Medical Imaging vs. Radiology: What’s the Difference?


Unless you are a trained medical professional, you may have trouble understanding the difference between medical imaging and radiology. It’s sometimes hard to differentiate between two similar ideas or practices within the medical field, and people often get these terms confused.

CT scan image

 

In this article I will describe each term in depth and explain how they differ.

While radiology and medical imaging are certainly very closely related, they are not the same thing. Radiology is the science of X-rays and other high-energy radiation technologies for the diagnosis and treatment of different conditions and diseases. Medical imaging technologies, on the other hand, are visual representations of the inside of the body.

Radiology, however, is not limited to just one area of practice. Below, I will highlight several different specialties and subspecialties that utilize different medical imaging techniques for various purposes.

Is Medical Imaging and Radiology the Same?

While medical imaging and radiology are very closely related and often are confused with each other, they are not the same thing. Radiology is a specific field of medicine, while medical imaging is a technology used by radiologists.  Medical imaging may be used by radiologists to monitor, diagnose, or treat various conditions within the body in a non-invasive way. Different types of radiologists specialize in and utilize different medical imaging technologies, depending on what field of medicine they’re in and what kind of patients they treat.

These technologies are used so physicians can view the inside of the body without needing to perform any exploratory surgeries. According to the FDA, this is crucial in allowing the radiologist and other doctors on a patient’s care team to learn and monitor information related to the diagnosis and treatment of diseases or injuries. It also allows physicians to check how the body is responding to previously administered medical treatment.

What is Medical Imaging?

The term “medical imaging” refers to a branch of technologies that allow a radiologist to diagnose, treat, or monitor diseases or injuries inside the body. It can also be used to keep track of the body’s response to a previously administered or ongoing medical treatment.

According to NPS MedicineWise, medical imaging includes technologies such as:

  • X-rays
  • Ultrasounds
  • CT Scans
  • MRIs
  • SPECT Scans
  • PET Scans

Each of these technologies is best suited to different purposes, depending on the patient’s condition and what part of the body the radiologist needs to view.

Types of Medical Imaging Technologies

There are many different types of medical imaging technologies that radiologists use. Here is what you can expect with each one:

X-Rays with Ionizing Radiation

X-rays are typically used to provide images of the bones inside your body. They use ionizing radiation and are most often used to tell if you have a bone break or sprain. They can also detect arthritis, osteoporosis, infections, cancer, or digestive problems.

X-rays are relatively quick and simple, taking just a few seconds to complete. Usually, an x-ray will be done while you are either standing or sitting, but you might be required to lay down in some instances.

CT Scans with Ionizing Radiation

CT scans take a series of X-rays to create images of the cross-sections within the body. Like x-rays, they use ionizing radiation and can detect broken and fractured bones, infections, and cancers. According to the University of Virginia, CT scans can:

  • Detect traumatic injuries
  • Detect vascular and heart diseases
  • Guide biopsies

While x-rays are typically done while you’re sitting or standing, and are only done while laying down in certain circumstances, a CT scan requires you to lay on a table that slides into a tube, rotating around you while it takes x-rays of your whole body.

Like x-rays, CT scans are fairly quick procedures. They take about 15 minutes to complete, though this can vary based on your condition.

MRIs with Magnetic Waves

Like CT scans, you’ll be required to lay on a table that slides into a scanner during an MRI, though MRI machines are usually more narrow and deeper than CT scanners. MRI machines use magnetic waves, and you may hear tapping or banging while the MRI is used.

These scans produce detailed images of organs and tissues. According to UVA, MRIs can detect and diagnose serious conditions and problems including:

  • Aneurysms
  • MS
  • Strokes
  • Spinal cord issues
  • Tumors
  • Joint and tendon injuries

Ultrasounds with Sound Waves

Most people are familiar with ultrasounds in terms of monitoring a pregnancy and checking an unborn baby’s development. However, ultrasounds also have a number of important diagnostics uses. The University of Virginia claims ultrasounds can guide biopsies and diagnose things like:

  • Blood flow problems
  • Joint inflammation
  • Breast lumps

As the name suggests, ultrasounds use sound wave technology to view different organs within the body.

When you get an ultrasound, the technician will first apply a gel to your skin to reduce the amount of air between your skin and the ultrasound probe. This is done because the ultrasound waves may be affected while traveling through the air, skewing the image they provide. The technician will then move the probe around the area until they find the area they need to see.

PET Scans with Radiotracers

Positron emission tomography (PET) scans are one of the more complicated medical imaging technologies. They use radioactive drugs called “radiotracers” to show organ and tissue function throughout the body.

Before you undergo a PET scan, you’ll need a dose of radiotracers. The radiologist will either give you a radiotracer pill to swallow or an intravenous injection of the substance prior to the scan, and this will allow the scanner to read the radiation given off by it.

PET scans can be used to diagnose a variety of serious conditions, including:

  • Cancer
  • Heart diseases
  • Alzheimer’s
  • Parkinson’s
  • Epilepsy

The machine used to administer a PET scan is similar to those used for CT scans and MRIs.

SPECT Scans with Radiotracers

Single-photon emission computerized tomography scans, or SPECT scans, are a type of nuclear imaging scan similar to PET scans. They produce images that show how well your organs work together, like how well your blood flows throughout your body or what areas of your brain are the most active.

According to the Mayo Clinic, SPECT scans can monitor and diagnose:

  • Heart disorders
  • Brain disorders
  • Bone disorders

Before the SPECT scan begins, you will be given an intravenous dose of a radiotracer similar to that administered during a PET scan.

Once your body has absorbed the substance, you will be scanned in a machine similar to an MRI machine. The length of time it takes can vary depending on your condition, but it’s typically a longer process than most other medical imaging procedures (Mayo Clinic).

What is Radiology? What are the Different Types?

Radiology is a branch of medicine that uses radiation technology, including medical imaging, to diagnose, treat, and monitor diseases and injuries. In some cases, radiology is also known as roentgenology.

Physicians who practice radiology are known as radiologists. They may specialize in one of three areas:

  • Diagnostic Radiology
  • Interventional Radiology
  • Radiation Oncology

Within the broader area of radiology as a whole, there are three distinct areas in which radiologists will practice, according to the American Board of Radiology. These areas include:

Diagnostic Radiology: Diagnosing and Treating Disease

As the name suggests, diagnostic radiology is mainly concerned with the diagnosis and treatment of disease. Diagnostic radiologists use all of the medical imaging technologies listed above in their work.

There are many subspecialties that diagnostic radiologists may work within. Some of these include neuroradiology, pain medicine, and pediatric radiology.

Interventional Radiology: Using Medical Imaging for Treatment

Interventional radiologists perform imaging, image-guided procedures and can diagnose or treat conditions within:

  • The abdominal region
  • The pelvic region
  • The thorax
  • The extremities

They may utilize therapies such as embolization, angioplasty, drainage, and stent placement in their work.

Interventional radiologists may subspecialize in a variety of subjects, including nuclear medicine and pediatric radiology.

Radiation Oncology: Treating Cancer with Radiation

Radiologists who practice radiation oncology use radiation technologies, including ionizing radiation, CT scans, MRIs, and ultrasounds to treat cancer.

People who receive radiation therapy for cancer treatment will typically be working with a radiation oncologist. They may also use hyperthermia, or heat treatment, in their work. Some subspecialties of radiation oncology include hospice and palliative medicine, and pain medicine.

Different Subspecialties within Radiology

Subspecialties are specialized areas within the three main branches of radiology. Diagnostic radiologists, interventional radiologists, and radiation oncologists all have different fields in which they may subspecialize. There are also a number of intersectional subspecialties that include radiologists from all three backgrounds.

These are the subspecialties in which a radiologist might have expertise in:

Hospice and Palliative Medicine: Providing End-of-Life Care

Radiologists in all three fields are able to subspecialize in hospice and palliative medicine. These radiologists help to prevent and ease the suffering of patients who have been diagnosed with life-limiting illnesses, such as late-stage cancer. They work to optimize a patient’s quality of life and may also offer support for families.

Neuroradiology: Treating the Neurological System

Neuroradiology is a subspecialty often practiced by diagnostic and interventional radiologists. Neuroradiologists work within the neurological system, which includes the brain, sinuses, spine and spinal cord, neck, and central nervous system.

Neuroradiology can help treat:

  • Aging and degenerative disorders
  • Cerebrovascular diseases
  • Cancer
  • Other traumatic injuries or conditions.

Radiologists in this field commonly use medical imaging techniques such as angiography and MRIs (American Board of Radiology).

Nuclear Radiology: Using Radioactive Substances for Medical Imaging

Nuclear radiologists typically work within the diagnostic and interventional radiology fields. These physicians use small amounts of radioactive substances, including radiotracers, to create images and get information to render a diagnosis. They typically use PET, and SPECT scans to do so (American Board of Radiology).

Nuclear radiology can be very helpful in treating thyroid conditions, including hyperthyroidism and thyroid cancer. It is also often used to treat other kinds of cancer, including lymphoma, and can help with the pain brought on by cancer (CDC).

Pain Medicine: Easing Pain with Radiation Therapy

Diagnostic radiologists, interventional radiologists, and radiation oncologists may all have a subspecialty in pain medicine. These physicians provide pain relief care for all patients, including those with acute, chronic, or even cancer pain, in both in-patient and out-patient environments. They also work closely with other types of doctors to properly coordinate a patient’s ideal pain relief regimen.

Pediatric Radiology: Safely Providing Radiology for Children

Pediatric radiologists in the diagnostic and interventional radiology fields diagnose and monitor congenital disorders, and those present mainly in children and infants. They also work with children who have conditions that can cause more problems later in life.

An important part of a pediatric radiologist’s job is making sure all imaging techniques, including x-rays, CT scans, MRIs, and nuclear medicine, are administered properly and safely enough to treat young children.

Vascular and Interventional Radiology: Treating Vascular Conditions

Diagnostic radiologists have the option to subspecialize in vascular and interventional radiology. These physicians use a variety of medical imaging techniques to diagnose and treat disease, including:

  • CT scans
  • MRIs
  • Digital radiography
  • Fluoroscopies
  • Sonographies

Vascular and interventional radiology is used to treat conditions like cardiovascular disease, cancers, and even varicose veins therapies used by these subspecialists include:

  • Stent placement
  • Drainage
  • Angioplasty
  • Embolization

Benefits Offered by Medical Imaging Technology

Experts agree that medical imaging is one of the most widely beneficial and useful medical developments in recent history. The New England Journal of Medicine has even ranked medical imaging as one of the top medical developments of the past 1,000 years!

Below, you’ll find a list of some of the top benefits offered by medical imaging technology:

Early Detection of Diseases and Other Conditions

Medical imaging by radiologists has made it possible for doctors to detect diseases much earlier on in their progression. This is especially useful for asymptomatic conditions, or those that show no outward symptoms. When doctors are able to catch a harmful disease earlier, there’s more that can be done for the patient treatment-wise.

Most health issues are much easier and less expensive to treat in the earlier stages, while those caught late tend to require expensive, intense treatment or invasive surgeries.

One example of how early detection with medical imaging has saved countless lives is digital mammograms. Digital mammograms are used to detect breast cancer and can catch signs of it an average of two years before a tumor would even begin to form. This gives those affected less invasive and a greater number of options for their next step.

Quicker, More Reliable Diagnoses

Medical imaging procedures can render a faster and more accurate diagnosis, because the radiologist can actually see what’s causing a problem. It’s also far safer than having the patient undergo an unnecessary exploratory surgery and can help doctors better determine when surgery is actually needed.

Most medical imaging requires little to no special preparation. With CT scans, you may be asked not to eat anything less than four hours prior to the scan, and PET and SPECT scans will require you to either take a small dose of radiotracers orally or intravenously.

Barring special circumstances, these are the only preparative measures that need to be taken prior to a medical imaging procedure.

Better Monitoring of Known Conditions

Medical imaging can also help radiologists, and other types of physicians better monitor the progress of known conditions and how well these conditions are responding to ongoing or previous treatment.

Diagnostic imaging is painless and non-invasive, so patients who suffer from conditions that need to be monitored will be subjected to less invasive procedures, including exploratory surgeries. This can, in turn, reduce the length of time a patient spends in the hospital for their condition.

Imaging technologies can show if and how a condition is progressing, how it’s responding or not responding to treatment, and the severity of any internal injuries, like bone fractures.

Medical animation, biovisualization and medical illustration

The terms medical animation, biovisualization and medical illustration are sometimes confused with medical imaging.  Medical animation is the process or product of creating a 3D educational film about a physiological process or other medical topic, which often includes models built from scratch.  Biovisualization is the process of representing biological data visually and may include processing medical imaging data.  Medical illustration is the process or product of creating any  illustration including 2D and 3D visuals of biological and medical topics and may encompass medical animation.

Each of these may be based on or include data and images acquired through medical imaging technologies.

What are Radiologists’ Credentials

Becoming a radiologist will require medical degree, along with the proper licenses and certifications for your state. According to CME Science, you’ll need a Doctor of Medicine (M.D.) or Doctor of Osteopathic Medicine (D.O.) to become a radiologist.

After graduating with from medical school, many prospective radiologists, or radiology technicians as they’re sometimes called, choose to do a radiology residency at a hospital. This may or may not be required, depending on your state, but could be helpful in making connections and building your resume!

After all your training is complete, you’ll need to pass a state exam to become a licensed radiologist. This exam varies by state and may require you to complete a certification program with the American Registry of Radiologic Technologists.

Even if your state does not require this certification for licensing, it may be beneficial to do so anyway to increase job prospects.

Below is a useful introduction to medical imaging from the University of Buffalo:

 

 

Final Thoughts

While the terms medical imaging and radiology tend to be used interchangeably, they are far from the same thing. Radiology refers to the use of radiation technologies to diagnose and treat diseases and injuries, while medical imaging is a subset of these radiation technologies used by radiologists.

Radiologists may specialize in many different areas, but all radiologists use medical imaging to one degree or another.

Click on the following link to learn how to improve the quality of MRI images.

Dr. J

Dr. J has worked in biology all his life and holds several advanced degrees and certificates in biology, anatomy, scientific illustration, 3d animation and motion graphics. He has always had an interest in teaching others the wonders of biology using the latest advances in graphics, including visualization, digital microscopy, animation, illustration, VR and interactive media.

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