5 Ways a CT Scan Is Different From a PET Scan

Every year, millions of Americans undergo imaging tests to assist doctors in the diagnosis and prognosis of health conditions including cancer. These imaging techniques provide doctors with valuable information enabling them to make quick diagnosis and recommend appropriate treatment options. But how do these tests work, why are they used, and what are the differences between CT scans and PET scans? Read on to know more.  

What is a CT scan?   

A CT scan or computerized tomography scan is a type of medical imaging test that uses X-rays to create detailed, cross-sectional images of different organs of the body. It can also be used to guide biopsies or other procedures to obtain a tissue sample for analysis.

During the procedure, the patient lies on a table that slides into a doughnut-shaped machine called a CT scanner. The computer then uses this data to construct a series of detailed, 3D images of the organs inside the body.  

Advantages of CT scan   

• High resolution: CT scans provide detailed, high-resolution images to detect any small tumors or abnormalities.   

• Fast and non-invasive: This is a quick and painless procedure, typically taking only a few minutes to complete if compared to other procedures.   

• Versatile: It can be used to image many different parts of the body, including the chest, abdomen, pelvis, and bones.

• Widely available: This is a common imaging option widely available in most hospitals and imaging centers, making it a convenient option for patients.   

  Disadvantages of CT scan   

• Radiation exposure: It is done using X-rays, which expose the patient to a small amount of radiation. Although the risk of harm from this radiation is very low, it can increase over time, especially for patients requiring multiple scans.

• Contrast material risks: In some cases, CT scans may require the use of contrast materials, which are then injected into the patient's body in order to get better image quality. These materials sometimes can cause reactions or problems in some patients.   

• False positives: Sometimes, CT scans may detect abnormalities that may not be cancerous. These false results can lead to additional unnecessary testing for the patient. 

What is a PET Scan?    

A PET scan or positron emission tomography is a common medical imaging test that uses a radioactive tracer. This test reveals the metabolic or biochemical functions of tissues and organs in a clearer and more precise way.  

During a PET scan, the patient is injected with a small amount of a radioactive substance, which is not harmful and absorbed by the body's cells easily. As the substance decays, it emits positrons, which can be detected by a special camera, commonly known as a PET scanner. The computer then uses this data to construct a series of detailed, 3D images of the organs inside the body to help detect any abnormalities.    

Advantages of a PET Scan    

• High sensitivity: It is highly sensitive and can detect even small tumors or abnormalities that may be missed by other types of imaging tests.

• Functional imaging: It can show how well the body's tissues and organs are functioning, providing critical information for cancer diagnosis and treatment.   

• Non-invasive: PET scans are also a quick and painless procedure that typically takes only a few minutes to complete.   

• Can help guide treatment: It can be used to guide treatment decisions, such as determining the effectiveness of chemotherapy or radiation therapy for cancer.  

Disadvantages of PET Scan  

• Radiation exposure: This procedure uses radioactive tracers, which expose the patient to small amounts of radiation which are not considered harmful. Although the risk of harm from this radiation is very low, it can add up over time, especially for patients who require multiple PET scans over a shorter period of time.

• Availability: PET scans are not widely available if compared to the other types of imaging tests and may not be available in all hospitals or imaging centers.   

Differences Between a CT Scan and a PET Scan  

Both CT scans and PET scans are non-invasive and relatively painless procedures used in diagnosis of cancer and other diseases. Also, both imaging tests use radiation and can be combined or "fused" together to provide more detailed information about the body's tissues and organs. However, these two scans have several key differences, which are as follows:  

1. Types of radiation used

CT scans use X-rays to create images, while PET scans use a radioactive tracer.  

2. Effects of radiation

In the case of a CT scan, radiation doesn’t stay in the body after the procedure. During the PET scan, since the patient is injected with a small amount of radioactive substance, a small amount of radiation can stay in the body after the procedure. In this case, most of the radiotracer leaves the body within a day or two through bodily fluids. The rest of it decays naturally over time, and there is no need to take any special precautions or treatment. 

3. Information provided

CT scans provide detailed images of the body's tissues and organs, while PET scans provide information about how well the body's tissues and organs are functioning.  

4. Use in cancer diagnosis

CT scans are typically used to detect and stage cancer, while PET scans are used to determine whether cancer has spread to other parts of the body.  

5. Availability

CT scans are widely available in most hospitals and imaging centers, while PET scans may not be as widely available.  

6. Cost

CT scans are generally less expensive than PET scans.  

Schedule Your Appointment Today  

In some cases, providers recommend a combination of PET and CT scans to increase the accuracy of a cancer diagnosis. Also known as PET-CT imaging, this technique combines the benefits of both tests. This combined imaging test provides detailed information about both the structure and function of the body's tissues and organs, and it is also used to check the efficiency of the treatment procedure. However, the type of imaging test used for cancer diagnosis and monitoring depends on individual needs and the specifics of their cancer diagnosis.   

To learn more about cancer treatment options, contact ACTC, one of the best cancer treatment centers in Florida, and schedule an appointment.