Some types of scans include X-rays, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound scans. Medical professionals use scans to help diagnose a range of health conditions.

They can also use them to track the progress of diseases, plan surgical procedures, and monitor pregnancies.

This article outlines what doctors use medical scans for. It also explores several common types of scans in more detail.

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Medical scans help doctors seeTrusted Source detailed images of the internal structures of the body. These images can help them diagnose or monitor a number of medical conditions. They can also use scans to see abnormalities in the body.

Medical professionals can also use scans to assist with surgical procedures. For example, they may carry out a scan to locateTrusted Source the exact site of a tumor so a surgeon can remove it.

X-ray scans use X-rays to create detailed imagesTrusted Source of structures inside the body. X-rays are a type of electromagnetic radiation. They can pass through a person’s body.

During an X-ray scan, X-rays travel through the body. As they do this, different tissues in the body absorb different amounts of the rays.

The rays then pass through the body and into an X-ray detector on the other side of the body. The detector then creates an image that represents the “shadows” formed by the different tissues in the body.

Bones absorb large amounts of X-rays. This means that less of the rays pass through to the X-ray detector on the other side. This means that bones will appear whiter than other tissues in the image.

Tissues that X-rays pass through easily will then display in shades of gray. The more rays that pass through the tissue, the darker they will appear in the X-ray image.

Medical professionals can use X-ray scans to:

CT scans are a type of imaging scan that useTrusted Source X-rays to create three-dimensional images of structures inside the body.

During a CT scan, the radiographer will aim a narrow beam of X-rays at a specific part of the body. They then rotate the beams around the body. A digital X-ray detector then picks up these rays and creates a cross-sectional image of a part of the body. Medical professionals may refer to this image as a “slice”.

The CT machine’s computer may then digitally stack these slices on top of one another to create a three-dimensional image, which makes it easier for medical professionals to identify basic structures and spot abnormalities.

Medical professionals can use CT scans to:

Medical professionals use MRI scans to create detailed, three-dimensional imagesTrusted Source of structures inside the body.

MRI scanners use powerful magnets and radio wavesTrusted Source to create these images. The magnets produce a strong magnetic field that forces protons within the body to align with that field.

A radiologist will then use the MRI machine to pass radio waves through the body. These waves cause the protons in the body to move from their original position. When the radiologist turns the radio waves off, the protons will move back into their original position.

The MRI sensors can then detect the energy that these protons release as they realign with the magnetic field. The MRI computer then turns the energy that the MRI sensors detect into three-dimensional images.

MRI scans differ from CT scans and X-rays as they do not use the potentially damaging ionizing radiation of X-rays. The following structures appear more clearly in an MRI scan than regular X-rays or CT scans:

MRI scans can help medical professionals to:

  • locate tumors
  • observe different brain structures
  • determine which parts of the brain activate during certain tasks
  • diagnose soft tissue injuries
  • monitor the effects of certain treatments
  • assess a person’s neurological status and neurosurgical risks

Ultrasound scans use ultrasound waves to create imagesTrusted Source of structures and tissues inside the body.

During an ultrasound scan, a medical professional will place a probe onto the person’s skin. This probe emits high-frequency ultrasound waves that bounce off certain parts of the body.

The ultrasound probe then picks up these waves as they bounce back. After this, the ultrasound waves hit the transducer and generate electrical signals, which then make their way to the ultrasound scanner. The scanner then turns these signals into a live, moving image of tissues or organs.

Medical professionals also use ultrasound scans to create images of organs and other parts of the body. They can use these to look for abnormalities in the:

Additionally, healthcare professionals use ultrasound scans to monitorTrusted Source the health of a fetus during pregnancy. These scans allow medical professionals to:

  • monitor the growth of the fetus
  • carry out an anatomical survey of the fetus
  • locate the placenta
  • look at the amniotic fluid
  • observe the pelvic organs in the pregnant person

An echocardiogram is similarTrusted Source to an ultrasound scan. It uses ultrasound waves to create images of the heart and the surrounding blood vessels.

During an echocardiogram, a medical professional uses a small probe to send out high-frequency sound waves. These waves create echoes when they bounce off different structures in the body.

The probe then picks up these echoes and turns them into a moving image.

Echocardiograms can showTrusted Source:

  • the size and shape of the heart
  • how well the heart is working
  • problems with the heart valves
  • weakness or dysfunction in the wall or muscle of the heart
  • blood clots in the heart
  • how a person is responding to medications and other treatments

An ECG is a type of test that medical professionals use to measureTrusted Source the electrical activity of the heart.

ECG tests can allow healthcare professionals to measure the time it takes for electrical waves to pass through the heart. ECGs also allow them to measure the amount of electrical activity that passes through the heart muscle.

This test can help medical professionals to understand whether the electrical activity in the heart is:

  • fast
  • slow
  • irregular

It also allows them to determine:

  • if there is damage to parts of the heart
  • if parts of the heart are too large
  • if parts of the heart are working too hard

ECGs can help medical professionals diagnose:

PET scans use radiation to create images of structuresTrusted Source inside the body.

During a PET scan, a medical professional will inject a person with a radiotracer. Alternatively, a person may swallow or inhale the radiotracer. This substance collects in different parts of the body.

The PET scanner can then detect the areas in the body where the radiotracer does and does not build up. The PET scanner then creates images of structures inside the body.

Healthcare professionals most commonly use PET scans to diagnose different types of cancer.

Medical professionals commonly use scans to help diagnose medical conditions.

They can also use scans to track the progress of diseases, monitor pregnancies, measure electrical activity in the body, and plan surgical procedures.

Common types of scans include X-rays, CT scans, MRI scans, ultrasound scans, echocardiograms, ECGs, and PET scans.