fluoroscopy, it’s like watching a movie. It shows the body in action. 

The cardiovascular (heart and blood vessels), digestive, and reproductive systems are among them. 

Your health care provider can use the procedure to evaluate and diagnose a variety of conditions.

Magnetic Resonance Imaging (MRI)/Magnetic Resonance Angiography (MRA)

MRI scans create body images with the help of powerful magnets and radio waves. They do not use ionizing radiation (x-rays). Slices are single images from an MRI. These can be saved on a computer or printed. A single exam produces thousands of images.

MRI Procedure

Depending on the procedure, you may be required to wear a hospital gown or clothing without zippers or snaps (such as sweat pants and a t-shirt). Certain types of metal can cause blurry images.

The patient lies on a narrow table that slides into a large tunnel-shaped scanner.

A special dye (contrast) may be required for some exams. 

You will usually receive the dye through an IV in your hand or forearm before the test. 

The dye allows the radiologist to see certain areas more clearly.

In order to study various areas, coils may be placed around the head, an arm, a leg, or some other part of the body. 

These assist in sending and receiving the radio waves and enhance the quality of the images.

The person operating the machine will watch you from another room during the MRI. 

This test usually takes 30 to 60 minutes, but it may last longer.


Mammograms are x-ray pictures of the breasts. They help detect breast cancer and tumors.

Mammography Procedure

It will be necessary for you to remove your clothing from the waist up. 

You will be provided with a gown. 

The type of equipment used will determine whether you sit or stand.

Breasts are placed one at a time on a flat surface that contains an x-ray plate. 

The breast will be compressed by a device called a compressor. 

This will help flatten the breast tissue.

Images of the x-ray are taken from various angles. 

You may be asked to hold your breath during each image.

After The Procedure

You may be asked to return for more mammogram images at a later date. This does not necessarily mean you have breast cancer. There may be a need to recheck an area that was not clearly visible during the first test.

Nuclear Stress Test

Nuclear stress tests are imaging tests that use radioactive material to measure how well blood flows into the heart muscle at rest and during activity.

Nuclear Stress Test Procedure

The test is performed in a medical center or at the office of a healthcare provider. 

It is performed in stages:

  • An intravenous line will be inserted.
  • One of your veins will be injected with a radioactive substance, such as thallium or sestamibi.
  • After you lie down, you’ll have to wait for 15-45 minutes.
  • With the help of a special camera, you will be able to see how the substance traveled through your blood and entered your heart.

After that, most people will walk on a treadmill (or pedal on an exercise machine).

  • As the treadmill starts moving slowly, you will be asked to walk (or pedal) faster and at an incline.
  • You may be prescribed a medicine called a vasodilator (such as adenosine or persantine) if you can’t exercise. Vasodilators widen your heart arteries.
  • You may be prescribed a medicine (dobutamine) that makes your heart beat faster and harder, just like when you exercise.

Throughout the test, your blood pressure and heart rhythm (ECG) will be monitored.

The radioactive substance is again injected into a vein when your heart is working as hard as it can.

  • You will have to wait 15 to 45 minutes.
  • Your heart will be scanned again by the camera and pictures will be created.
  • You may be allowed to get up and have a snack or drink while sitting at the table or chair.

The provider will use a computer to compare the first and second set of pictures. 

Using this method, you can find out if you have heart disease or if your heart disease is getting worse.

Thyroid Scan

A thyroid scan uses a radioactive iodine tracer to analyze how the thyroid gland functions. 

It is often done in conjunction with a radioactive iodine uptake test.

Thyroid Scan Procedure

You are given a pill that contains a small amount of radioactive iodine. 

The iodine in the pill collects in your thyroid after you swallow it.

The first scan is usually performed 4 to 6 hours after taking the iodine pill. 

Typically, another scan is done 24 hours later.

During the scan, the healthcare provider will have you line on your back on an adjustable table.

Your chest and neck will be positioned directly under the scanner.

The healthcare provider will ask you to lie still so that the scanner can get a clear image.

The scanner will detect the location and the intensity of the radiation given off by the iodine. 

A computer will then display the images of the thyroid gland.

Bone Scan

A bone scan is an imaging test used to diagnose bone diseases like bone cancer, and monitor the severity of the disease.

Bone Scan Procedure

In order to perform a bone scan, a very small amount of radioactive material (radiotracer) is injected into a vein. 

As the substance moves through the blood, it is absorbed by the bones and organs. 

As it wears off, it emits some radiation. 

Cameras are used to detect this radiation as it slowly scans your body. 

The camera measures how much radiotracer collects in the bones.

An x-ray of your bones may be taken after the radioactive material is injected and again three to four hours later, when it has accumulated in your bones, to see if you have a bone infection. 

This is referred to as a three-phase bone scan.

To evaluate whether cancer has spread to the bone (metastatic bone disease), images are taken only after the 3- to 4-hour delay.

The scanning portion of the test will last about an hour. 

During that time, the scanner’s camera will be moving above and around you. 

You may have to adjust your position.

To prevent the material from accumulating in your bladder after you receive the radiotracer, you may be advised to drink extra water.


As with visible light, X-rays are a form of electromagnetic radiation.

Each x-ray particle is sent through the body by an x-ray machine. 

A computer or film records the images.

  • Dense structures will block the majority of the x-ray particles, and will appear white on the images
  • Metal and a special dye used to highlight portions of the body (called contrast media) will also appear white.
  • Structures that contain a lot of air will be black, and muscles, fat, and fluid will appear as varying shades of gray.

X-Ray Procedure

A hospital radiology department or a doctor’s office performs the test. 

Depending on the type of x-ray being taken, you may be positioned differently. 

You may need a variety of x-ray views.

During an x-ray, you must remain still. 

Motion can result in blurry images. 

When the image is being taken, you may be asked to hold your breath or not move for a few seconds.

Positron Emission Tomography (PET) Scan

PET scans are a form of imaging test. 

It uses a radioactive substance called a tracer to detect disease in the body.

Positron emission tomography (PET) scans provide information about organs and tissues.

MRIs and CT scans are not the same. 

These tests reveal the organ’s structure and blood flow to and from it.

The PET/CT machine is a machine that combines the PET and CT images, and is more commonly used.

PET Scan Procedure

PET scans use a small amount of radioactive tracer. 

The tracer is given intravenously (IV). 

The needle is usually inserted on the inside of your elbow. 

Tracers travel through your blood and collect in your organs and tissues. 

This allows the radiologist to see certain areas more clearly.

It will take a while for the tracer to be absorbed by your body. It usually takes one hour.

After that, you will lie on a narrow table that slides into a large tunnel-shaped scanner. 

The tracer sends signals to the PET. A computer converts those signals into 3D images. 

The images are displayed on a monitor for your health care provider to see.

During the test, you must remain still. 

Movement can blur images and cause errors.

Depending on what part of the body is being scanned, the duration of the test will vary.


The use of ultrasonic imaging produces images of organs and structures inside the body using high-frequency sound waves.

Ultrasound Procedure

Images created by an ultrasound machine can be used to study organs within the body. 

Sound waves are sent out by the machine, and they reflect off body structures. 

The waves are then received by a computer and used to create a picture. 

Unlike x-rays or CT scans, this test does not use ionizing radiation.

Ultrasound or radiology departments perform the test.

  • The test will require that you lie down.
  • On the area to be examined, a clear, water-based gel is applied. This gel facilitates the transmission of sound waves.
  • The area being examined is probed with a handheld instrument called a transducer. If other areas need to be examined, you may be required to move.

Interventional Radiology

Interventional radiologists are doctors that use imaging tools such as CT scans, ultrasound, MRIs and fluoroscopy to guide their procedures.

The imaging helps your doctor insert catheters, wires, and other small instruments and tools into your body. 

In most cases, this results in smaller incisions.

This technology can be used by doctors to diagnose or treat conditions in nearly any part of your body without having to look inside your body through a scope (camera) or performing open surgery.

The main issues that interventional radiologists treat are cancers, tumors, blood clots, fibroids in the uterus, back pain, liver diseases, and kidney disease.

In most cases, the doctor will make no incision or only a very small incision. 

After the procedure, you are rarely required to stay in the hospital. 

The majority of people only require moderate sedation (relaxation medicines).

Radiology Frequently Asked Questions

Radiologists are medical doctors who specialize in diagnosing and treating injuries and diseases through radiological procedures (exams/tests) such as X-rays, computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, positron emission tomography (PET), and ultrasound.

CT scans can detect bone and joint problems, such as complex fractures and tumors. 

CT scans can detect conditions like cancer, heart disease, emphysema, or liver masses. 

These scans can also show internal injuries and bleeding, similar to those caused by car accidents.

Radiography or X-ray and fluoroscopy are similar procedures. 

Radiography creates a static image of the internal structure of a body with gamma rays, while fluoroscopy produces moving images of the inside of the body with fluoroscopy.

In general, fluoroscopy is a safe procedure, but burns and radiation-induced injuries to the skin can occur. 

A CT scan, on the other hand, is still a snapshot of a piece of the body. 

X-rays are used to help your doctor view important organs.

Both types of scans have similar uses, but they produce different images. 

An MRI scan uses strong magnetic fields and radio waves, whereas a CT scan uses X-rays. 

CT scans are less expensive and more common, but MRI scans produce more detailed images.

An MRI scan does not have any known side effects. 

The benefits of an MRI scan stem from its precise accuracy in detecting structural abnormalities of the body. 

Any metallic materials within the body must be disclosed to the MRI staff prior to the examination.

A mammogram is an X-ray image of the breast. 

Mammograms are used to check for early signs of breast cancer. 

Mammograms are the best way for doctors to detect breast cancer early, sometimes up to three years before symptoms develop.

Nuclear stress tests are imaging tests that use radioactive material to measure how well blood flows into the heart muscle at rest and during activity.

The test typically takes three to four hours.