imaging exam at Adams Diagnostic Imaging in Gettysburg, PA

The Differences Between a CT Scan and PET Scan

CT scans and PET scans are both procedures used to create images of the body’s tissues, organs, and bones. However, since they have different uses, these two procedures are quite different.


Your physician will prescribe the scan that addresses your needs effectively, but if you’re curious about what they are and how they work, this guide will give you a basic understanding.

What Is A CT Scan?

A computed tomography (CT) scan works with x-ray technology to make detailed images of bones, organs and other inner structures of the body. A CT scan shows the shape and size of the organs and tissues. This kind of imaging scan is fast, painless and doesn’t require the injection or consumption of any chemicals.

A doctor may ask you to undergo a CT scan in order to diagnose the root cause of certain symptoms or to determine the severity of an injury. CT scans will expose your body to a certain amount of radiation. While this radiation is generally less than what you’re exposed to during a conventional x-ray, it isn’t usually recommended for kids or pregnant women, except when it’s unavoidable.

What Is A PET Scan?

A positron emission tomography (PET) scan uses a technology called molecular imaging. Before beginning a PET scan, a small amount of radioactive tracer is injected into a vein in your arm. This radioactive chemical will travel into your bloodstream and be absorbed by the tissues and organs that are being studied.

Using a radioactive tracer will enable the PET machine to detect your organs and tissues and produce three-dimensional images. Molecular imaging offers a precise way of diagnosing diseases at the molecular and cellular level. That’s why it’s used to detect brain disorders, heart diseases, cancers and any ailments linked with the central nervous system.

What Is the Difference?

The procedures contain some key differences:

  • Completion time: A CT scan is quick, and it can be completed within 5 minutes. PET scans, on the other hand, could take up to 35 minutes for the test, in addition to the setup time.
  • Type of image produced: CT scans produce two dimensional (2D) images while PET scans produce more detailed three-dimensional (3D) images.
  • Technology used: CT scans work with x-rays, which are non-invasive, while PET scans use radioactive tracers called positrons that must be injected.
  • Diagnostic applications: CT scans provide a clear image of bones and tissues, and they can easily reveal abnormalities present in soft tissues. PET scans show metabolic changes in tissues or organs earlier because they show changes at the cellular level. But a CT scan can only show the same change after the disease has started to cause changes in the normal structure of the organs or tissues.

Contact Adams Diagnostic Imaging Today

If you’ve been diagnosed with any type of cancer or you’re caring for a loved one who has, you can trust Adams Diagnostic Imaging for compassionate, professional care. Contact us now for more information on how to get the best imaging services delivered by compassionate staff who work with the most efficient imaging machines.

Learn More About Diagnostic Imaging Scans

sunset over water

Risks From Radiation Treatment

Risks From Radiation Treatment

When it comes to radiation imaging and radiation treatment, there has been rising concern over possible risks, leading some patients to neglect to participate in scans and treatments that could lead to the overall improvement of their health.

woman standing on beach

If you’re worried about the risks of radiotherapy and radiology scans, this information will help.

What Is Radiation Treatment?

While radiation therapy is a treatment used to decrease or eliminate the detrimental effects of medical conditions like cancer, blood disorders, thyroid disease or noncancerous growths, radiological scans like X-rays and CT scans are used to search for and diagnose cancer, tumors, blockages, broken bones and other conditions.

Both methods use radiation for their respective purposes — either to target and eliminate dangerous cells or to take images with the help of electromagnetic radiation waves. Because of their employment of modest amounts of radiation — which, in very large doses, can be dangerous to the human body — both radiation therapy and radiological scans are often a source of concern when it comes to potential health risks.

What Are the Risks of Radiotherapy?

When the body absorbs radiation, the exposure can cause damage to molecular structures and potentially lead to physical harm, which is why some are concerned with receiving radiation treatment or undergoing radiological scans. However, the damage that can occur as a result of radiation — including skin burns, hair loss and theoretically increased cancer risk — only happens in the case of exposure to very high doses of radiation.

When it comes to the low doses of radiation used in radiological imaging and radiation treatment, there’s little to no increased risk of cancer. In fact, a patient’s chance of developing cancer following a radiation treatment is only 1 in 2,000 — meaning there is a 99.9995 percent chance of not developing any adverse conditions from medical radiation. In comparison, the average American has a much higher percentage chance of dying of appendicitis — 1 in 263 — or developing lung cancer — 1 in 714 — than suffering from any radiation therapy side effects.

It’s also important to understand the difference between external and internal radiation exposure. While many patients are concerned with the possibility of retaining radiation within their bodies after a radiological scan or radiotherapy session, these procedures are forms of external exposure, which only submit the body to penetrating radiation that passes straight through.

Internal exposure, on the other hand, occurs when a person comes into contact with radioactive material — through direct inhalation, ingestion or physical contact — and is much more dangerous. While internal exposure is likely to have hazardous risks, it never occurs in medical procedures, and the external exposure of radiation treatment poses very little risk.

Come to ADI for Reliable Radiology

Now that you’re confident about the relative safety of radiation therapy and radiology, you’ll want to be just as comfortable with the professionals performing your procedure. Offering compassionate care and a background of comprehensive experience, Adams Diagnostic Imaging (ADI) provides the top radiologists to expertly administer radiological imaging services. Contact us today to get more information or arrange an appointment.

Learn More About Treatments And Diagnostic Imaging