Last Updated on November 27, 2025 by Bilal Hasdemir

Every year, 1.5 million PET scans are done in the United States. They are key in finding and treating diseases like cancer and brain disorders. If you are curious about how long does a PET scan take, the entire process usually lasts about two to three hours. This includes the time for a radioactive tracer to circulate through your body, which takes about 30 to 60 minutes, and the actual scanning part, which typically takes 20 to 30 minutes. After the scan, you can usually resume your daily activities, with some advice to drink plenty of fluids to help flush the tracer from your system.​

Positron Emission Tomography (PET) is a high-tech way to see how the body works. Knowing how long a PET scan takes is important. It helps doctors plan the best treatment.

A PET scan procedure has three main steps: getting ready, scanning, and making images. Even though scanning time can change, knowing the whole process can make you feel better.

Key Takeaways

• PET scans are a vital tool for diagnosing many diseases.
• The time it takes for a PET scan can differ based on the procedure.
• Learning about the PET scan process can lessen anxiety.
• PET scans offer deep insights into the body’s metabolic activities.
• The PET scan process includes preparation, scanning, and image creation.

What Is a PET Scan: Understanding the Basics

A PET scan is a tool that uses a radioactive tracer to see how the body works. It’s key for finding and tracking diseases like cancer, brain issues, and heart problems.

Definition and Purpose of Positron Emission Tomography

Positron Emission Tomography, or PET, is a test that shows how the body’s parts work. It’s different from other tests because it looks at how active tissues are, not just their shape. This is done with a tiny amount of radioactive tracer that shows up on the PET scanner.

The main goal of a PET scan is to spot and track diseases by looking at how active the body’s tissues are. It’s super helpful in finding cancer because cancer cells use more energy than normal cells.

How PET Scans Differ from Other Imaging Tests

PET scans are different from CT and MRI scans. While CT and MRI show what the body looks like, PET scans show how it works. This makes PET scans great for finding cancer, checking if treatments are working, and spotting brain problems.

Imaging Test	Primary Use	Information Provided
PET Scan	Metabolic activity assessment	Functional information about tissues and organs
CT Scan	Anatomical imaging	Detailed cross-sectional images of the body’s structures
MRI	Soft tissue imaging	High-resolution images of soft tissues, organs, and other internal structures

Doctors say PET scans have changed how we fight cancer. They help figure out how serious the cancer is and what treatment to use.

“The integration of PET imaging into clinical practice has significantly improved patient outcomes by facilitating more accurate diagnoses and tailored treatment strategies.”

In short, PET scans are a powerful tool that gives us a deep look into how the body works. Knowing how PET scans work helps us see their value in keeping us healthy.

How Long Does a PET Scan Take: The Complete Timeline

Many patients wonder how long they’ll be in the PET scanner. The time varies based on several factors. Usually, the scan itself lasts about 30 minutes to an hour.

Average Time Inside the Scanner

The scanning time is usually between 30 to 60 minutes. You’ll lie on a table that slides into the scanner. It’s important to stay very quiet and follow the technologist’s instructions.

For a standard PET scan, you’ll spend about 45 minutes inside. But, this can change based on your specific scan.

Total Appointment Duration Expectations

The scan itself might take 30 to 60 minutes. But, the whole visit will take longer. Plan to spend at least 2 hours at the facility.

Procedure	Average Time
Registration and Preparation	30 minutes
PET Scan	30-60 minutes
Additional Procedures (if necessary)	15-30 minutes
Total Appointment Time	1.5-3 hours

Medical experts say, “The total time for a PET scan can vary. But, patients should expect to spend a couple of hours at the facility.” This includes getting ready, the scan, and any extra steps needed.

Factors Influencing Total Time

• Type of PET scan (full-body vs. targeted)
• Need for additional imaging or procedures
• Patient-specific factors, such as mobility or the need for sedation

Knowing these factors helps you prepare for your PET scan. It also helps you understand how long it might take.

The PET Scan Procedure: Step-by-Step Process

The PET scan process has several steps, from getting ready to the actual scan. Knowing these steps can make patients feel more at ease and ready for their visit.

Pre-Scan Preparation at the Facility

When you arrive at the facility, you’ll go through pre-scan prep. This includes:

• Changing into a hospital gown to ensure that there are no external factors interfering with the scan.
• Removing any jewelry or other metal objects that could affect the scan.
• Following specific dietary instructions provided before the scan day, which may include fasting or avoiding certain foods and drinks.

It’s important to follow these instructions carefully to get accurate and useful images.

What Happens During the Actual Scan

During the PET scan, you’ll lie on a table that slides into the PET scanner. The scanner picks up signals from the radioactive tracer in your body. Here’s what happens during the scan:

1. The table moves slowly through the scanner, capturing images of your body’s metabolic activity.
2. The scan is done in sections, with the table moving to different positions to get all the views needed.
3. You’ll need to stay very quiet and might be asked to hold your breath for short times to get clear images.

The whole process is made as comfortable as possible. The actual scanning usually takes about 30 minutes to an hour. This depends on the type of scan and the area being scanned.

By knowing the PET scan procedure and what to expect, patients can better prepare for this important diagnostic tool.

Factors That Affect PET Scan Duration

Knowing what affects PET scan time is key for setting patient expectations and planning schedules. The time spent in a PET scanner varies due to several important factors.

Full Body vs. Targeted Scans

The type of scan greatly influences the time needed. Full body PET scans for diseases like cancer take longer. They can last from 30 to 60 minutes. On the other hand, targeted scans for specific areas like the brain or heart are quicker, lasting 15 to 30 minutes.

The size of the scan area affects the time needed. It shows how much of the body needs to be imaged. Facilities might adjust the scan based on the doctor’s needs.

Patient-Specific Factors That May Extend Scan Time

Individual factors can also change how long a PET scan takes. For example, patients with a higher BMI might need more time for quality images. Also, those who find it hard to stay calm or follow breathing instructions might need extra time.

Other factors include medical conditions and how well the patient can follow instructions. Facilities consider these when planning and doing PET scans. This ensures the best results for patients.

Understanding these factors helps patients prepare for their PET scan. It also helps them know what to expect during the process.

PET-CT Combination Scans: Additional Time Considerations

Combining PET and CT scans is a common practice. It enhances diagnostic accuracy by providing both functional and structural information. This is very valuable in oncology, where it helps assess tumor activity and location.

Why PET and CT Scans Are Often Combined

PET scans show how tissues work, while CT scans give detailed images. Together, they offer a full view of a patient’s condition. This combination helps find problems better and understand how widespread they are.

“The mix of PET and CT scans is a big step forward in medical imaging,” experts say. It boosts confidence in diagnosis and helps plan treatments.

How Much Longer Combined Scans Take

PET-CT scans take longer than PET or CT scans alone. They usually add 15 to 30 minutes to the scan time. This extra time is for getting ready, taking the CT data, and merging the images.

• The total scan time is usually between 30 to 60 minutes.
• Preparation and image taking add to the time.
• The detailed view they offer makes the extra time worth it.

In summary, while PET-CT scans take longer, they provide more detailed information. This makes them a key tool in medical diagnosis and treatment planning.

Preparing for Your PET Scan Appointment

A PET scan appointment needs some preparation for accurate results and comfort. Proper preparation can lower anxiety and make the scan go smoothly.

Dietary and Medication Guidelines Before the Scan

Before a PET scan, follow specific dietary instructions for accurate results. Patients usually fast for a few hours before the scan. The exact time depends on the scan type and facility rules.

Also, some medications might need to be avoided or adjusted before the scan. Tell your healthcare provider about all your medications, including supplements and over-the-counter drugs.

Dietary Instruction	Guideline
Fasting	Typically required for 4-6 hours before the scan
Caffeine and Sugar	Avoid for at least 4 hours before the scan
Medication Disclosure	Inform your healthcare provider about all medications and supplements

What to Wear and Bring to Your Appointment

Wear comfortable clothes that allow easy movement on the day of your PET scan. Avoid jewelry or clothes with metal parts to prevent interference. You might need to change into a hospital gown.

Bring any important medical records, insurance info, and a list of your medications. Being prepared helps the process run smoothly.

The Science Behind PET Scans: How They Work

PET scan technology uses radioactive tracers to show how active the body’s tissues and organs are. This method gives doctors important insights into the body’s functions. It helps in diagnosing and treating many health issues.

Radioactive Tracers and Their Function

Radioactive tracers are substances that give off positrons, the opposite of electrons. When positrons meet electrons, they destroy each other, creating gamma rays. These rays are what the PET scanner picks up.

The most common tracer is Fluorodeoxyglucose (FDG). It’s like glucose but is used to find areas with high activity, like tumors or brain areas.

How PET Scanners Detect Metabolic Activity

PET scanners find the gamma rays from the tracers to create detailed images. The scanner’s detectors, in a ring around the body, catch these rays. This helps pinpoint where the tracer is in the body.

The images show how active different parts of the body are. This is very useful for doctors to diagnose and track diseases like cancer, brain disorders, and heart disease. PET scans are very sensitive to changes in the body, making them a key tool in medicine and research.

Patient Experience During the PET Scan

Patients often worry about what happens during a PET scan. They might feel anxious about their comfort. Knowing what to expect can help ease these worries.

Physical Sensations and Comfort Levels

During a PET scan, patients lie on a table that moves into a scanner. The scanner looks like a big, doughnut-shaped machine. Most find it okay, but some might feel uncomfortable because they have to stay very quiet for a long time.

Common physical sensations include feeling cold. This is because the room is cool and the contrast agent or tracer might make you feel chilly. Some might also feel a bit of pain if they’re in an uncomfortable position for too long.

Tips for Managing Anxiety and Claustrophobia

For those with anxiety or claustrophobia, there are ways to make the PET scan easier. Communication with the medical team is very important. Let them know about your anxiety or claustrophobia before the scan. This way, they can help you more.

• Try relaxation techniques like deep breathing or meditation before and during the scan.
• Having a friend or family member there can offer emotional support.
• In some cases, mild sedation might be given to help you relax during the procedure.

 radiologist, says, “Talking openly about anxiety is key. We can usually provide extra support or make changes to make you more comfortable.”

“The more informed patients are, the less anxious they tend to be. We encourage patients to ask questions and share their concerns.” -Radiologist

Tips	Benefits
Relaxation Techniques	Reduces anxiety and stress
Emotional Support	Provides comfort and reassurance
Mild Sedation	Helps in managing severe claustrophobia

By understanding the PET scan process and using the support available, patients can handle their anxiety and discomfort better. This makes the whole diagnostic process easier.

After the Scan: Recovery and Monitoring Period

After a PET scan, patients go through a recovery and monitoring phase. This is key to check if the scan worked well and to keep the patient safe.

Immediate Post-Scan Procedures

Right after the PET scan, patients are watched closely. Medical staff look for any quick reactions to the tracer. They tell patients to drink lots of water to get rid of the tracer. This helps avoid any side effects.

Most patients can go home soon after the scan, unless there’s a problem. It’s a good idea to have someone with you when you get home. This is because the scan might make you feel sleepy.

When You Can Resume Normal Activities

Usually, patients can go back to their usual activities right after the scan, unless told not to. The tracer used in the scan doesn’t stay in the body for long. Most people don’t feel any lasting effects.

But, it’s important to listen to what your doctor says. If you had sedation, you might need to wait a bit longer to do things that need you to be fully awake, like driving.

To recover well, patients should drink plenty of water and follow their doctor’s advice. If you feel very sick or have trouble breathing after the scan, get help right away.

PET Scan Results: Processing and Wait Times

PET scan results processing involves several steps before the final report is ready. After the scan, the images are reviewed by healthcare professionals. This includes radiologists and nuclear medicine specialists.

Processing Time for PET Scan Results

The time to get PET scan results varies. It depends on the facility’s workload and the scan’s complexity. Usually, patients wait a few days for their results.

“The processing time for PET scan results typically ranges from 24 to 72 hours, though it can be longer in some cases,” say medical professionals. This time is needed for a detailed analysis of the scan data.

Understanding Your PET Scan Images and Reports

When the results are ready, patients get a detailed report. This report includes images and descriptions of the scanned areas. It highlights any abnormalities or concerns.

It’s important for patients to discuss their PET scan images and reports with their healthcare provider. This helps understand the results fully. It also clarifies any questions or concerns about diagnosis or treatment.

Getting and understanding PET scan results is key in the diagnostic process. Knowing what to expect and how to interpret results helps patients navigate their healthcare journey.

Common Uses of PET Scans in Medical Diagnosis

PET scans are key in medical diagnosis, giving insights into many health issues. They show how the body’s cells work, helping doctors manage and find diseases.

Cancer Detection, Staging, and Treatment Monitoring

PET scans are a big help in fighting cancer. They spot tumors by seeing how active they are. This helps doctors know how serious the cancer is and what treatment to use.

Key applications in cancer management include:

• Diagnosing cancer by highlighting areas of high metabolic activity
• Staging cancer by determining the extent of disease spread
• Monitoring treatment response by tracking changes in tumor metabolism
• Detecting cancer recurrence early

Cancer Type	PET Scan Application	Benefits
Lymphoma	Staging and treatment monitoring	Accurate assessment of disease spread and treatment response
Lung Cancer	Diagnosis and staging	Precise identification of tumor location and extent
Breast Cancer	Treatment monitoring and recurrence detection	Early detection of treatment response and possible recurrence

Neurological, Cardiac, and Other Applications

PET scans also help in neurology and cardiology. They help find and manage diseases like Alzheimer’s and Parkinson’s by looking at brain activity.

Cardiac PET scans check how well the heart works. They help find heart disease and see if heart muscle is working right. This info is key for planning treatments and predicting how well patients will do.

Other uses include:

• Checking for infections and inflammation
• Looking at certain brain disorders
• Helping with biopsies and surgeries

Potential Side Effects and Safety Considerations

It’s important to know about the safety of PET scans for those getting them. PET scans help doctors diagnose and track many health issues. But, they use radiation and radioactive tracers, which means we need to think about possible side effects and safety.

Radiation Exposure and Risk Assessment

PET scans use small amounts of radioactive tracers. These tracers emit positrons that the scanner detects. The radiation dose from a PET scan is usually between 1-10 millisieverts (mSv). For comparison, a chest X-ray has about 0.1 mSv.

The debate about PET scan radiation risks is ongoing. High doses of radiation can raise cancer risk. But, the doses in PET scans are lower, making it harder to measure risks. Yet, the benefits of PET scans for diagnosis are often seen as greater than the risks, when used wisely and with careful patient selection.

Procedure	Typical Radiation Dose (mSv)	Comparative Risk
PET Scan (whole body)	5-10	Equivalent to 2-4 years of natural background radiation
Chest X-ray	0.1	Equivalent to a few days of natural background radiation

Possible Reactions to Tracers and Contrast Materials

Another thing to consider with PET scans is reactions to the tracers or contrast materials. Most PET tracers are safe, but some people might have side effects. These can include allergic reactions or changes in heart rate and blood pressure.

Common reactions to PET tracers and contrast materials include:

• Mild allergic reactions (rash, itching)
• Nausea or vomiting
• Headache
• Dizziness

It’s key for patients to tell their doctors about any allergies or sensitivities before a PET scan. Also, patients should be watched during and after the scan for any bad reactions.

Special PET Scan Protocols for Different Patient Groups

Different patient groups need special PET scan protocols. This is true for kids, older adults, and those with mobility issues. They have unique needs for a safe and effective scan.

Pediatric PET Scans: Duration and Special Considerations

Pediatric PET scans need careful planning. Kids’ bodies are smaller and their metabolism is different. Specialized pediatric protocols are used to reduce radiation while getting good images.

• Reduced tracer doses are used based on the child’s weight.
• Scans are often shorter to accommodate children’s shorter attention spans.
• Sedation may be used in some cases to ensure the child remains still during the scan.

Adaptations for Elderly or Mobility-Impaired Patients

Elderly or mobility-impaired patients may need extra help during PET scans. This includes:

1. More time to get onto the scanning table.
2. Extra pillows or supports to help them maintain the required position.
3. Regular breaks if needed during the scan.
4. Assistance from caregivers or family members during the procedure.

It’s important for these patients to be comfortable and still during the scan. Communication with the patient before and during the scan is key to understanding their needs and making necessary adjustments.

By tailoring PET scan protocols to the specific needs of different patient groups, healthcare providers can ensure that all patients receive the best possible care. Whether it’s a child, an elderly individual, or someone with mobility issues, these specialized protocols help in obtaining accurate diagnostic results while prioritizing patient comfort and safety.

Insurance Coverage and Costs Related to PET Scan Duration

Understanding the financial side of PET scans is key. Knowing about insurance and costs is important. The scan’s length can affect the price, so it’s good to know how these things work together.

Factors Influencing PET Scan Costs

The price of a PET scan can change a lot. This depends on the scan’s length, where it’s done, and your insurance. Scan duration is a big factor because longer scans need more resources and special tracers.

Factor	Impact on Cost
Scan Duration	Longer scans increase costs due to additional resource utilization.
Facility	Costs vary between hospitals, diagnostic centers, and private clinics.
Insurance Coverage	Affects out-of-pocket expenses; coverage varies by provider and policy.

Insurance Approval Process and Wait Times

The steps to get insurance approval for PET scans are clear. Understanding the timeline helps patients plan better.

• Pre-approval: Typically takes a few days to a week.
• Claim submission: Requires documentation from healthcare providers.
• Processing: Can take several weeks, depending on the insurer.

Having insurance for PET scans can lower what you pay out of pocket. But, it’s important to know your policy well. This includes your deductible, copays, and any limits on what’s covered.

Conclusion: Planning for Your PET Scan Experience

Knowing what a PET scan is and what to expect is key for a smooth experience. Being informed helps you prepare better and feel less anxious.

Planning well for your PET scan means understanding its length, what you need to do before, and what happens during and after. Knowing it can take from 30 minutes to hours helps you plan your day.

To make your PET scan better, follow your doctor’s advice on food and medicine. Arriving ready at the facility makes your experience more comfortable and efficient.

Preparing for your PET scan and knowing the process helps reduce discomfort. It also makes sure you get the most from the scan’s diagnostic info. A well-planned PET scan is essential for a good diagnosis and treatment plan.

FAQ

Reference

1. Kapoor, M. (2022). Positron emission tomography scan. In StatPearls. NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK559089/